Acute rejection (AR) is a major cause of graft loss. It is primarily a cellular type directed against mismatched donor antigens expressed on the allograft, and generally occurs in the early post-transplant period, especially in the first 3 months. In order to prevent adverse graft outcomes, reliable and timely detection of AR is needed. Diagnosis of AR depends on clinical parameters and biopsy findings. Most cases are asymptomatic and the only finding is an increase in serum creatinine is an indicator of graft function decline. Banff classification is used to diagnose AR and its severity. Anti-rejection treatment response is difficult to predict based on clinical and histopathological findings, and biomarkers could add additional parameters for assessing the risk of adverse graft outcomes.
Impact of acute rejection on graft outcome
With the introduction of immunosuppressive medications, the AR incidence drops, although it remains a major factor contributing to adverse graft outcomes. AR episode also correlates with a significant reduction in long-term allograft survival, with the development of chronic allograft failure (CAN, or IFTA). Various parameters of AR determine the level of risk for adverse graft outcomes including timing, recurrence, severity, and therapy sensitivity of AR episodes.
Late AR that occurs after 3 months carry a poorer prognosis than early, recurrent episode worse than one or no AR. Banff grade II; AR with vascular rejection has a higher risk of graft loss as compared with Banff grade I. as well, AR that does not respond to therapy has a bad prognosis
Treatment of acute renal allograft rejection
Many therapeutic options are available for the treatment of AR. AR can still occur despite optimization of HLA compatibility and the use of induction therapy and maintenance immunosuppression.
These drugs include:
1- Synthetic corticosteroids
Intravenous pulse therapy with high dose-methylprednisolone nowadays has become the first-line therapy for AR in most transplant centres.
2- Polyclonal and monoclonal antibodies
ATG is an effective treatment of AR with high graft survival rates, although; ATG has many complications, such as leukopenia, cytokine release syndrome and viral infections. Due to its complications, ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR.
OKT3 is a monoclonal antibody-based treatment directed to the CD3 molecules, which is associated with T cell receptors (TCR). So, it can modulate TCR resulting in depletion of T cells. OKT3 has been withdrawn from the market due to its lower efficacy and higher side effects compared to ATG.
Most AR episodes can be adequately treated with high-dose corticosteroids. However, about 25 to 30% of these episodes cannot respond to steroids. In these cases, treatment with ATG can result in a salvage rate of 70 to 90%.
Diagnosis of steroid resistance primarily relies on post-transplantation follow-up of clinical parameters reflecting renal allograft function. An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy. If steroid response occurs five days after initiation of the pulse therapy is called a steroid-responsive case.
This 5-day period is also the average time delay used by clinicians before considering a rejection as
being steroid-resistant. Incomplete restoration of graft function in steroid-resistant rejection may lead to progression of chronic damage to the graft and has a detrimental effect on graft outcome.
Assessment of risk for steroid resistance:
Steroid resistance risk prediction at the time of biopsy could prevent unnecessary exposure to high-dose corticosteroid therapy as well, irreversible nephron loss could be avoided.
Clinical and pathologic indicators of steroid-resistant rejection
Clinical parameters and histopathological assessment of kidney biopsies remain the golden standard for evaluating short- and long-term graft outcomes.
Several parameters have been associated with unresponsive to steroid treatment:
1- Acute vascular rejection.
2- Presence of mononuclear cells at endothelial cells of large and small vessels in the graft.
3- Presence of an immune response directed against the microvasculature.
4- Moderate to severe microvascular destruction respond less adequately to steroid therapy.
5- Extensive leukocyte infiltration into the peritubular capillaries (PTC).
6- Circulating leukocytes target HLA molecules expressed on PTC, which results in to cellular rejection.
7- Presence of DSA against HLA molecules, leading to local complement activation and humoral rejection.
8- C4d deposition in PTC has been associated with steroid resistance.
Prognostic biomarkers for steroid-resistant rejection
Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness could provide complementary parameters for assessing the risk of adverse graft outcomes.
a- Immune biomarkers:
Resistance to steroids has been associated with increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B-lymphocyte-, and macrophage signatures.
b- B lymphocytes
The extent of B cell infiltration within the renal allograft was shown to discriminate between steroid-resistant and steroid response AR episodes. Steroid-refractory AR expressed increased intragraft levels of B cell marker CD20 and B-lymphocyte-associated immunoglobulins.
c- Macrophages:
Immunostainings for CD68 revealed the presence of intraglomerular and interstitial macrophages during AR as prognostic markers for steroid resistance and graft outcome. Also, macrophages have been associated with intimal arteritis and C4d in the PTC which are in themselves associated with resistance to anti-rejection therapy.
Challenges for biomarker identification in a clinical context
The definition of steroid resistance varies widely between studies, also, the patient’s character, the timing of AR from transplantation, and differences in immunosuppression therapy, all make interpretation of these biomarkers challenge.
Non-immunological biomarkers
A relatively novel finding is the link between zinc regulation and resistance to anti-rejection treatment with steroids. Relatively high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with steroid resistance.
Combination of immune- and non-immune biomarkers
The underlying mechanisms for steroid-resistant acute rejection are multiple therefore, no single biomarker has been able to predict the response to steroid treatment with both high sensitivity and high specificity.
Glucocorticoid receptor expression
The observed differences in GR expression between responders and non-responders might be a reflection of varying levels of GR autoregulation.
Clinical implication:
Steroid resistance is a complex and multifactorial condition, that includes both immunological and non-immunological factors. Both T cells and macrophages play an important role in the response to steroid therapy. Zinc regulation may play a role in the response to steroid therapy during AR. Kidney transplant recipients who express high intragraft levels of MT and TIMP1 during AR might benefit from extra zinc intake for optimal GC signalling.
Non-invasive methods for monitoring graft outcome
Graft biopsy is the gold standard for the diagnosis of graft outcomes. But it is mainly performed on clinical indications s an invasive procedure. Identification of molecular markers in blood and urine may provide means to monitor graft function more frequently, which could lead to earlier detection of graft dysfunction and timely intervention of the immune process.
Conclusion:
Steroid-resistant AR is a complex and multifactorial condition. Graft infiltration with T-lymphocytes and macrophages correlates with steroid resistance AR which means that AR is related to specific cells population. Zinc regulation and drug metabolism may play a role in the response to steroid therapy during acute renal allograft rejection. Kidney recipients may benefit from adding zinc to optimise GC signalling.
How to change this, my practice?
I will increase the suspicion of steroid resistance AR if the graft function indicators do not subtle by the 5 days of steroid use.
Dalia Eltahir
2 years ago
· Acute rejection (AR) is a dominant risk factor for adverse graft outcome . Approximately 50% of grafts from deceased donors and 30%
of grafts from living donors fail within ten years after kidney transplantation.
Various parameters of AR determine the level of risk for adverse
graft outcome including the timing, recurrence, severity, and therapy
sensitivity of the AR episode . · Treatment of acute renal allograft rejection :good investigation and u sing of immunosuppression drugs lead to decrease incidence of acute rejection . · 1-Synthetic corticosteroidsintravenous pulse therapy with
high-dose methylprednisolone has become the first-line therapy for
AR in most medical centers .
· Polyclonal and monoclonal antibodies ATG therapy causes depletion of circulating T cells and other leukocytes through various mechanisms, including antibody- and complement dependent lysis and the induction of apoptosis but it associated with increase risk of infection..ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR .
· The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes. · Steroid resistance :About 25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone . Renal allograft recipients with steroid-refractory rejection are generally treated with ATG, which results in a salvage rate of 70 to 90% .An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy . · Clinical and pathologic indicators of steroid resistant rejection :1-Acute vascular rejection 2-presence of mononuclear cells at endothelial cells of large and small vessels in the graft 3-extensive leukocyte infiltration into the
peritubular capillaries (PTC .4- C4d deposition
· .Prognostic biomarkers for steroid resistant rejection : · 1-. Immune biomarkers
· 2-Non-immunological biomarkers.
· 3-Combination of immune- and non-immune biomarkers
· 4-Glucocorticoid receptor expression · Methods for monitoring of graft outcome :1-renal biopsies
· 2-Blood test 3-urine analysis . · This information will improve our practice with best flow up and management to the patient .
Wee Leng Gan
2 years ago
Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection.
About 25 to 30% of the renal allograft rejection not responded to steroid treatment alone. Majority acute graft rejection can be treated with high dose steroid. Renal transplant recipients with steroid-refractory rejection may be treated with ATG, which results in a salvage rate of 70 to 90%. Factors associated resistance to therapy in graft rejection include presence of mononuclear cells at endothelial cells of large and small vessels in the graft, presence of an immune response directed against the microvasculature, moderate to severe microvascular destruction, extensive leukocyte infiltration into the peritubular capillaries and C4d deposition in PTC has been associated with steroid resistance. The prognostic markers associated with steroid resistant include increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophages. On the other hand, increase metallothioneins and tissue inhibitor of metalloproteinase-1 at graft biopsy is associated with steroid resistance. Increased expression of metallothioneins may lead to inhibition of the anti-inflammatory effects of zinc-dependent recruitment of HDAC-2 by the GC-GR complex. microRNAs are emerging as potential biomarkers for the outcome of acute renal allograft rejection. In conclusion, refractory to steroid treatment in acute graft rejection involve complex mechanism and due multifactorial conditions. Zinc regulation and drug metabolism may affect the response to steroid treatment in graft rejection. Thus, , kidney transplant recipients with graft rejection may benefit from additional zinc intake to optimize GC signaling.
Mohamed Fouad
2 years ago
Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection
Acute rejection (AR) is a dominant risk factor for adverse graft outcome. AR is primarily a cellular immune response directed against mismatched donor HLA antigens present on the allograft cells.AR usually occurs during the early post-transplant period, with the highest risk in the first 3 months. Detection of AR in time is important for the prevention of adverse graft outcome. Diagnosis of AR episodes through laboratory and histopathological diagnosis of graft biopsy samples. Most patients who develop AR episode are asymptomatic and present only with an increase in serum creatinine levels as an indicator of a decline in renal graft function.
Impact of acute rejection on graft outcome
The incidence of AR episodes is reduced with the introduction of new immunosuppression era from over 80% in the 1960s to below 15% nowadays. As well as, the short term graft survival has been improved, with one-year graft survival rates in excess of 90%.
Despite these advances in short term graft outcome, the long-term
graft outcome improved only marginally over the past two decades. AR continues to be a primary cause of renal allograft failure. Approximately 10% of all graft losses are directly caused by acute renal allograft rejection. patients with acute vascular rejection (Banff classification grade II) have a higher risk of graft failure compared to patients with acute tubulointerstitial rejection (Banff classification grade I). AR is also correlated with the development of chronic allograft failure. Renal interstitial fibrosis and tubular atrophy (IFTA).
Treatment of acute renal allograft rejection
Several therapeutic options are available for treatment of AR episodes. Synthetic corticosteroids Treatment of AR with high doses of oral prednisone was effective but with toxic side effects, such as gastrointestinal bleeding and increased susceptibility to infection. To prevent these complications, the treatment was switched to intravenous methylprednisolone. In comparison of the two regimens revealed that both glucocorticoids are equally successful in reversing AR. However, pulse therapy with intravenous methylprednisolone is associated with fewer side effects than oral prednisone.
The therapeutic effects of synthetic steroids for the treatment of acute
renal allograft rejection are attributed to their anti-inflammatory and
immunosuppressive effects. The actions of steroids are mediated by the intracellular glucocorticoid receptor. Polyclonal and monoclonal antibodies
anti-thymocyte globulin (ATG), which obtained from horses or rabbits immunized with human lymphocytes, as a treatment of allograft rejection. ATG therapy causes depletion of circulating T cells and other leukocytes through various mechanisms, including antibody and complement dependent lysis and the induction of apoptosis. ATG is an effective treatment of AR with high graft survival rates. However, ATG can induce complications, such as leukopenia, cytokine release syndrome,and viral infections. ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR.
Steroid resistance AR
Most of acute renal allograft rejection episodes can be adequately
treated with high-dose corticosteroids. However, in nearly 25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone. In such cases of steroid resistance, the patient requires more vigorous immunotherapy to reverse the AR episode. Renal allograft recipients with steroid refractory rejection are treated with ATG, which results in a salvage rate of 70 to 90%.
Diagnosis of steroid resistance relies on post transplantation follow up of clinical parameters reflecting renal allograft function. An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to pre-rejection baseline level after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy. The minimal time for assessment of the response to steroids is five days after initiation of the pulse therapy. The 5 days’ time is considered
The control time to assess the action of steroids either responsive or resistant.
Assessment of risk for steroid resistance
Knowing of steroid resistance at the time of biopsy could prevent
unnecessary exposure to high-dose corticosteroid therapy.
In Conclusion, Resistance to steroid therapy is a complex and multifactorial condition, in which both immunological and non-immunological factors can be involved. The response to high-dose corticosteroid therapy for the treatment of acute renal allograft rejection depends on the characteristics of T cells and macrophages infiltrating the renal allograft. These findings indicate that steroid resistance resides in specific cell populations and is not a feature of all lymphocytes.
Nandita Sugumar
2 years ago
Summary
Introduction
Immunosuppressive drugs have been used to decrease the incidence of acute rejection in transplant recipients. Short term survival of grafts have grown better. However, risk of graft failure remains.
Mechanism of steroid action
Steroids have been used as part of maintenance immunosuppressive therapy. High doses of steroids can be used to reverse acute renal allograft rejection. However, effects of steroids are not all good. Some of the adverse effects from their use include gastrointestinal hemorrhage, and increased susceptibility to infection. Oral to IV steroids change can possibly reduce risk of these effects.
IV pulse therapy of high dose methylprednisolone can be used as first line therapy for AR.
Steroids have important immunoregulatory effects. These include anti-inflammatory effects. Direct and indirect regulation of immune related gene transcription. Inflammatory genes are suppressed by glucocorticoids. These genes are activated during acute rejection and thus their downregulation, along with the increase of expression of anti-inflammatory cytokines and transcription mediators allows steroids to be an effective tool against AR.
Steroid resistance
Steroids bring about their effects through intracellular glucocorticoid receptor(GR), which is a ligand dependent transcription factor of nuclear receptors. Signaling pathways of GC-GR complex inhibits transcription of pro inflammatory molecules, such as cytokines, chemokine, adhesion molecules, inflammatory enzymes, and receptors of different types and kinds. Alteration in the molecule mechanisms of GR signaling is what leads to steroid resistance.
Steroid resistance is a major issue since AR is often treated with high dose corticosteroids. However, when the patient is resistant to these drugs, it puts the graft at danger. In case of resistance, the patient needs to be treated with even more intensive immunotherapy to rescue the graft back from rejection. ATG is often used with good outcome in steroid resistant patients. Diagnosis of resistance is often made post transplant when the patient does not respond to steroid pulse therapy. This is evidenced by the fact that serum creatinine does not return to within 120% if pre-rejection baseline value within 14 days of starting steroid therapy.
It is necessary to keep in mind that incomplete restoration of graft function can lead to chronic damage and worse outcome.
Assessment of steroid resistance
Biomarkers of steroid resistance are the biomarkers for the molecular and cellular mechanisms involved in graft survival. These include immunological and non-immunological biomarkers.
Immune biomarkers include the following :
Cytotoxic T lymphocytes – Increased in steroid resistance
NK cells – increased
B lymphocytes – increased
Macrophages – increased
Non-immunological biomarkers for steroid resistance include – High intragraft expression of metallothioneins and tissue inhibitor of metalloproteinase 1 during acute renal allograft rejection.
Combination of immune and non-immune biomarkers enhance sensitivity and specificity, allowing better risk assessment of steroid resistance in patients with AR.
Mohammed Sobair
3 years ago
Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection
Summary
Introductions:
Acute Rejection is the main cause of graft loss. Despite the success of renal
transplantation, approximately 40% of renal allografts fail within the first 10 years.
Though outcome of graft survival improved with new IS its still has long term effect on
graft survival.
At 10yerrs 50% of DDT have graft loss and 30% of LDT have.
Cause of 10%of graft failure.
AR correlates with a significant reduction in long-term allograft survival.
AR is also correlated with the development of chronic allograft failure.
Various parameters of AR determine the level of risk for adverse graft outcome including
the timing, recurrence, severity, and therapy sensitivity of the AR episode.
Treatment of AR:
Synthetic corticosteroid:
Intravenous is preferred to oral in treatment of AR.
Polyclonal and monoclonal antibodies:
ATG therapy causes depletion of circulating T cells and other leukocytes through various
mechanisms, including antibody- and complement dependent lysis and the induction of
apoptosis.
ATG is an effective treatment of AR with high graft survival rates.
However, ATG can induce complications, such as leukopenia, cytokine release
syndrome, and viral infections.
Due to the risk of complication only used for recurrent and steroid resistant AR.
Steroid resistance:
The majority of acute renal allograft rejection episodes can be adequately treated with
high-dose corticosteroids.
However, in approximately 25 to 30% of the patients the rejection episode cannot be
reversed with corticosteroid therapy alone.
Renal allograft recipients with steroid-refractory rejection are generally treated with ATG.
An AR episode is considered steroid resistant when the patient’s serum creatinine levels
do not return to within 120% of the pre-rejection baseline value after pulse therapy with
corticosteroids within 14 days after the start of the steroid therapy. At that point ATG
treatment is generally required.
The first few days after the start of the steroid treatment are crucial. Analysis of
creatinine courses of steroid-resistant and steroid-responsive cases revealed that the
minimal time period for assessment of the response to steroids is five days after
initiation of the pulse therapy.
Changes in serum creatinine levels were similar between patients with steroid
responsive and steroid resistant AR until day 5, at which time the responders showed
a significant decrease in serum creatinine, while the creatinine level of non-responders.
remained high.
This 5-day period is also the average time delay used by clinicians before considering a
rejection as being steroid resistant.
STEROID IMMUNMODULATION:
Genes activated during AR:
Gene in using cytokins, chemokines, adhesions molecules and inflammatory enzymes.
Gcs increase expression of anti-inflammatory cytokines and transcription mediators,
prevention of leukocyte migration.
Induction of cell death of lymphocytes.
Effect on growth and lineages commitment. Of T. Lymphocytes
Corticosteroidsignaling:
The actions of GCs are mediated by the intracellular glucocorticoid receptor (GR), a
ligand-dependent transcription factor of the nuclear receptor superfamily, which is
ubiquitously expressed in most human cells.
The genomic structure of the GR consists of 9 exons.
Alternative splicing in exon 9 generates two C-terminal receptor isoforms, termed GRα
and GRβ.
The predominantly expressed GRα is activated by GC binding and mediates most of the
known immunomodulatory effects.
The signaling pathways of the GC-GR complex inhibit the transcription of pro-
inflammatory molecules, including cytokines, chemokines, adhesion molecules,
inflammatory enzymes, and receptors. Alterations in the molecular mechanisms of GR
signaling may lead to steroid resist .
steroidresistance:
Clinical and pathologic indicators of steroid resistant rejection:
. Several parameters have been associated with response to steroid treatment:
Acute vascular rejection.
the presence of mononuclear cells at endothelial cells of large and small vessels in the
graft.
an immune response directed against the microvasculature.
moderate to severe microvascular destruction respond less adequately to steroid
therapy compared to patients with only mild destruction of the microvascular
endothelium.
extensive leukocyte infiltration into the peritubular capillaries.
Circulating leukocytes target HLA molecules expressed on the PTC, which results into
cellular rejection. In addition, the HLA molecules can also be targeted by donor-specific
antibodies, leading to local complement activation and humoral rejection.
C4d deposition in PTC has been associated with steroid resistance.
prognostic biomarkers for steroid resistant rejections:
Biomarkers for molecular and cellular mechanisms involved in graft survival and
medication responsiveness could provide complementary parameters.
Immune biomarkers:
Resistance to GCs has been associated with increased expression of cytotoxic T
lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage.
Cytotoxic T lymphocytes and NK cells:
the presence of T lymphocytes. The extent of CD8+ T cells infiltration within the allograft
was correlated with response to AR treatment with GCs.
Furthermore, relatively high FasL mRNA expression and dense granulysin staining renal
allograft biopsies, as well as low FoxP3 expression in urinary sediments.
B lymphocytes. The extent of B cell infiltration within the renal allograft was shown to
discriminate between steroid resistant and steroid response AR episodes. Patients with
steroid-refractory AR expressed increased intragraft levels of the B cell marker CD20.
immunostainings for CD20 revealed significant differences in the level of B cell
infiltration during AR, which correlated with response to steroid therapy and long-term
graft outcome.
Macrophages:
Macrophages derived from the transplant recipient are an important aspect of the
immune infiltrate during Ar. Macrophage infiltration within the kidney transplant has been
related with response to GC treatment.
challenges for biomarker identification:
in clinical study showed that a combination of T cell activation markers CD25:CD3ε ratio
and lymphocyte activation gene-3 (LAG-3) offers an improved prognostic value for
assessing steroid response, compared to conventional clinical parameters and
histopathologic assessment.
Non-immunological biomarkers:
A relatively novel finding is the link between zinc regulation and resistance to anti-
rejection treatment with steroids.
Relatively high intragraft expression of metallothioneins (MT) and tissue inhibitor of
metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with
steroid resistances.
Combination of immune- and non-immune biomarkers:
Combination of biomarkers in a multivariate prediction model could enhance sensitivity
and specificity, and facilitate risk assessment of steroid resistance in patients suffering
from AR.
Glucocorticoid receptor expression:
the anti-inflammatory and immunosuppressive actions of GCs are mediated by the
ligand-dependent GR. Consequently, differences in response to treatment with GCs may
be explained by variations in GR expression. Decreased GR expression has been
implicated as a cause of steroid resistance in a wide variety of diseases, including
nephrotic syndrome, acute lymphoblastic leukemia, and asthma. The observed
differences in GR expression between responders and no responders might be a
reflection of varying levels of GR autoregulation.
differences in treatment response may also be explained by genetic variability. Mutations
in the GR gene (NR3C1, nuclear receptor subfamily 3, group C, member 1) can affect
the functionality of the GR and result in steroid resistance.
Clinical implications:
steroid resistance is a complex and multifactorial condition, in which both immunological
and non-immunological factors can be involved.
Investigations of immune-related biomarkers revealed that both T cells and macrophages
play an important role in the response to steroid therapy.
Combined, these findings indicate that steroid resistance resides in specific cell
populations.
This may guide the therapeutic approaches for treatment of steroid-refractory AR
episodes. Furthermore, Zinc regulation may play a role in the response to steroid
therapy during AR.
Kidney transplant recipients who express high intragraft levels of MT and TIMP1 during
AR might benefit from extra zinc intake for optimal GC signaling.
multivariate prediction model, containing biomarkers related to different aspects of GC
signaling, offers a superior prognostic value for assessing steroid response compared to
conventional clinical parameters and histopathologic assessment, and to single
biomarkers.
Such a multivariate approach could identify patients with insufficient response to anti-
rejection treatment with GCs, who would benefit from immediate ATG treatment.
Future perspectives:
Validations of the prognostic value of biomarkers.
MicroRNA expression as a novel biomarker for response to steroid.
Non-invasive methods for monitoring of graft outcome.
Conclusion:
Resistance to steroid therapy is a complex and multifactorial condition, in which both
immunological and non-immunological factors can be involved.
Zinc regulation and drug metabolism may play a role in the response to steroid therapy
during acute renal allograft rejection. Therefore, kidney transplant recipients may benefit
from additional zinc intake to optimize GC signaling.
A multivariate prediction model, containing biomarkers related to different aspects of GC
signaling, offers the best prognostic value for assessing steroid response.
How would this study change your practice?
Adoption of different biomarker can help in prediction of early resistance to Gcs.
So avoidance of delay of initiation of ATG and salvage of graft.
Abdullah Raoof
3 years ago
§ the majority of acute AR episodes can be adequately treated with
§glucocorticoid therapy, 25 to 30% of the rejection episode cannot be reversed with glucocorticoids alone.
§ Prediction of steroid resistance
o could prevent unnecessary exposure to high-dose cor ticosteroid
otherapy and
o avoid the development and progression of irreversible nephron.
§ acute rejection (AR) is a main risk factor for adverse graft outcome. AR is primarily a cellular immune which generally occurs during the early post-transplant period, with the highest risk in the first 3 months.
Impact of acute rejection on graft outcome
The introduction of immunosuppressive medications has reduced the incidence of AR from over 80% to below 15% .
the short-term survival of kidney grafts has substantially improved, with one-year graft survival rates in excess of 90% in current daily practice but the long-term graft outcome improved only marginally over the past two decades. Even after the introduction of immunosuppressive medication, AR
continues to be a primary cause of renal allograft failure.
the occurrence of AR correlates with a significant reduction in long-term allograft survival.
Chronic allograft nephropathy is the most prevalent cause of chronic allograft failure after the first post-transplant year .
Analyses of factors related to the development of IFTA revealed AR as one of the primary risk factors
Various parameters of AR determine the level of risk for adverse
graft outcome including
§ the timing,( Risk increases as the time between engraftment and occurrence of AR increases)
§ recurrence,( repeated AR episodes are at greater risk of adverse graft outcome)
§ severity, ( vascular rejection (Banff grade II) have a higher risk compared to tubulointerstitial rejection (Banff grade I)
§ therapy sensitivity of the AR episode .(rejection episodes unresponsive to AR treatment have been associated with increased risk of allograft failure )
Treatment of acute renal allograft rejection
Synthetic corticosteroids
The first time to use of immunosuppressive drugs for the treatment of acute RA was in 1960
Nowadays, intravenous pulse therapy with high-dose methylprednisolone has become the first-line therapy for AR in most medical centers.
ATG therapy causes depletion of T cells through various mechanisms, including
§ antibody- and complement dependent lysis
§ the induction of apoptosis .
ATG is an effective treatment of AR with high graft survival rates .\
ATG has complications, such as leukopenia, cytokine release syndrome, and viral infections [
Due to the risk of complications ATG is mainly used for the treatment of
§ steroid-resistant AR
§ recurrent AR.
The murine derived Muromonab- CD3 (OKT3) is amonoclonal antibody based treatment directed against the CD3 molecule,
Due to its lower efficacy and higher incidence of side effects compared to ATG treatment, OKT3 has been with drawn from the market and is no longer in clinical use.
Immunoregulatory effects of corticosteroids
The therapeutic effects of synthetic GCs for the treatment of acute renal allograft rejection are attributed to their anti-inflammatory and immunosuppressive effects.
These protective effects on the allograft are mainly obtained through direct and indirect regulation of immune-related gene transcription. GCs regulate approximately 20% of all genes expressed in leukocytes.
The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes. Besides the downregulation of pro-inflammatory genes, GCs increase the expression of anti-inflammatory cytokines and transcription mediators
Steroid resistance
The majority of acute renal allograft rejection episodes can be adequately treated with high-dose corticosteroids. However, in approximately 25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone.
In steroid resistance, the patient requires more rigorous immunotherapy to reverse the AR episode.
Renal allograft recipients with steroid-refractory rejection are generally treated with ATG, which results in a salvage rate of 70 to 90% .
An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids
within 14 days after the start of the steroid therapy . At that point, ATG treatment is generally required.
The first few days after the start of the steroid treatment are crucial.
Analysis of creatinine courses of steroid-resistant and steroid-responsive cases revealed that
the minimal time period for assessment of the response to steroids is five days after initiation of the pulse therapy.
Changes in serumcreatinine levels were similar between patients with steroid responsive
and steroid resistant AR until day 5, at which time the responders showed a significant decrease in serum creatinine, while the creatinine level of non-responders remained high. This 5-day period is also the average time delay used by clinicians before considering a rejection as
being steroid resistant .Incomplete restoration of graft function in steroid resistant rejectionmay lead to progression of chronic damage to the graft and has a detrimental effect on graft outcome
Assessment of risk for steroid resistance
Clinical and pathologic indicators of steroid resistant rejection
Several parameters have been associated with response to steroid treatment.
§ Acute vascular rejection
§ the presence of mononuclear cells at endothelial cells of large and small vessels
§ the presence of an immune response directed against the microvasculature.
§ Patients with moderate to severe microvascular destruction respond less adequately to steroid therapy
§ more extensive leukocyte infiltration into the peritubular capillaries (PTC).
§ C4d deposition in PTC has been associated with steroid resistance.
§ increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage signatures . steroid resistance may reside in specific lymphocyte populations, with activat ed T cell populations as the prime candidate.
§ no single biomarker has been able to predict the response to steroid treatment with both high sensitivity and high specificity
§ Decreased GR (glucocorticoid receptor )expression has been implicated as a cause of steroid resistance in a wide variety of diseases.
Clinical implications
steroid resistance is a complex and multifactorial condition, in which both immunological and non-immunological factors can be involved. both T cells and macrophages play an important role in the response to steroid therapy. Zinc regulation may play a role in the response to steroid therapy during AR. Kidney transplant recipients who express high intra graft levels of MT and TIMP1 during AR might benefit from extra zinc intake for optimal GC signaling.
Innocent lule segamwenge
3 years ago
Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection
Introduction
Renal transplant has been a successful treatment improving the life expectancy of patients with ESRD.
40% of transplants still fail within the first 10 years.
Acute rejection is the major reason for the vast majority of graft dysfunction.
AR is diagnosed using both clinical and histological parameters.
Clinical parameters range from asymptomatic to significant creatinine rise and proteinuria.
No clinical biomarkers for AR.
Response to antirejection treatment is difficult to measure. AR impact on graft outcomes
Immunosuppressive medications have improved AR from over 80% in the 1960 to 15% in current time.
Long-term graft outcomes still poor.
Graft loss 50% for deceased donor and 30% living donor 10 years post-transplant.
AR episodes associated with reduced graft survival.
AR is the main risk factor for renal interstitial fibrosis and tubular atrophy (IFTA).
More frequent episodes of AR cause worse graft outcomes.
AR resistant to treatment increases risk of graft failure. AR treatment
Current immunosuppressive medication work mainly by supressing T cell function and activation. Synthetic corticosteroids
Iv pulse therapy with high dose methylprednisolone is first line treatment for AR.
Work by regulating gene transcription in leukocytes
Suppresses inflammatory genes activated during AR
Increase express of anti-inflammatory genes
Effects on intracellular glucocorticoid receptor, especially GR-alpha Polyclonal and monoclonal antibodies
ATG is serum derived polyclonal antibodies from horses or rabbits immunized with human lymphocytes.
Depletes circulating T cells and other white cells
Induces apoptosis, complement and antibody dependent cell death
Effective treatment for AR with profound complications and infection risk
Used for steroid resistant AR and recurrent AR
OKT3 (murine derived muromonab-cd3) a monoclonal antibody against CD3
No longer on the market due to efficacy and many side effects Steroid resistance
25 to 30% of AR is steroid resistant.
Steroid resistance is failure for creatinine to return to within 120% of baseline value within 14 days of steroid pulse therapy.
Response should be seen 5 days after steroid pulse.
ATG is used to treat renal steroid resistant AR with 70 to90% success. Assessment of risk for steroid resistance Factors associated with steroid resistance
Acute vascular rejection and presence of mononuclear cells at endothelial cells of vessels
Immune response against microvasculature
Extensive leukocyte infiltration in peritubular capillaries.
C4d deposition in PTC Prognostic biomarkers for steroid resistance
Poor prognostic markers
Increased CD8+ and NK cell infiltration
Increased mRNA expression levels of CD8+ and NK
low FoxP3 expression in urinary sediments
Increased graft infiltration with CD20 B lymphocytes and immunoglobulin producing cells
Increased graft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1)
Decreased glucocorticoid receptor expression
Conclusion
There are multiple factors associated with glucocorticoid resistance both immunological and no-immunological factors . Current no commercially available biomarkers for predicting this resistance. However the level cellular infiltration and type of cells on the biopsy can give us practical clues on who is likely to have glucocorticoid resistance.
Ahmed Omran
3 years ago
Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection
Acute rejection is associated with poor graft outcome in form of chronic graft dysfunction and graft loss. Around 25-30% of rejection is not responding to glucocorticoid treatment and has been associated with higher risk of graft failure. ATG is used for treatment of steroid-resistant and recurrent acute rejection episodes.
Steroids regulate 20% of genes expressed in leukocytes, inhibit inflammatory genes activated in rejection eg genes encoding cytokines, chemokines, adhesion molecules and inflammatory enzymes .Also, steroids inhibit leukocyte migration, result in induction of cell death in lymphocytes and have effect on growth and lineage commitment of T cells. They act on glucocorticoid receptor(GR), activating it through removing GR inhibitory complex and enter nucleus after dimerization, where they act on glucocorticoid response elements and lead to increase in anti-inflammatory genes, decrease in pro-inflammatory genes, zinc dependent recruitment of HDAC-2, inhibiting active chromatin leading to decrease in activation of pro-inflammatory genes and decreased cell proliferation by inhibiting MAP kinase. So altered molecular mechanisms of GR signaling can lead to steroid resistance.
Steroid resistant rejection is considered if serum creatinine does not fall to less than 120% of the baseline within 14 days following pulse steroid therapy. The usual period to assess steroid response is 5 days after initiation of pulse steroid treatment. ATG treatment is usually required at this time with 70-90% success rate in reversing rejection. Additional zinc is useful in glucocorticoid signaling.
Steroid resistance is manifested in specific cell populations. Clinical and pathological indicators of steroid resistance include acute vascular rejection, mononuclear cells at endothelial cells of small and large vessels in graft, immune response directed against vasculature, more extensive leukocyte infiltration and C4d deposition in peritubular capillaries. Immunological biomarkers of steroid resistance include increased cytotoxic T lymphocyte – NK cell signature ;increased FasL mRNA, decreased FoxP3 in urine and increased dense granulation stain in biopsy, B lymphocyte signature ;increased CD20 and B lymphocyte associated immunoglobulin in the graft, and intra glomerular and interstitial macrophage signature (CD68) & increased CD25-CD3e ratio and LAG-3 (lymphocyte activationgene-3). Non-immune biomarkers include removal of zinc ion by increased intragraft metallothioneins and TIMP-1 (tissue inhibitor of metalloproteinase-1) and F2R (coagulation factor II receptor). Decreased GR expression has been associated with reduced ratio of GR alpha/ GR beta.
Steroid resistance has multiple factors. T cells & macrophages play important role in steroid response to the rejection.
Impact of study on clinical practice
Kidney biopsy with DSA assay should be undertaken as early as possible when rejection is suspected. In case of no response to steroids within 5 days, possibility of steroid resistance is high and so ATG administration should be considered. Treatment of AMR with IVIG/ plasmapheresis.
nawaf yehia
3 years ago
Article Summary :
Despite the success of renal transplantation, approximately 40% of renal allografts fail within thefirst 10 years, Even after the introduction of immunosuppressive medication, AR continues to be a primary cause of renal allograft failure. Approximately 10% of all graft losses are directly caused by acute renal allograft rejection. In addition, the occurrence of AR correlates with a significant reduction in long-term allograft survival . AR is also correlatedwith the development of chronic allograft failure. Renal interstitial fibrosis and tubular atrophy (IFTA)—which was formerly known as chronic allograft nephropathy (CAN)—is the most prevalent cause of chronic allograft failure after the
first post-transplant year .
Various parameters of AR determine the level of risk for adverse graft outcome including the timing, recurrence, severity, and therapy sensitivity of the AR episode .
Treatment of acute renal allograft rejection : 1]. Synthetic corticosteroids
The first report on the use of immunosuppressive drugs for the treatment of acute renal allograft rejection appeared in 1960 , synthetic glucocorticoids (GCs) are used for both the prevention and treatment of AR . Nowadays, intravenous pulse therapy with high-dose methylprednisolone has become the first-line therapy for AR in most medical centers 2] ATG
ATG
therapy causes depletion of circulating T cells and other leukocytes]. ATG is an effective
treatment of AR with high graft survival rates . However, ATG can induce complications, such as leukopenia, cytokine release syndrome, and viral infections . Due to the risk of complications, ATG is mainly used for the treatment of steroid-resistant AR and recurrent
AR.
Immunoregulatory effects of corticosteroids
The therapeutic effects of synthetic GCs for the treatment of acute allograft rejection are attributed to their anti-inflammatory and immunosuppressive effects. These protective effects on the allograft are mainly obtained through direct and indirect regulation of
immune-related gene transcription. GCs regulate approximately 20% of all genes expressed in leukocytes
The major action of GCs is the:
1] suppression of inflammatory genes that are activated during AR, including
genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory
enzymes ].
2]GCs increase the expression of antiinflammatory cytokines and transcription mediators
3] prevention of leukocyte migration,
4]induction of cell death in lymphocytes
5] effects on the growth and lineage commitment of T cells
Corticosteroid signaling & steroid resistance
The actions of GCs are mediated by the intracellular glucocorticoid receptor (GR) which is ubiquitously expressed in most human cells . The signaling pathways of the GC-GR complex inhibit the transcription of pro-inflammatory molecules, including cytokines,
chemokines, adhesion molecules, inflammatory enzymes, and receptors. Alterations in the molecular mechanisms of GR signaling may lead to steroid resistance.
Although The majority of acute renal allograft rejection episodes can be adequately
treated with high-dose corticosteroids. However, in approximately 25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone .
An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy . in fact the minimal time period for assessment of the response to steroids is five days after initiation of the pulse therapy , at which time the responders showed a significant decrease in serum creatinine, while the creatinine level of non-responders remained high.
Assessment of risk for steroid resistance
predicting resistance could prevent the unnecessary exposure to high doses of steroids and avoid progresssive irreversible nephron loss during the period of ineffective AR therapy with GC alone . pathologic indicators of steroid resistant rejection
Several parameters have been associated with response to steroid treatment.
1] Acute vascular rejection is related to resistance to high-dose steroid therapy
2] presence of mononuclear cells at endothelial cells of large and small vessels in the graft .
3] immune response directed against the microvasculature. Patients with moderate to severe microvascular destruction respond less adequately to steroid therapy compared to patients with only mild destruction of the microvascular endothelium .
4] Extensive leukocyte infiltration into the peritubular capillaries (PTC) .
( Circulating leukocytes target HLA molecules expressed on the PTC, which results into cellular rejection.In addition, the HLA molecules can also be targeted by donor-specific
antibodies, leading to local complement activation and humoral rejection).
5] C4d deposition in PTC
Prognostic biomarkers for steroid resistant rejection
It remains difficult to predict the risk of graft loss and the response to anti-rejection treatment on basis of histopathologic assessment and clinical parameters. Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness could provide complementary parameters for assessing the risk of adverse graft outcome.
Immune biomarkers :
Expression levels of various markers in allograft histopathology , particularly those of allograft-infiltrating inflammatory cell types,were found to be informative with respect to therapy response. Resistance to GCs has been associated with increased expression of :
1/cytotoxic T lymphocyte ( extent of CD 8 + T cells infiltration in allograft )
2/ natural killer (NK) cell
3/ B lymphocyte ( high CD 20 and B lymphocytes associated Ig )
4/ macrophage ( immunostaining for CD 68 )
Challenges for biomarker identification in clinical context
Even though various immunemarkers have been proposed as prognostic biomarkers for graft outcome, clinical interpretation of these findings has proven difficult due to diversity in clinical endpoint definitions and patient cohort characteristics ( type of immnosuppression , time of AR occurence , technique of sample processing and expression analysis ) .
By attempting to overcome such diversities ,the study showed that a combination of T cell activation markersCD25:CD3ε ratio and lymphocyte activation gene-3 (LAG-3) offers an improved prognostic value for assessing steroid response, compared to conventional clinical parameters and histopathologic assessment. These two signal transduction molecules are involved in the regulation of T cells: CD25, the α- subunit of the IL-2 receptor (IL-2R), is an important regulator of T cell survival and proliferation , while the activation-induced LAG-3 is involved in the negative regulation of homeostasis and T cell function .
Non-immunological biomarkers
A relatively novel finding is the link between zinc regulation and resistance
to anti-rejection treatment with steroids. Relatively high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associatedwith steroid resistance
MT are cysteine-rich proteins involved in the regulation of zinc ions , so MT can control cellular zinc distribution such that Increased intragraft MT expression may lead to removal of zinc ions that are normally used in GC signaling . Also he binding of the activated GC-GR complex to GREs relies on two zinc finger motifs .
TIMP1 may diminish the zinc-requiring anti-inflammatory effects of the GR through regulation of the intracellular zinc concentrations .
Coagulation factor II receptor (F2R) is a regulator of numerous intracellular
signaling pathways, Differences in F2R may influence the pro- and antiinflammatory
effects of GCs . This can be implicated clinically by giving additional Zinc intake to enhance GC signalling in kidney transplant recipients experiencing AR with the finding of high levels of intragraft expresssion of MT & TIMP1 .
Multivariate analysis of the proposed biomarkers revealed a prediction model that contains both immune (CD25:CD3ε ratio, LAG-3) and non-immune (MT-1, TIMP1, F2R) biomarkers which offers a superior prognostic value for assessing responsiveness to GC therapy compared to both conventional clinical and histopathologic indicators as well as single biomarkers.
Glucocorticoid receptor expression
The anti-inflammatory and immunosuppressive actions of GCs are mediated by the ligand-dependent GR. Consequently, differences in response to treatmentwith GCsmay be explained by variations in GR expression. however , Further studies will be needed to confirm the role of the GR in transplant recipients with GC resistance .
How this article might change my practice ?
knowing that 25 – 30 % of rejecton episodes cannot be reversed with CG alone ,having a partial responce after 5 days of starting CG Rx , having histological criteria that might predict steroid non responce should all make us more aware about sterod resistance and thence to consider other therapy .
MOHAMED Elnafadi
3 years ago
Despite the success of renal transplantation, approximately 40% of renal allografts fail within the first 10 years, and a shortage of donors hampers the number of transplants performed each year. These limitations stress the need to improve long-term graft survival and prevent adverse graft outcome. 40% of renal allograft is not functioning within the first 10 years.
acute cellular rejection diagnosed clinically or histopathologically is the major risk factor for poor allograft function.
Renal transplant recipients can still develop episodes of acute allograft rejection despite optimization of human leukocyte antigen (HLA) compatibility and application of induction therapy and maintenance immunosuppression. Several therapeutic options are available
for the reversal of AR episodes.
Treatment of acute renal allograft rejection
Synthetic corticosteroids high doses of oral prednisone was found to potentially induce toxic side effects, such as gastrointestinal hemorrhage and increased susceptibility to infection. To prevent these complicaions, the treatment was switched from oral prednisone to intravenous application of methylprednisolone, Nowadays, intravenous pulse therapy with high-dose methylprednisolone has become the first-line therapy for AR.
Polyclonal and monoclonal antibodies
ATG is used for the treatment of steroid-resistant AR and recurrent AR, induce complications, such as leukopenia, cytokine release syndrome, and viral infections so its uses is mainly used to SRAR &SRRR.
Immunoregulatory effects of corticosteroids The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes, and increasing the expression of anti-inflammatory cytokines and transcription mediators.
Steroid resistanceAssessment PREDICTING STEROID RESISTANCE DURING BIOPSY PROTECT THE PATIENT AGAINEST HAZARDS OF STEROIDS AND GRAFT LOSS DURING TREATMENT .
Prognostic biomarkers for steroid resistant rejection
Immune biomarkersResistance to GCs has been associated with increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage signatures.
Non-immunological biomarkers new discovery of zinc regulation and resistance to antirejection treatment with steroids. Relatively high intragraft expression of metallothioneins and tissue inhibitor of metalloproteinase-1 during acute renal allograft rejection is associated with steroid resistance.
How would this study change your practice? Identification and early diagnosis of steroid resistant acute rejection will save time for graft funcation plus protecting the patient for hazards of ccs. Novel discovery of zinc will improve the the response of ccs.
Mohamed Essmat
3 years ago
Acute rejection episode is considered steroid resistant when serum creatinine fails to return to 120% of pre-rejection baseline within 14 days after pulse steroids. Steroid resistant rejection is a complex condition, Around 25% of recipients may have rejection episodes that are not reversed with steroids thus need more potent immunosuppression. Prediction of steroid resistance at time of biopsy allows avoiding exposure to high dose steroids as well as Development and progression of graft damage .
Moderate to severe microvascular destruction responds less adequately to steroid therapy.
Extensive leucocyte infiltration into peritubular capillaries associated with steroid resistance.
Acute vascular rejection is related to resistance to high dose steroid.
Presence of mononuclear cells at endothelial cells of large and small vessels in the graft associated with steroid resistance.
Resistance to Steroids is associated with increased expression of cytotoxic T lymphocyte, NK cells, B lymphocytes and macrophage signatures.
There is no single biomarker that can predict the response to steroid treatment.
Combination of biomarkers could improve sensitivity, specificity and predict the response to GC in treatment of acute rejection.
Recipients with acute rejection may benefit from extra zinc intake which may have a role in response to steroid therapy; That’s a point that may affect my future practice , as well as anticipating those who may have steroid resistant rejection.
AMAL Anan
3 years ago
How would this study change your practice?
* Steroid resistance AR occurs after 5 days of start treatment especially if creatinine remains high after pulse steroid therapy.
* Use of zinc may help in steroid resistance .
* ATG used for treatment of steroid resistance rejection, so we can start with steroid for short period, if no response shift to ATG and when biopsy confirm ABMR so proceed to plasma exchange and IVIG with monitoring of DSAs.
* Strict examine graft biopsy for high risk steroid resistance rejection as vascular rejection, micro vascular inflammation and C4d deposition.
* Not all AR respond to steroid.
* Using of both immune and non-immune biomarkers to improve sensitivity and specificity of risk assessment of steroid resistant AR.
References:
1.Z.A. Massy, C. Guijarro, M.R. Wiederkehr, J.Z. Ma, B.L. Kasiske, Chronic renal allo- graft rejection: immunologic and nonimmunologic risk factors, Kidney Int. 49 (2) (1996 Feb) 518–524.
2. H.U.Meier Kriesche,A.O.Ojo,J.A.Hanson,D.M.Cibrik,J.D.Punch,A.B.Leichtman, et al., Increased impact of acute rejection on chronic allograft failure in recent era, Transplantation 70 (7) (2000 Oct 15) 1098–1100.
3. H.I. Feldman, R. Gayner, J.A. Berlin, D.A. Roth, R. Silibovsky, S. Kushner, et al., De- layed function reduces renal allograft survival independent of acute rejection, Nephrol. Dial. Transplant. 11 (7) (1996 Jul) 1306–1313.
4. J.E. Leggat Jr., A.O. Ojo, A.B. Leichtman, F.K. Port, R.A. Wolfe, M.N. Turenne, et al., Long-term renal allograft survival: prognostic implication of the timing of acute re- jection episodes, Transplantation 63 (9) (1997 May 15) 1268–1272.
5.B.L. Kasiske, M.A. Andany, B. Danielson, A thirty percent chronic decline in inverse serum creatinine is an excellent predictor of late renal allograft failure, Am. J. Kid- ney Dis. 39 (4) (2002 Apr) 762–768.
AMAL Anan
3 years ago
-Please give a summary of this article :
*Since the first successful transplantation performed in 1954 , kidney allograft transplantation has become the preferred renal replacement therapy for patients suffering from end-stage renal disease. At present, more than 36,500 kidney transplantations are performed annually in Europe and the United States.
* AR was the most important cause of kidney transplant loss. Only 40% of renal allograft recipients had a functioning graft at one
year after transplantation . The introduction of immunosuppressive medications and refinement in treatment regimens during the following decades has reduced the incidence of AR from over 80% in the 1960s to below 15% nowadays . Over the same period, the short term survival of kidney grafts has substantially improved, with one-year graft survival rates in excess of 90% in current daily practice.
* Various parameters of AR determine the level of risk for adverse graft outcome including the timing, recurrence, severity, and therapy
sensitivity of the AR episode. Risk of graft failure increases as the time between engraftment and occurrence of AR increases, and is most pronounced with late episodes.
* Treatment of acute renal allograft rejection:
– Synthetic corticosteroids .
– Polyclonal and monoclonal antibodies .
* Immunoregulatory effects of corticosteroids :
– anti-inflammatory and immunosuppressive effects.
– The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokine, adhesion molecules, and inflammatory enzymes . Besides the down-regulation of pro-inflammatory genes, GCs increase the expression of anti-inflammatory cytokines and transcription mediators.
-The major action of corticosteroids is the indirect suppression of pro-inflammatory genes that are activated during AR.
-The majority of acute renal allograft rejection episodes can be adequately treated with high-dose corticosteroids. However, in approximately 25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone . Similarly, poor or no response to steroid therapy for AR reversal also occurs in recipients of other solid organ transplants, including liver, lung and cardiacallografts .In such cases of steroid resistance, the patient requires more rigorous immunotherapy to reverse the AR episode. Renal allograft recipients with steroid-refractory rejection are generally treated with ATG, which results in a salvage rate of 70 to 90%.
*** Assessment of risk for steroid resistance:
– Clinical and pathologic indicators of steroid resistant rejection.
– Prognostic biomarkers for steroid resistant rejection : • Immune biomarkers.
• Cytotoxic T lymphocytes and NK cells.
• B lymphocytes.
• Macrophages.
• Non- immunological biomarkers.
* Glucocorticoid receptor expression:
As described in a previous section, the anti-inflammatory and immunosuppressive actions of GCs are mediated by the ligand-dependent GR.
Consequently, differences in response to treatment with GCs may be explained by variations in GR expression. Decreased GR expression has been implicated as a cause of steroid resistance in a wide variety of diseases, including nephrotic syndrome , acute lymphoblastic leukemia , and asthma.
* Clinical implications
The data discussed in this review demonstrate that steroid resistance is a complex and multifactorial condition, in which both immunological and non-immunological factors can be involved. Investigations of immune-related biomarkers revealed that both T cells and macrophages play an important role in the response to steroid therapy. Combined, these findings indicate that steroid resistance resides in specific cell populations. This may guide the therapeutic approaches for treatment of steroid-refractory AR episodes. Furthermore, Zinc regulation may play a role in the response to steroid therapy during AR. Kidney transplant recipients who express high intragraft levels of MT and TIMP1 during AR might benefit from extra zinc intake for optimal GC signaling.
References
[1] J.P. Merrill, J.E. Murray, J.H. Harrison, W.R. Guild, Landmark article Jan 28, 1956:
successful homotransplantation of the human kidney between identical twins. By John P. Merrill, Joseph E. Murray, J. Hartwell Harrison, and Warren R. Guild, JAMA 251 (19) (1984 May 18) 2566–2571.
[2] A. Lennerling, C. Loven, F.J. Dor, F. Ambagtsheer, N. Duerinckx, M. Frunza, et al., Living organ donation practices in Europe – results from an online survey, Transpl. Int.
26 (2) (2013 Feb) 145–153.
[3] J.J. Song, J.P. Guyette, S.E. Gilpin, G. Gonzalez, J.P. Vacanti, H.C. Ott, Regeneration
and experimental orthotopic transplantation of a bioengineered kidney, Nat. Med. 19 (5) (2013 May) 646–651.
[4] S. Hariharan, M.A. McBride, L.E. Bennett, E.P. Cohen, Risk factors for renal allograft
survival from older cadaver donors, Transplantation 64 (12) (1997 Dec 27)
1748–1754.
[5] G.M. Fleming, Renal replacement therapy review: past, present and future, Organogenesis 7 (1) (2011 Jan) 2–12.
[6] L.D. Cornell, R.N. Smith, R.B. Colvin, Kidney transplantation: mechanisms of rejection and acceptance, Annu. Rev. Pathol. 3 (2008) 189–220.
[7] M. Eikmans, D.L. Roelen, F.H.J. Claas, Molecular monitoring for rejection and graft
outcome in kidney transplantation, Expert Opin. Med. Diagn. 2 (12) (2008 Dec
1) 1365–1379.
Manal Malik
3 years ago
Introduction:
Approximately 40% of renal allografts fail within the first 10 years, despite the success of renal transplantation. The occurrence of acute rejection is a dominant risk factor for adverse graft outcomes.
AR is a primary cellular immune response directed against mismatch donor antigens present on the cell allografts, with a higher risk in the first 3 months.
Diagnosis of AR relies on clinical parameters and histopathologic assessment of kidney biopsy samples.
However, once AR is diagnosed, it is difficult to predict the response to ant-rejection treatment based on clinical parameters and histopathologic assessment. The availability of biomarkers could provide complementary parameters for assessing the risk of adverse graft outcomes. Impact of acute rejection on graft outcome:
Approximately 10% of all graft losses are directly caused by acute renal allograft rejection. The occurrence of AR correlates with a significant reduction in long-term allograft survival.
Parameters of AR determine the level of risk for adverse graft outcomes, including the timing, recurrence, severity, and therapy sensitivity of the AR episode [23]. The risk of graft failure increases as the time between engraftment and occurrence of AR increases,
patients with acute vascular rejection (Banff classification grade II) have a higher risk of graft failure compared to patients with (Banff classification grade I). Treatment of acute renal allograft rejection:
1-: Synthetic corticosteroid:
used for both the prevention and treatment of AR
2-Polyclonal and monoclonal antibodies:
ATG is an effective treatment of AR with high graft survival rates
It is mainly used for the treatment of steroid-resistant AR and recurrent AR.
Immunoregulatory effects of corticosteroids:
Protective effects on the allograft are mainly obtained through direct and indirect regulation of immune-related gene transcription. GCs regulate approximately 20% of all genes expressed in leukocytes.
Inflammatory genes are indirectly regulated through interference with transcription factors and their co-activators.
The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes.
Steroid resistance:
Steroid resistance is considered when the patient serum creatinine does not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy.
5 days after the start of pulse steroid therapy is the minimal time period for assessment of response to steroid.
Steroid resistance rejection treated with ATG
Assessment of risk of steroid resistance:
The impact of steroid-refractory rejection on graft integrity stresses the need for tools to assess the response to AR treatment at an early stage.
1-Clinical and pathologic indicators of steroid-resistant rejection:
Clinical parameters and histopathologic assessment of kidney biopsies remain the gold standard for evaluating short- and long-term graft outcomes.
Parameters associated with poor response to steroid treatment (steroid resistance):
a)acute vascular rejection
b) extensive leukocyte infiltration into the peritubular capillaries (PTC)
c)deposition of c4d into the PTC endothelium, although this association could not be confirmed in a recent study.
d) Moderate to severe microvascular inflammation(extensive leukocyte infiltration of the PTC.
2-Prognostic biomarkers for steroid-resistant rejection
Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness could provide complementary parameters for assessing the risk of adverse graft outcome
a) Immune biomarkers:
Increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage signatures have been associated with steroid resistance rejection.
b) challenges for biomarker identification in a clinical context
clinical interpretation of prognostic biomarkers for graft outcome has been proven difficult
The influence of the inter-study reproducibility of biomarkers are differences in patient cohort characteristics, such as type of immune suppression and the time between transplantation and AR, as well as the techniques used for sample processing and expression analysis.
c) Non-immunological biomarkers
high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection are associated with steroid resistance. Zinc supplementation with steroid therapy may play a role in the response to the treatment of AR
Clinical implication ;
Steroid resistance resides in specific cell populations
Zinc regulation may play a key role in response to steroid therapy in acute rejection
The presence of a multi-variate biomarker model may lead to decreased exposure to high dose steroid therapy & avoid progressive graft loss.
Future perspectives:
Validation of the prognostic value of biomarkers
microRNA expression
Non-invasive methods for monitoring graft outcome
Conclusion:
steroid-resistant rejection is complex and multi-faceted
Include immune & non-immune factors
Occur in specific cell populations and is NOT a feature of all lymphocytes
increased expression of zinc regulating molecules may decrease the zinc requiring the anti-inflammatory effect of steroid therapy
Transplant recipients may benefit from zinc supplementation to enhance GC signaling
A multivariate prediction model including biomarkers is essential to assess the risk of poor graft outcomes.
The topic help me to know more about steroid resistance AR and can be predicted from day 5
zinc supplementation help in steroid resistance AR
Asmaa Khudhur
3 years ago
The occurrence of acute rejection (AR) is a dominant risk factor for adverse graft outcome. AR is primarily a cellular immune response di- rected against mismatched donor antigens present on the cells of the al- lograft ,which generally occurs during the early post-transplant period, with the highest risk in the first 3 months. Reliable and timely detection of AR episodes is important for the prevention of adverse graft outcome. Diagnosis of AR episodes relies on clinical parameters and histopathologic assessment of kidney biopsy samples.
Impact of acute rejection on graft outcome
Various parameters of AR determine the level of risk for adverse graft outcome including the timing, recurrence, severity, and therapy sensitivity of the AR episode .Risk of graft failure increases as the time between engraftment and occurrence of AR increases, and is most pronounced with late AR episodes (occurring 3 months or more after engraftment) .Similarly, patients experiencing repeated AR episodes are at greater risk of adverse graft outcome than those with no or only one episode .In addition, patients with acute vascular rejection (Banff classification grade II) have a higher risk of graft failure compared to patients with acute tubulointerstitial rejection (Banff classification grade I) .Furthermore, rejection episodes unresponsive to AR treatment have been associated with increased risk of allograft failure .
Treatment of acute renal allograft rejection
Synthetic corticosteroids
Polyclonal and monoclonal antibodies
Immunoregulatory effects of corticosteroids
The therapeutic effects of synthetic GCs for the treatment of acute renal allograft rejection are attributed to their anti-inflammatory and immunosuppressive effects. These protective effects on the allograft are mainly obtained through direct and indirect regulation of immune-related gene transcription.
Steroid resistance
Diagnosis of steroid resistance primarily relies on post- transplantation follow-up of clinical parameters reflecting renal allo- graft function. An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy .
Assessment of risk for steroid resistance
1-Clinical and pathologic indicators of steroid resistant rejection:
Acute vascular rejection is related to resistance to high-dose steroid therapy and a subsequent higher chance of graft failure [
unresponsiveness to steroid therapy has been associated with the presence of mononuclear cells at endothelial cells of large and small vessels in the graft
An- other aspect associated with steroid resistance is the presence of an immune response directed against the microvasculature. Patients with moderate to severe microvascular destruction respond less adequately to steroid therapy compared to patients with only mild destruction of the microvascular endothelium .Steroid-refractory AR has been associated with more extensive leukocyte infiltration into the peritubular capillaries (PTC) .
Prognostic biomarkers for steroid resistant rejection
Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness could provide complementary parameters for assessing the risk of adverse graft outcome.
1-Immune biomarkers
a-Cytotoxic T lymphocytes and NK cells.
b-B lymphocytes.
c-Macrophages
2-Non-immunological biomarkers
high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with steroid resistance.
This article help me now to predict steroid resistance AR after 5 days of starting treatment
Know more about GR
Use of zinc may help me in steroid resistance nephrotic syndrome cases in my practice , not only in transplantation.
Ben Lomatayo
3 years ago
Introduction;
At present around 36,500 kidney transplantation are carried world wide[2,3]
Unfortunately 40% of renal allograft is not functioning within the first 10 years
The presence of acute cellular rejection diagnosed clinically( increase in serum creatinine) and histo-pathologically(Bannf criteria) is the major risk factor for poor allograft function[6-10]
Treatment of AR is challenging because it is difficult to predict who will respond to anti-rejection therapy based on clinical & histo-pathologic findings.
Addition of biomarkers may help in evaluating the the risk of poor graft outcomes
This review provide insight about biomarkers of steriod-resistant rejection in kidney transplantation
2. Impact of acute rejection on graft outcome ;
Around 10% of all graft losses occurred as a result of acute rejection[19]
AR is associated with significant reduction in long-term allograft survival[20-30]
3.Treatment of acute rejection ; this is done mainly by immun-osuppressive drugs which are ;
1. Synthetic corticosteriods
It was first used in 1960[47]
IV pulse therapy is favoured over the oral therapy due to minimal side effects such as GIT hemorrhages & infections[49,52]
2.Polyclonal antibodies;
ATG derived from horses or rabbits[57-60] ; it causes T lymphoctes depletion by many mechanism e.g. complement-dependent lysis and apoptpsis
Leucopenia, thrombocytopnenia, cytokine release -syndrome , viral infections are the major problems[60-63]
Indications ; induction therapy, treatment of steroids-resistant rejection, recurrent episodes of AR
3.Monoclonal antibodies ;
Murine-derived Muromonab-CD3(OKT3) ; Modulates TCR resulting in depletion of T lymphocytes
The indication is similar to ATG[66-68]
No longer available due low efficacy & more side effects profiles
4.Immuno-regulatory effects of corticosteroids ;
GC regulates approximately 20% of gene expressed in leukocytes[71]
Inflammatory genes are indirectly regulated by interference with transcription factors and their co-activator
Suppression of inflammatory genes activated during rejection[72-75]
Increase expression of anti-inflammatory cytokines & transcription mediators[72,76]
other mechanisms during rejection are prevention of leukocytes migration,apoptosis of T lymphocytes, and affects on the the growth and lineage commitment of T lymphocytes[77-80]
1.Cortico-steroid signaling ; through glucocorticoid receptor(GR) which consist of ;
9 exons
Two C-terminal receptor isoforms ; 1.GR A(alpha) 2. GR B(Beta)[81]
GR alpha is predominantly expressed, activated GC binding, mediates most of the immune-medulatory effects
GR beta ; express different terminal C region , inhibit GC binding( negative effect), induced by cytokines[83- 86]
GR has 3 domains ;
N terminal domain(NTD) ; target gene activation and interact with other transcription factors
Central DNA-binding domain(DBD) ; bind with GRE(glucocorticoid response element) in the promoter region of the target genes
Ligand-binding domain(LBD); contain specific GC- binding site and heat shock protein( Hsp) [87-90]
GC-GR increases the transcription of inhibitor of kB and MAP kinase phosphatase-1, which inhibit NF-kB & mitogen-activated protein(MAP) kinase[73,78]
GC-GR complex recurits histone decactylation(HDAC)-2 to the activated inflammatory gene complex, resulting in deacetylation of nuclear histones and inhibition of pro-inflammatory gene transcription[72-75]
Alteration in the molecular mechanisms of GR signaling may lead to steroid resistance.
5. Steroid resistance ;
Defined as failure of Cr to return to within 120% of the baseline within 14 days after pulse steriod therapy[7,107-109]
Steroid-resistance is an indication for ATG
25-30% of cases of acute rejection are resistant to steroid treatment alone[42,96.101]
Those patients are treated with ATG and it is successful in 70-80%[70,105,107]
It takes 5 days to assess steroids responsiveness after pulse steroid therapy ; responders will show significantly decrease in Cr while in non-respnders Cr remained high[110]
Steroid-resistance is associated progressive chronic damage to the allograft and poor allograft outcomes[40,42,98,111]
6.Assessment of risk for steroid resistance ;
1.Clinical & pathologic indicators of steroid resistance rejection ; the gold standard A) Clinical ; Cr remains high
B) Histopathology ;
Acute vascular rejection(IIB)[108,112,113]
Mono-nuclear cells at vascular endotheilum
Moderate to severe micro-vascular inflammation(extensive leukocyte infiltration of the ptc)[113]
C4d deposition in the ptc ?[113]
2.Prognostic biomarkers for steroid resistant rejection ; this provide complementary parameters for evaluating the risk of allograft loss.
A) Immune biomarkers ; the presence of these cells in allograft biopsy are associated with steroid resistant rejection[99,100,109,120,121,129,130]
Cyto-toxic T lymphocytes & NK cells
B lymphocytes
Macrophages
Challenges with the use of immune biomarker ;
Validation
Interpretation
Reproducibility
Inconsistency in the definition of steroid resistant rejection
B) Non-immunological biomarkers ;
High intra-graft expression of metallothioneins(MT)
High intra-graft expression of tissue inhibitor of metalloproteinase-1( TMIP1)
These are associates removal of the zinc irons that are normally complexed in the zinc finger motifs, there by preventing GR binding to GREs & inhibiting the immune-modulatory effect of GC[148,149]
MT may lead to inhibition of anti-inflammatory of GC
TIMP1 may decrease the zinc-requiring anti-inflammatory effect of the GR through regulation of the intracellular zinc concentration
Coagulation factor II receptor(F2R)
Combination of immune & non-immune biomarkers ;
This provide multivariate model that may improve the sensitivity, specificity,& pave the way for risk assessment of steroid resistant rejection
7.Clinical implication ;
Steroid resistance resides in specific cell populations
Zinc regulation may play a key role in response to steroid therapy in acute rejection
The presence of a multi-variate biomarker model may lead to decreased exposure to high dose steroid therapy & avoid progressive graft loss.
8.Future prospective ;
Validation
MicroRNA
Non-invasive monitoring of the graft ; blood & urine
9.Conclusion ;
Steroid resistant rejection is complex and multi-faceted
Include immune & non-immune factors
Occur in specific cell population and is NOT a feature of all lymphocytes
increased expression of zinc regulating molecules may decrease the zinc requiring anti-inflammatory effect of steroid therapy
Transplant recipients may benefit from zinc supplementation to enhance GC signaling
Multivarite prediction model including biomarker is essential to assess the risk of poor graft outcomes.
This article is very helpful , I got 3 take home messages ;
Consideration of steroid resistant rejection after 5 days if Cr remains high after pulse steroid therapy
Careful examination of the allograft biopsy for feautres of high risk for steroid resistant rejection e.g. Vascular rejection, micro-vascular inflammation, C4d deposition
ATG to treat cases of steroid resistant rejection
Zinc may help some patients with steroid resistant rejection
Zahid Nabi
3 years ago
Acute rejection (AR) has negative impact on graft survival. Acute rejection is primarily a cellular
immune response directed against mismatched donor antigens present on the cells of the allograft, occurs during early post transplantperiod, with the highest risk in the first 3 months. Most cases respond adequately to steroid treatment. however, 25-30% of cases are steroid resistant and can’t be recovered with steroids alone. . Diagnosis of AR episodes relies on clinical parameters and histopathologic assessment of kidney biopsy samples. Most patients who develop an AR episode are asymptomatic and present only with an increase in serum creatinine levels as an indicator of a decline in renal function .
It is still difficult to predict the responce to steroid treatment. therefore, there is a persistant need for tools to assess the responce at an early stage.
This review demonstrate that steroid resistance is a complex and multifactorial condition, in which both immunological and non-immunological factors can be involved. Investigations of immune-related biomarkers revealed that both T cells and macrophages play an important role in the response to steroid therapy. Combined, these findings indicate that steroid resistance resides in specific cell populations. Even though the biomarkers described provide a strong prognostic value for predicting a patient’s response to GC therapy, no single biomarker has been able to predict the response to steroid treatment with both high sensitivity and high specificity. This restricted power of single markers is most likely caused by the presence of multiple mechanisms underlying steroid resistance, which is reflected by the observed heterogeneity in transcriptional regulation among AR biopsy samples.
There is a link between zinc regulation and resistance to anti-rejection treatment with steroids.
I doubt we would be able to adopt detection of such sophisticated bio markers at our center and it is not cost effective at all
CARLOS TADEU LEONIDIO
3 years ago
1 – RESUME:
Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection
The occurrence of acute rejection (AR) is a dominant risk factor for adverse graft outcome. AR is primarily a cellular immune response directed against mismatched donor antigens present on the cells of the allograft, which generally occurs during the early post-transplant period, with the highest risk in the first 3 months. Reliable and timely detection of AR episodes is important for the prevention of adverse graft outcome. Diagnosis of AR episodes relies on clinical parameters and histopathologic assessment of kidney biopsy samples. Most patients who develop an AR episode are asymptomatic and present only with an increase in serum creatinine levels as an indicator of a decline in renal function. The cause of graft dysfunction is determined based on nephropathologic criteria and histological assessment of a renal allograft biopsy – The Banff classification.
Even after the introduction of immunosuppressive medication, AR continues to be a primary cause of renal allograft failure. Nowadays, almost all transplant recipients are treated with immunosuppressive drugs to minimize the chance of AR, which act by inhibiting the activation and/or effector functions of T cells. Renal transplant recipients can still develop episodes of acute allograft rejection despite optimization of human leukocyte antigen (HLA) compatibility and application of induction therapy and maintenance immunosuppression. Several therapeutic options are available for the reversal of AR episode:
– Polyclonal and monoclonal antibodies
Anti-thymocyte globulin (ATG), which represents serum-derived polyclonal antibodies obtained from horses or rabbits immunized with human lymphocytes, as a treatment of allograft rejection. ATG therapy causes depletion of circulating T cells and other leukocytes through various mechanisms, including antibody- and complemente dependent lysis and the induction of apoptose. Due to the risk of complications, ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR.
The development of cell-hybridization techniques provided the opportunity to produce monospecific antibodies. The murine derived Muromonab-CD3 (OKT3) is a monoclonal antibody based treatment directed against the CD3 molecule, which is closely associated with the T cell receptor (TCR). OKT3 therapy modulates the TCR, resulting in the depletion of circulating T cells. OKT3 has been used as primary treatment of AR as well as a rescue therapy of steroid resistant AR episodes.
– Synthetics corticosteroids
First report on the use of immunosuppressive drugs for the treatment of acute renal allograft rejection. Pulse therapy with intravenous methylprednisolone is associated with fewer side effects than oral prednisone therapy. Nowadays, intravenous pulse therapy with high-dose methylprednisolone has become the first-line therapy for AR in most medical centers.
The therapeutic effects of synthetic glucocorticoids (GSs) for the treatment of acute renal allograft rejection are attributed to their anti-inflammatory and immunosuppressive effects. These protective effects on the allograft are mainly obtained through direct and indirect regulation of immune-related gene transcription, through of mediated by the intracellular glucocorticoid receptor (GR). GCs regulate approximately 20% of all genes expressed in leukocytes and the major action of GCs is the suppresssion of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes. The major action of corticosteroids is the indirect suppression (trans-repression) of pro-inflammatory genes that are activated during AR.
Majority of acute renal allograft rejection episodes can be adequately treated with high-dose corticosteroids. However, in approximately 25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone. Renal allograft recipients with steroid-refractory rejection are generally treated with ATG, which results in a salvage rate of 70 to 90%. An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy.
Acute vascular rejection is related to resistance to high-dose steroid therapy and a subsequent higher chance of graft failure. Steroid-refractory AR has been associated with more extensive leukocyte infiltration into the peritubular capillaries. Circulating leukocytes target HLA molecules expressed on the peritubular capillaries , which results into cellular rejection. In addition, the HLA molecules can also be targeted by donor-specific antibodies, leading to local complement activation and humoral rejection. The activation of the complement cascade leads to the formation of complement degradation factor C4d, which can covalently bind to the peritubular capillaries endothelium. C4d deposition in peritubular capillaries has been associated with steroid resistance , although this association could not be confirmed in a recent study. Indeed, expression levels of various markers, particularly those of allograft-infiltrating inflammatory cell types, were found to be informative with respect to therapy response. Analyses of AR biopsies obtained from kidney transplant recipients have provided insight into the lymphocyte populations that are associated with poor graft outcome. Resistance to GCs has been associated with increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage signatures, these being considered bioarmarkers.
The data discussed in this review demonstrate that steroid resistance is a complex and multifactorial condition, in which both immunological and non-immunological factors can be involved. Investigations of immune-related biomarkers revealed that both T cells and macrophages play an important role in the response to steroid therapy. Combined, these findings indicate that steroid resistance resides in specific cell populations. Even though the biomarkers described provide a strong prognostic value for predicting a patient’s response to GC therapy, no single biomarker has been able to predict the response to steroid treatment with both high sensitivity and high specificity. This restricted power of single markers is most likely caused by the presence of multiple mechanisms underlying steroid resistance, which is reflected by the observed heterogeneity in transcriptional regulation among AR biopsy samples.
2 – How would this study change your practice?
Corticosteroid resistance screening should be put into practice daily through a protocol of suspicion and investigation.
– I would define as suspicion: the unexplained increase in creatinine (= not related to factors such as immunosuppressant concentration and vascular events) + increase in biomarkers (even knowing that in the single biomarker it has been able to predict the response to steroid treatment with both high sensitivity and high specificity.)
– It would lead to early investigation: biopsy, for the diagnosis of infiltrates: NK cells, Cytotoxic T lymphocytes, B lymphocytes, Macrophages.
Ibrahim Omar
3 years ago
Please give a summary of this article :
acute allograft rejection adversely affect graft function and survival.
most cases of acute allograft rejection responds adequately to steroid treatment. however, 25-30% of cases are steroid resistant and can’t be recovered with steroids alone.
diagnosis of steroid resistance is based on follow- up of renal chemistry post-transplantation.
it is still difficult to predict the responce to steroid treatment. therefore, there is a persistant need for tools to assess the responce at an early stage.
steroid resistance is a complex and multi-factorial state as it includes both immunological and non-immunological factors.
responce to high dose steroids correlates with the expression level and characteristics of T-cells and macrophages infiltrations into the graft.
zinc regulation and drug metabolism may play a role in steroid resistance.
increased expression of zinc regulatory molecules may decrease zinc dependant anti-inflamatory effect of steroid treatment. therefore, kidney graft recipients may benefit from additional zinc to optimize GS signaling.
biomarkers related to different aspects of GS signaling may provide the best prognostic rules for assessing steroid resistance.
How would this study change your practice?
we will try to apply one of the biomarkers related to GS signaling for possible detection of steroid resistance in renal transplant patients.
amiri elaf
3 years ago
Please give a summary of this article
# Approximately 40% of renal allografts fail within the first 10 years, these limitations stress the need to improve long term graft survival and prevent adverse graft outcome.
# Acute rejection is primarily a cellular
immune response directed against mismatched donor antigens present on the cells of the allograft, occurs during early post transplantperiod, with the highest risk in the first 3 months.
# 25 to 30% of the acute rejection episode cannot be reversed with glucocorticoids alone.
# Prediction of steroid resistance could prevent unnecessary exposure to high dose corticosteroid therapy and avoid the development and progression of irreversible nephron.
# Most patients who develope an AR episode are asymptomatic and present only with an increase in serum creatinine levels as an indicator of a decline in renal function .
# Diagnosis of AR episodes relies on clinical parameters and histopathologic assessment of kidney biopsy samples .
# The Banff classification is used to identify and designate the severity of rejection episodes on the basis of the site and degree of inflammation in the transplanted kidney, but it is difficult to predict the response to antirejection treatment.
#This study provides an overview of biomarkers of steroid resistant rejection
in kidney transplantation.
# Various parameters of AR determine the level of risk for adverse graft outcome including the timing, recurrence, severity, and therapy sensitivity of the AR episode.
# Treatment of acute renal allograft rejection:
* Immunosuppressive medication is a cornerstone in the prevention of transplant rejection, it act by inhibiting the activation and/or effector functions of T cells.
* Renal transplant recipients can still develop episodes of acute allograft rejection despite optimization of human leukocyte antigen (HLA) compatibility and application of induction therapy and maintenance immunosuppression.
#Several therapeutic options are available for the reversal of AR episodes.
# Synthetic corticosteroids
for both prevention and treatment of AR
it showed an essentially complete recovery of their renal function.
* High dose pulse therapy with intravenous methylprednisolone is associated with fewer side effects than oral prednisone therapy, become the first line therapy for AR in most medical centers.
# Polyclonal and monoclonal antibodies
* Anti-thymocyte globulin (ATG)
serum derived polyclonal antibodies obtained from horses or rabbits immunized with human lymphocytes
* Causes depletion of circulating T cells and other leukocytes through various mechanisms, including antibody- and complement dependent lysis and the induction of apoptosis, is an effective
treatment of AR with high graft survival rates
* ATG is mainly used for the treatment of steroid resistant AR and recurrent AR.
* S/E leukopenia, cytokine release syndrome, and viral infections.
# The murinederived Muromonab-CD3 (OKT3) is a monoclonal antibody based treatment directed against the CD3 molecule, which is closely associated
with the T cell receptor (TCR)
* used in treatment of AR & steroid resistant AR.
* S/E lower efficacy higher incidence of side effects compared to ATG treatment, has been withdrawn from the market.
# Immunoregulatory effects of corticosteroids:
* The therapeutic effects for the treatment of AR are due to their anti inflammatory and immunosuppressive effects, through direct and indirect regulation of immune related gene transcription (genes for cytokines, chemokines, adhesion molecules, and in-
flammatory enzymes).
* GCs increase the expression of anti inflammatory cytokines and transcription mediators.
* Prevention of leukocyte migration, induction of cell death in lymphocytes, and effects on the growth and lineage commitment of T cells.
# Steroid resistance
* Poor or no response to steroid therapy for AR reversal also occurs in recipients of other solid organ transplants, including liver, lung and cardiac allografts
* In such cases of steroid resistance, the patient requires more rigorous immunotherapy to reverse the AR episode.
* Recipients with steroid refractory rejection are generally treated with ATG, which results in a salvage rate of 70 to 90% of the cases.
# Diagnosis of steroid resistance AR
* Depend on post transplantation follow up of clinical parameters reflecting renal allograft function.
* patient’s serum creatinine levels do not return to within 120% of the pre rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy .
* ATG treatment is generally required in the first few days after the start of the steroid treatment are crucial.
* The minimal time for assessment of the response to steroids is five days after initiation of the pulse therapy.
# Assessment of risk for steroid resistance:
* The progression of irreversible nephron loss during the steroid resistance AR could be avoided, this need for tools to assess the response to AR treatment in an early stage.
* Clinical and pathologic indicators of steroid resistant acute rejection
– Acute vascular rejection is related
to resistance to high dose steroid therapy. – Presence of mononuclear cells at endothelial cells of large and small vessels in the graft.
– Presence of an immune response directed against the microvasculature. ( Patients with moderate to severe microvascular destruction respond less adequately to steroid therapy compared to patients with only mild destruction of
the microvascular endothelium.) -Extensive leukocyte infiltration into the
peritubular capillaries.
– HLA molecules can also be targeted by DSA leading to local complement activation and humoral rejection.
– Formation C4d and deposition in PTC.
# Prognostic biomarkers for steroid resistant rejection:
* Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness could provide complementary parameters for assessing the risk of adverse graft outcome.
** Immune biomarkers
– Cytotoxic T lymphocytes and NK cells
*The first immune component linked with resistance to anti rejection treatment presence of T lymphocytes.
* The extent of CD8+ T cells infiltration within the allograft was correlated with response to AR treatment with GCs
– B lymphocytes
* Increased intragraft levels of the B cell marker CD20 and B-lymphocyte associated immunoglobulins.
– Immunostainings for CD68 revealed the presence of intraglomerular and interstitial macrophagesduring AR as prognostic markers for steroid resistance and graft outcome .
** Non-immunological biomarkers
– Novel finding relation between zinc regulation and resistance to anti rejection treatment with steroids.
– High intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during AR is associated with steroid resistance.
** Combination of immune and non immune biomarkers
– No single biomarker has been able to predict the response to steroid treatment with both high sensitivity and high specificity, so combination of both immune and non immune biomarkers give better results.
# Glucocorticoid receptor expression
* Differences in response to treatment with GCs may be explained by variations in GR expression.
* Decreased GR expression has been implicated as a cause of steroid
resistance.
* The observed differences in GR expression between responders and nonresponders might be a reflection of varying levels of GR autoregulation.
* The ratio of primary GRα and cytokine induced GRβ isoforms impact responsiveness.
* Therole of GRβ in steroid resistance remains controversial.
* In addition to GR expression levels, differences in treatment response may also be explained by genetic variability.
* Study revealed no correlation between steroidrefractory AR and the GR. Both the NR3C1 genotype distribution and
GR expression levels in the renal allograft were similar between kidney transplant recipients with response and resistance to GC treatment of AR.
# Clinical implications
– This study guide the therapeutic approaches for treatment of steroid
refractory AR episodes.
– Zinc regulation may play a role in the response to steroid therapy during AR.
– Kidney transplant recipients who express high intragraft levels of MT and
TIMP1 during AR might benefit from extra zinc intake for optimal GCsignaling.
– The presence of multiple mechanisms underlying steroid resistance probably accounts for the restricted predictive power of single markers.
– Multivariate prediction model, containing biomarkers related to different aspects of GC signaling, offers a superior
– Such a multivariate approach could identify patients with insufficient response to anti rejection treatment with GCs, who would benefit from immediate ATG treatment.
# How would this study change your practice?
– Early diagnosis of steroid resistant acute rejection is important to prevent further graft damage.
– AR need further study and methods to predicted than ordinary one that used in our practice.
– Not all AR responding to GC.
Renal biopsy and C4d should taken as soon as possible to looking for causes of rejection
– So we can start with steroid for short period if there is no response we shift to ATG , when biopsy confirm the ABMR plasma exchange and IVIG.
– Recipients with acute rejection may benefit from extra zinc intake which may have a role in response to steroid therapy
Reem Younis
3 years ago
.-Acute rejection (AR) associates with the development of chronic allograft Failure and loss of a transplanted kidney. Several therapeutic options are available for the reversal of AR episodes: Synthetic corticosteroids
-Intravenous pulse therapy with high-dose methylprednisolone is the first-line therapy for AR in most medical centers. Polyclonal and monoclonal antibodies
-ATG is used for the treatment of steroid-resistant AR and recurrent AR. Immunoregulatory effects of corticosteroids(GC):
-The therapeutic effects of synthetic GCs for the treatment of acute
renal allograft rejection is attributed to their anti-inflammatory and
immunosuppressive effects.
-The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes, and increasing the expression of anti-inflammatory cytokines and transcription mediators. Steroid resistance
-25 to 30% of the patients with AR episodes cannot be reversed with corticosteroid therapy alone.
-Renal allograft recipients with steroid-refractory rejection are generally treated with ATG, which results in a salvage rate of 70 to 90%.
– An AR episode is considered steroid-resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy.
-Incomplete restoration of graft function in steroid-resistant rejection may lead to progression of chronic damage to the graft and has a detrimental effect on graft outcome. Assessment of risk for steroid resistance Clinical and pathologic indicators of steroid-resistant rejection
-Acute vascular rejection is related to resistance to high-dose steroid therapy and a subsequent higher chance of graft failure.
-Steroid resistance therapy has been associated with the presence of mononuclear cells in endothelial cells of large and small vessels in the graft.
-Steroid-refractory AR has been associated with more extensive leukocyte infiltration into the peritubular capillaries.
-C4d deposition in PTC has been associated with steroid resistance. Prognostic biomarkers for steroid-resistant rejection
-Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness could provide complementary parameters for assessing the risk of adverse graft outcomes.
-Resistance to GCs has been associated with increased expression of cytotoxic
T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage
signatures.
-Patients with steroid-refractory AR expressed increased intragraft levels of the B cell marker CD20 and B-lymphocyte-associated immunoglobulins.
– Immunostainings for CD68 revealed the presence of intraglomerular and interstitial macrophages during AR as prognostic markers for steroid resistance and graft outcome. Non-immunological biomarkers
-There is a link between zinc regulation and resistance to anti-rejection treatment with steroids.
-High intragraft expression of metallothioneins (MT) and tissue inhibitor of
metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with steroid resistance.
-differences in response to treatment with GCs may be explained
by variations in GC-receptors expression.
Hinda Hassan
3 years ago
Steroid role in treatment of graft rejection is modulated through the following mechanisms
· suppression of inflammatory genes
· increasing the expression of anti-inflammatory cytokines and transcription mediators
· prevention of leukocyte migration,
· induction of lymphocytes death
· effects on the growth and lineage commitment of T cells
Steroid resistance is due to immunological and non-immunological factors. Steroid resistence rejection is defined as failure of returning . this article defined Steroid resistance as failure of serum creatinine to “return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy”
Clinical and pathologic indicators of steroid resistant rejection
· Acute vascular rejection
· presence of mononuclear cells at endothelial cells of large and small vessels in the graft
· moderate to severe microvasculature destruction · extensive leukocyte infiltration into the (PTC) which target HLA molecules · C4d deposition in PTC Prognostic biomarkers for steroid resistant rejection are difficult to be identified due to differences in definitions of SR,patients cohort and analysis techniques . Combination of both immune and non immune biomarkers shows some promising results. a) Immune biomarkers 1- High expression of cytotoxic T lymphocyte & natural killer (NK) cell (relatively high biopsy FasLmRNA expression and dense granulysin staining beside lowurine FoxP3 ). T cell activation markers CD25:CD3ε ratio and lymphocyte activation gene-3 (LAG-3) 2- high B lymphocyte , B cellmarker CD20 and B-lymphocyte associated immunoglobulins 3- intra graft macrophage(CD68) and are associated with intimal arteritis and C4d deposition b) Non-immunological biomarkers through zinc regulation : Relatively high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) in activated macrophages and tubular epithelial decrease cellular zinc ions needed for steroid signaling
this study will encourage us to persuade our local lab to adopt the use of the new biomarkers beside the histological findings in graft biosies.
Ban Mezher
3 years ago
Renal transplantation is the best option for patients with ESRD. From the beginning of transplantation there was a large obstacle( Acute rejection). After using if IS the incidence of AR reduced dramatically ( 80% – <15%) with improvement of 1 year survival to >90%. Inspire of these improvement in treatment graft survival, AR still the main cause of graft failure.
Treatment of AR:
Synthetic CS: since 1960 the using of GC in treatment of AR show a large benefit. Both high dose oral GC or IV Pulse steroid had same efficacy in AR treatment but with very high incidence of side effects among patients receive oral treatment.
polyclonal & monoclonal antibodies: ATG can deplete circulating T cells through Ab- mediated cell lysis, complement dependent lysis, & inducing cell apoptosis. It is very effective in AR treatment but had serious side effects as leucopnea & cytokine release syndrome, so it used for steroid resistant Amor recurrent rejection. OKT3 is a monoclonal Ab also used for AR treatment but due to serious side effects & lower efficacy than ATG it not used any more.
GC act through suppression of inflammatory genes which activated during AR ( genes encode for cytokines, chemokine, adhesion molecules & inflammatory enzyme genes), in addition to prevention of WBC migration, inducing cell death of lymphocytes. GC action mediated through intracellular GC receptor (GR).
Large number of AR episodes can be treated with high dose of GC but 25%-30% of patients not respond to CS alone. Steroid resistant AR defined as failure of creatinine to return to 120% of pre transplant base line after 14 days of steroid treatment.
Predictors of CS restraint AR: (a) clinical & pathological :
acute vascular rejection
presence mononuclear cell in large & small vessels
immune response against microvasculature
extensive WBC infiltration of PTC
C4d deposition in PTC
(b) immune biomarkers:
CD8 T cells infiltration
B cells infiltration
macrophages infiltration
(c) non immune biomarkers:
zinc regulation
high expression of TM T TIMP-1.
using of both immune & non immune markers to improve sensitivity & specificity of risk assessment of steroid resistant AR.
Wael Jebur
3 years ago
Road o HLA antibody evaluation: MFI
As the technique for detection of HLA antibodies has developed tremendously over the years from CDC assay to flow cytometry with implementation of cytometric cross match that involved the simultanous and independent assessment of both T and B cell crossmatches, to the ultimate microparticle technology. This development significantly improved the sensitivity for detection and characterization of various types of HLA antibodies.Nevertheless,this sensitive technique was not flawless, and the detected antibodies were desputably interpreted in relation to allograft outcome.
This article tried to address the different aspect of the technique and the significance of the detected antibodies with recommendation and roadmap to follow.
The microparticle technology became the surrogate lymphocytes targets,as it’s coated with class I and Il molecules. SAB assay is semiquantitative test used to assess antibody specificity.
The major contention related to SAB revolved around results reported as a numerical value referred to as mean flourescent intensity MFI.
Concerns about MFI:
1) It never intended to quantify HLA antibodies.,nor was Luminex approved as a quantitative assay.
2) MFI values reflect a given bead relative fluorescence without reference to a standered.,nevertheless, MFI was consistently used as semiquantitative assessment of antibody strength.
3)Limitations of use of MFI:
a)Threshold for positive or negative MFI ,too low false positive may preclude the patients,or too high would increase the risk of having AMR.
b) controversially, some patients transplanted against extremely low DSAs titer (100 MFI).experienced poor graft survival, in contrast, patients with (10000 MFI) had negative cross match and excellent graft outcome.
c)SAB assay is sensitive to technologist dependent action.
d)MFI value might be affected by antibody dependent complement activation,Complement split products covalent bind toantigen_antibody complexes on the beads and block binding sites for secondary reporter antibodies.
e)The presence of IgM HLA antibodies will compete and prevent the binding of IgG HLA antibodies, resultant in misleading lower MFI value associated with adverse allograft prognosis.
f)false positive MFI can occur from binding of antibodies to misfolded HLA protein, called denatured antigens,where reactivity is attributed to antibody binding of cryptic epitop,which is under normal condition ,considered as antibody unaccessible.This phenomena might be explaining why some patients with high MFI DSAs were not associated with poor graft outcome.
G) Significance of antibodies against denatured HLA antigens are yet to be addressed.
CREGs ,Epitops and Eplets:
A serologic phenomina of multiple unique HLA antigens that reacted with a single antibody
Conformation,an integral component to antibody pathogenicity:
Specific eplets or even a single amino acid difference in the epitops of different HAL antigens can change the reactivity of the HAL antigen and the potential HLA DSAs response.
HLA antigen and DSAs pathgenesity;
It’s crucial to notice that microparticles In SAB assay are coated with an amount of antigen designed to detect low level of antibodies,not to mimic the quantity of HLA antigens on lymphocytes or tissues.Therefor Invitro DSAs binding may not be the same invivo due to different concentration of HLA antigen.
Nevertheless HLA antigen is increasing with inflammation and HLA antigen may be susceptible to DSAs. Therefore it was reported that the most common de novo DSAs post transplant are those against HLA_DQ antigen,,despite low expression of DQ loci.
In vitro DSAs with low MFI could be due to low concentration of the DSAs,that spread over many HLA antigens sharing public epitops ,non of them are adequate to produce flourescent signal detected,in comparison these DSAs can combine in vivo to HLA antigen could be a target to same antibodies..
Importantly, DSAs pathogenecity can’t be assessed by MFI level.
Assessing Pathogenesity of DSAs:
Complement fixing is an important tool to assess the pathogenecity of DSAs,C1q assay is the most common tests,IgG 1 and IgG 3 both are Complement fixing and can be the culprit for AMR.however it’s debatable,as in vitro Complement fixing might not be happening in vivo as well.
Furthermore ,non complement fixing AMR, but Antibody dependent cellular cytotoxicity through Natural killer cells.
In conclusion ,each patient is different, and multidisciplinary team to assess histocompatibity for each patient.
Abdul Rahim Khan
3 years ago
The acute renal graft rejection is one of the main causes of graft loss and outcome. In 1960s , about 40 percent patients who had kidney transplant would survive by end of first year post transplantation. with newer immunosuppressive drugs and regimens the graft survival has increased and the chances of acute rejection have decreased . Currently it is around 15%. Banff classification is used to identify severity of rejection on the basis of site and degree of inflammation.
Treatment of acute renal allograft rejection.
Synthetic Corticosteroids
Initially oral prednisolone was used which had significant side effects like GI side effects. Later it was changed to IV methyprednisolone . Now a days the pulse therapy with IV methyprednisolone has become first line treatment of acute rejection in most centres.
Polyclonal antibodies
ATG is very effective treatment of Acute rejection and improves graft survival , However there can be complications like infections , leukopenia and cytokines storm. It can be used for recurrent or steroid resistant Acute rejection. OKT3 is mono clonal antibody directed against T cells receptor and depletes circulating T cells. I t can be used in primary and steroid resistant AR. due to less efficacy and more side effects it has been withdrawn from market.
Mechanism of action of steroids
Increase the transcription of transcription mediators and anti inflammatory cytokines and also regulate genes expressed in leukocytes. They have anti inflammatory effects and suppress genes activate during AR including inflammatory enzymes, chemokines and adhesion molecules
Steroid resistance
About 20-30 percent patients will show steroid resistance and it can be diagnosed by following the clinical parameters. AR episode is labelled as steroid resistant when serum creatinine level do not return to 120% of baseline pre rejection levels after pulse therapy with steroids. Histology in these cases shows extensive leukocyte infiltrate in peritubular capillaries.c4d deposition is also associate with steroid resistance.
Steroid resistant rejection is treated with ATG usually.
How would this change my practice.
Acute rejection is significant entity and is usually multifactorial . Renal biopsy should be considered early to diagnose and assess severity of rejection. If these is no response to steroids then ATG must be given . DSA should be monitored . For AMR IVIG and plasamphresis must be given. Drug metabolism and zinc regulation have a role in response to steroid therapy.
Weam Elnazer
3 years ago
Summary;
In the case of acute rejection, which is most common in the early post-transplant period, it is linked with poor graft prognosis, manifested as chronic graft malfunction and graft loss, among other manifestations. Only 25-30 per cent of rejects responds well to glucocorticoid therapy alone and hence become steroid-resistant. This is linked with an increased risk of graft failure in the long term. ATG is used to treat acute rejection that is resistant to steroid therapy and that has recurred.
When the serum creatinine does not reduce to less than 120 per cent of the baseline level after 14 days of receiving pulse steroid treatment, it is termed to be resistant to steroids (steroids resistant rejection). The standard time span for evaluating steroid response is 5 days following the start of pulse steroid therapy. Usually, ATG therapy is essential at this point in time (which has a 70-90 per cent success rate in reversing rejection). Zinc supplementation is beneficial in the regulation of glucocorticoid signalling.
Perspectives for the future
It is necessary to conduct validation and verification studies on the prognostic significance of suggested biomarkers.
Before these models may be used in clinical practice, prospective investigations are required.
The expression of microRNA transcripts is a biomarker that is still in its infancy.
MicroRNA expression patterns in graft biopsies may be used to identify new predictive biomarkers for the fate of AR, according to the researchers.
The identification of non-invasive molecular markers in blood and urine may allow for the early diagnosis of graft malfunction and the prompt implementation of corrective measures.
The response to high-dose GC for AR therapy is correlated with the expression level and features of T cells and macrophages penetrating into the allograft, according to the findings.
This indicates that steroid resistance is restricted to certain cell types and is not a characteristic of all lymphocytes, as previously thought.
AR is characterized by altered zinc regulation and drug metabolism that influence steroid response.
Increased zinc consumption may help to improve GC signalling and assist transplant patients, according to research.
The use of a multivariate prediction model in clinical practice may aid in the more accurate evaluation of steroid resistance as well as the individualization of anti-rejection treatment.
What changes do you think this research will bring to your practice?
If there is no ideal response to steroids after 5 days, ATG should be investigated.
Treatment as soon as possible will stop the progression of the disease.
MOHAMMED GAFAR medi913911@gmail.com
3 years ago
an episode of acute rejection is a period of uncertainty and is like to cause anxiety in ktrs and thier carers.
the occurrence of acute rejection (AR) is a dominant risk factor for adverse graft outcome. in the 1960s, AR was the most important cause of kidney transplant loss. Only 40% of renal allograft recipients had a functioning graft at one year after transplantation .The introduction of immunosuppressive medications and refinement in treatment regimens during the following decades has reduced the incidence of AR from over 80% in the 1960s to below 15% nowadays .
Tretamnt of renal allograft rejection
A-synthettic corticostreoids,
Treatment of AR with high doses of oral prednisone was found to po- tentially induce toxic side effects, such as gastrointestinal hemorrhage and increased susceptibility to infection. To prevent these complica- tions, the treatment was switched from oral prednisone to intravenous application of methylprednisolone during the early 1970s .
How steroid works?
1- regulate approximately 20% of all genes expressed in leukocytes .
2 -suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and in- flammatory enzymes .
3-increase the expression of anti- inflammatory cytokines and transcription mediators .
why some AR episodes dosent repond to steroids, or partially repons (steroid resitstant)?
1-25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone.
2- An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy .
3- Several parameters have been associated with response to steroid treatment.
4-Acute vascular rejection is related to resistance to high-dose steroid therapy and a subsequent higher chance of graft failure .
5-Steroid-refractory AR has been associated with more extensive leukocyte infiltration into the peritubular capillaries (PTC) .
6-C4d deposition in PTC has been associated with steroid resistance .
7-The extent of CD8+ T cells infiltration within the allograft was correlated with response to AR treatment with GCs .
8-Patients with steroid-refractory AR expressed in- creased intragraft levels of the B cell marker CD20 and B-lymphocyte as- sociated immunoglobulins .
9-Macrophage infiltration within the kidney transplant has been related with response to GC therapy .
10-Relatively high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is as- sociated with steroid resistance .
B-polyclonal and monolclonal antibodies,
ATG is an effective treatment of AR with high graft survival rates . However, ATG can induce complications, such as leukopenia, cytokine release syndrome, and viral infections . Due to the risk of complications,
ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR.
How would this study change your practice?
AR is a complex episode , and it depends on a lot of factors , wether this transplant is aliving one or cadveric. how many mismatches between the donor and the recipent .is the recipent is highyly sensitized or not .is there DSA befor transplantion or not .how far is the recipent from transplantion.
all these data should be kept in mind during rejection episode .
steroids are the corner stone of treatment of AR episodes, and judment of response can be made by the phyiscain himself keeping in mind the data mentioned befor about the recpient and the donor .and descion of switching the patient to more aggresive tetament depends mainly on histopathological findings regarding BANF classification.
Last edited 3 years ago by MOHAMMED GAFAR medi913911@gmail.com
Shereen Yousef
3 years ago
*Introduction
improving long-term graft survival is the main goal of all doctors Since 40% of renal allografts fail within the first 10 years and there is shortage of donors togerher with difficulties in second transplant.
*Impact of acute rejection:
AR is a major risk factor for adverse graft outcome,
It usually occurs in the early post-transplant period, commonly in first 3months.
With advances in immunosuppssion AR remains the primary cause of renal allograft failure. Approximately 10% of all graft losses are directly caused by acute renal allograft rejection.
Early detection of AR episodes is important for the prevention of adverse graft outcome.
Diagnosis is made clinically and by histopathologic changes of kidney biopsy.
It may present just with rise in serum creatinine.
The Banff classification can detect severity of rejection episodes.
clinical and histopathologic assessment cant predict the response to ttt accurately. And we need biomarkers to provide complementary parameters for assessing the risk of adverse graft outcome.
AR episods is associated not only with a significant reduction in long-term allograft survival but also with graft loss, and chronic allograft failure. Renal interstitial fibrosis and tubular atrophy (IFTA)—which was formerly known as chronic allograft nephropathy (CAN)—is the most prevalent cause of chronic allograft failure after the first post-transplant year.
*Treatment of acute renal allograft rejection
All recipients are treated with immunosuppressive drugs to minimize the chance of AR, which act by inhibiting the activation and/or effector functions of T cells.
But acute rejection can still happen despite proper HLA matching and induction therapy and maintenance immunosuppression.
-therapeutic options for reversal of AR episodes;
1-Synthetic corticosteroids;In 1963, Starzl and his colleagues found that AR can be reversed by high doses of prednisone ,
And now intravenous pulse therapy with high-dose methylprednisolone has become the first-line therapy for AR in most medical centers.
2- Polyclonal and monoclonal antibodies;
ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR.
*Immunoregulatory effects of corticosteroids;
GCs regulate approximately 20% of all genes expressed in leukocytes
major action of GCs is the suppression of inflammatory genes that become activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and in-flammatory enzymes .
GCs also increase the expression of anti-inflammatory cytokines and transcription mediators they also suppress AR through a variety of other mechanisms, including the prevention of leukocyte migration, induction of cell death in lymphocytes, and effects on the growth and lineage commitment of T cells.
GCs actions are mediated by the intracellular glucocorticoid receptor (GR), GC-GR complex interferes with activating transcription factors, such as nuclear factor-κB (NF-κB), activator protein-1 (AP-1), and cyclic AMP-responsive element-binding (CREB), the GC-GR increases the transcription of inhibitor of κB(IκB) and MAP kinase phosphatase (MKP)-1, which inhibit NF-κB and mitogen-activated protein (MAP) kinase, respectively .
AR episode is considered steroid resistant serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after steroid therapy .
ATG treatment is generally required in steroid resistant cases with re assessment of the response to steroids in five days after initiation of the pulse therapy.
Predictors of steroid resistance
-Acute vascular rejection is related to resistance to high-dose steroid therapy.
-presence of mononuclear cells at endothelial cells of large and small vessels in the graft .
-presence of an immune response directed against the microvasculature.
-extensive leukocyte infiltration in PTC.
-C4d deposition in PTC ,although this association could not be confirmed in a recent study .
*Prognostic biomarkers for steroid resistant rejection
Immune biomarkers;
Resistance to GCs has been associated with increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage signatures.
Non-molecular biomarkers and zinc metabolism may predict rejection resistance to glucocorticoid use.Relatively high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with steroid resistance.
Decreased GR expression has been implicated as a cause of steroid resistance in a wide variety of diseases, including nephrotic syndrom.
steroid resistance is a complex and multifactorial condition,both T cells and macrophages play an important role in the response to steroid therapy
recipients with high intragraft levels of MT and TIMP1 during AR might benefit from extra zinc intake for optimal GC signaling.
*How would this study change your practice?
Renal biopsy as early as possible to detect histological features and severity of the rejection.
ATG to be considered after 5 days if no optimal response to steroids
Zinc supplements to patients during acute rejection.
DSA should be checked in rejection and PE AND IVIG FOR AMR
Impact of acute rejection on the graft
AR continues to be a primary cause of renal allograft failure.10% of all graft losses are directly caused by acute renal allograft rejection. In addition, the occurrence of AR correlates with a significant reduction in long-term allograft survival. Beside this association with risk of graft loss, AR is also correlated with the development of chronic allograft failure. Renal interstitial fibrosis and tubular atrophy (IFTA)—which was formerly known as chronic allograft nephropathy (CAN)—is the most prevalent cause of chronic allograft failure after the first post-transplant year.
Treatment of acute renal allograft rejection
– Corticosteroids: Nowadays, intravenous pulse therapy with high-dose methylprednisolone has become the first-line therapy for AR in most medical centers.
– Polyclonal and monoclonal antibodies
ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR
The murine derived Muromonab-CD3 (OKT3) is a monoclonal antibody, but due to its lower efficacy and higher incidence of side effects compared to ATG treatment, OKT3 has been withdrawn from the market and is no longer in clinical use.
Immunoregulatory effects of corticosteroids
The therapeutic effects of synthetic GCs for the treatment of acute renal allograft rejection are attributed to their anti-inflammatory and immunosuppressive effects.
The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes.
Besides the downregulation of pro-inflammatory genes, GCs increase the expression of antiinflammatory cytokines and transcription mediators.
In addition, glucocorticoid (GC) therapy can suppress AR through a variety of other mechanisms, including the prevention of leukocyte migration, induction of cell death in lymphocytes, and effects on the growth and lineage commitment of T cells.
Steroid resistance
25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone. Similarly, poor or no response to steroid therapy for AR reversal also occurs in recipients of other solid organ transplants, including liver, lung and cardiac allografts. In such cases of steroid resistance, the patient requires more rigorous immunotherapy to reverse the AR episode.
Renal allograft recipients with steroid-refractory rejection are generally treated with ATG, which results in a salvage rate of 70 to 90%.
Diagnosis of steroid resistance primarily relies on post-transplantation follow-up of clinical parameters reflecting renal allograft function. An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy. At that point, ATG treatment is generally required.
The first few days after the start of the steroid treatment are crucial. Analysis of creatinine
courses of steroid-resistant and steroid-responsive cases revealed that the minimal time period for assessment of the response to steroids is five days after initiation of the pulse therapy. Changes in serum creatinine levels were similar between patients with steroid responsive and steroid resistant AR until day 5, at which time the responders showed a significant decrease in serum creatinine, while the creatinine level of non-responders remained high. This 5-day period is also the average time delay used by clinicians before considering a rejection as being steroid resistant. Incomplete restoration of graft function in steroid resistant rejection may lead to progression of chronic damage to the graft and has a detrimental effect on graft outcome.
Assessment of risk for steroid resistance
– Clinical and pathologic indicators of steroid resistant rejection
Acute vascular rejection is related to resistance to high-dose steroid therapy and a subsequent higher chance of graft failure.
Steroid-refractory AR has been associated with more extensive leukocyte infiltration into the peritubular capillaries (PTC).C4d deposition in PTC has been associated
with steroid resistance, although this association could not be confirmed in a recent study.
– Prognostic biomarkers for steroid resistant rejection
o Immune biomarkers
Resistance to GCs has been associated with increased expression of cytotoxic
T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage signatures. However, there are some challenges regarding detection of those biomarkers and significance in clinical practice.
o Non-immunological biomarkers
A relatively novel finding is the link between zinc regulation and resistance to anti-rejection treatment with steroids. Relatively high
intragraft expression of metallothioneins (MT) and tissue inhibitor of
metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with steroid resistance.
Coagulation factor II receptor (F2R) is a regulator of numerous intracellular signaling pathways, which include NF-κB and MAP kinase pathways
Even though the biomarkers described in the previous sections provide a strong prognostic value for predicting a patient’s response to GC therapy, no single biomarker has been able to predict the response to steroid treatment with both high sensitivity and high specificity
Clinical implications
The data discussed in this review demonstrate that steroid resistance is a complex and multifactorial condition, in which both immunological and non-immunological factors can be involved. Investigations of immune-related biomarkers revealed that both T cells and macrophages play an important role in the response to steroid therapy. Combined, these findings indicate that steroid resistance resides in specific cell populations. This may guide the therapeutic approaches for treatment of steroid-refractory AR episodes. Furthermore, Zinc regulation
may play a role in the response to steroid therapy during AR. Kidney transplant recipients who express high intra graft levels of MT and TIMP1 during AR might benefit from extra zinc intake for optimal GC signaling.
this affect my clinical practise to predict steroid resistance early at day 5 of starting IV methylprednisolone so we can arrange early for the next step to preserve the grafat function
Tahani Ashmaig
3 years ago
☆Mechanisms and risk assessment of steroidresistance in acute kidneytransplant rejection:
____________
▪︎The present review provides an overview of biomarkers for the detection and/or prediction of steroid resistance in kidney transplantation.
▪︎The availability of biomarkers could provide complementary parameters for assessing the risk of adverse graft outcome.
*Introduction:
▪︎Acute rejection (AR) is primarily a cellular immune response directed against mismatched donor antigens present on the cells of the allograft, which generally occurs during the early post-transplant period, with the highest risk in the first 3 months.
*Impact of acute rejection on graft outcome:
____________
▪︎ Even after the introduction of immunosuppressive medication, AR continues to be a primary cause of renal allograft failure.
▪︎ AR is one of the risk factors for the development of renal interstitial fibrosis and tubular atrophy (IFTA) which is the most prevalent cause of chronic allograft failure after the first post-transplant year.
▪︎ Various parameters of AR determine the level of risk for adverse graft outcome including the timing, recurrence, severity, and therapy sensitivity of the AR episode.
Treatment of acute renal allograft rejection:
_______________________________________________Nowadays, almost all transplant recipients are treated with immunosuppressive drugs to minimize the chance of AR, which act by inhibiting the activation and/or effector functions of T cells.
▪︎Several therapeutic options are available for the reversal of AR episodes:
1) Synthetic corticosteroids:
Intravenous pulse therapy with high-dose methylprednisolone
2) Polyclonal and monoclonal antibodies: Anti-thymocyte globulin (ATG):
– ATG can induce leukopenia, cytokine release syndrome, and viral infections. So, is mainly used for the treatment of steroid-resistant AR and recurrent AR.
3) Murine derived Muromonab-CD3 (OKT3): due to its lower efficacy and higher incidence of side effects compared to ATG treatment, OKT3 has been withdrawn from the market and is no longer in clinical use.
* Immunoregulatory effects of corticosteroids:
_________ _________
The therapeutic effects of synthetic GCs for the treatment of acute renal allograft rejection are attributed to their anti-inflammatory and immunosuppressive effects (obtained through direct and indirect regulation of immune-related gene transcription).
The major action of Glucocorticoids(GCs):
____________________________________________
1. Suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes.
2. Down regulation of pro-inflammatory genes, GCs increase the expression of anti-inflammatory cytokines and transcription mediators.
3. Prevention of leukocyte migration.
4. Induction of cell death in lymphocytes.
5. Effects on the growth and lineage commitment of T cells
▪︎The actions of GCs are mediated by the intracellular glucocorticoid receptor (GR). After administration, GCs diffuse across the cell membrane and bind to the cytoplasmic GR and form GC-GR complex which regulates gene transcription through
direct and indirect signaling pathways.
▪︎The signaling pathways of the GC-GR complex inhibit the transcription of pro-inflammatory molecules, including cytokines, chemokines, adhesion molecules, inflammatory enzymes, and receptors.
▪︎Alterations in the molecular mechanisms of GR signaling may lead to steroid resistance.
☆Diagnosis of steroid resistance:
_________________________________
Primarily relies on posttransplantation follow-up of clinical parameters reflecting renal allograft function.
▪︎An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy. ATG treatment is generally required.
▪︎Analysis of creatinine courses of steroid-resistant and steroid-responsive cases revealed that the minimal time period for assessment of the response to steroids is five days after initiation of the pulse therapy ( An average time delay used by clinicians before considering a rejection as being steroid resistant).
Assessment of risk for steroid resistance:
____________________________________________
A) Clinical and pathologic indicators of steroid resistant rejection
▪︎At present, clinical parameters and histopathologic assessment of kidney biopsies remain the golden standard for evaluating short- and long-term graft outcome.
▪︎Unresponsiveness to steroid therapy has been associated with:
1. Presence of mononuclear cells at endothelial cells of large and small vessels in the graft
2. Presence of an immune response directed against the microvasculature.
3. Patients with moderate to severe microvascular destruction.
4. Extensive leukocyte infiltration into the peritubular capillaries (PTC)( in refractory response to steroid).
5. Circulating leukocytes target HLA molecules expressed on the PTC
6. Donor-specific antibodies
7. C4d deposition in PTC.
B)Prognostic biomarkers for steroid resistant rejection
1. Immune biomarkers: Resistance to GCs has been associated with increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage within the renal allograft.
2. Challenges for biomarker identification in clinical context: Steroid resistance may reside in activation of T cell populations as the prime candidate. However, the prognostic value of immune biomarkers is hampered by molecular heterogeneity among kidney biopsy samples with AR. This observation may be a reflection of the complexity of the mechanisms involved in response to steroid therapy.
3. Non-immunological biomarkers: Removal of zinc ions (which are normally used in GC signaling) and Coagulation factor II receptor (F2R) (Differences in F2R may influence the pro- and antiinflammatory effects of GCs)
4. Combination of immune- and non-immune biomarkers
5. Decreased Glucocorticoid receptor expression.
* Important points to consider in our practice:
___________
▪︎ Resistance to steroid therapy is a complex and multifactorial condition, in which both immunological and non-immunological factors can be involved.
▪︎ The response to high-dose corticosteroid therapy for the treatment of acute renal allograft rejection correlates with the expression level and characteristics of T cells and macrophages infiltrating into the renal allograft.
▪︎Zinc regulation and drug metabolism may play a role in the response to steroid therapy during acute renal allograft rejection. Therefore, kidney transplant recipients may benefit from additional zinc intake to optimize GC signaling.
▪︎The best prognostic value for assessing steroid response is multivariate prediction model, containing biomarkers related to different aspects of GC signaling which contributes in the clinical risk assessment of steroid resistance and helps in applying more individualized antirejection therapy
Filipe prohaska Batista
3 years ago
Acute graft rejection is one of the most frequent complications in the first three months of transplantation. In renal transplant patients, a biopsy is the gold standard for diagnosis and is usually asymptomatic, but preceded by progressive worsening of renal function (increasing creatinine values). Early treatment of rejection has an impact on recent and chronic graft survival.
Classic treatment has been the use of high doses of methylprednisolone. It has fewer side effects than oral prednisone. Glucocorticoid receptors are present on most leukocytes and their binding leads to suppression of gene regulation in the cell nucleus, leading to a drop in inflammatory cytokines, chemokines, adhesion molecules, and inflammatory mediators concomitant with an increase in anti-inflammatory mediators and cytokines.
Nearly one-third of patients may experience transplant rejection and resist the use of glucocorticoids. Patients who do not recover renal function after five days of pulse methylprednisolone are suggestive of resistance to this treatment, but there is a need for early diagnosis of this condition.
Biopsy is still the gold standard for diagnosing acute rejection and can help in the diagnosis of glucocorticoid resistance:
1. Acute vascular rejection
2. Mononuclear cells in the endothelium of graft vessels
3. Moderate to severe destruction of microvascular destruction
4. HLA molecules expressed in peritubular capillaries
5. C4d deposits in peritubular capillaries
Immune biomarkers can bring early results without the need for invasive tests such as biopsy. The early presence of T lymphocytes is a marker of rejection, mainly with cytotoxic action (CD8) or natural killers (CD16, CD56).
B lymphocytes (CD19 and CD20) activated and acting as deposits of immune complexes compromising the graft. The same occurs with macrophages (CD68) and circulating monocytes (CD14) associated with intimal arteritis and C4d deposits in peritubular capillaries.
Non-molecular biomarkers and zinc metabolism may suggest graft rejection resistance to glucocorticoid use. The expression of metallothioneins (MT) and tissue inhibitor metalloproteinase-1 (TIMP1) results in the inhibition of glucocorticoid-linked anti-inflammatory activities.
Decreased glucocorticoid receptors also decrease their effectiveness and should be considered in certain pathologies.
In kidney transplantation, the use of ATG is the most suitable alternative for lymphoablation. Even with the risk of leukopenia, cytokine release syndrome, and viral infections it is a superior alternative to muronomab.
The need for early diagnosis with good accuracy and low invasiveness is extremely important for the development of molecular diagnostic methods for appropriate therapies and increased graft survival.
Drtalib Salman
3 years ago
a summary of this article
with modern immunosuppressive drug one year graft survival reach to to more than 90 percent but long term graft survival still low and more than 40 percent of transplanted patient loss or fail graft through 10 year post transplantation commonly caused by rejection .
steroid drug of great in treatment of rejection used since 1960,steroid use as oral or pulse steroid in acute treatment of rejection .according to study there is no difference between two group in form of efficacy but side effect more with oral compared to pulse steroid.
steroid consider anti inflammatory and immunosuppressive drug.
steroid resistant occur in 25 to 30 percent of patient with rejection.
Early prediction of steroid resistant of great value because:
*Tissue biopsy ,presence of vascular involvement ,peritubular capillary C4d,presence of mononuclear cell on endothelial blood vessels wall (large or small vessel).
Depend on biomarker (immunological and non immunological). Immunological:
*CD8+Lymphocyte infiltrate’s to graft corelated with steroid response .
*increase intragraft level of CD20 and B lymph immunoglobulin associated with steroid resistant .
*immunostaining for CD68 reveal presence of intra graft macrophage so indicator of steroid resistant and graft loss .
Non immunological :
novel finding related to Zink regulation through increase level of metallothionin (MT)or tissue inhibitor of metalloproteinase (TIMP).
so as to increase the sensitivity and specifity we need to use both immunological and non immunological.
How would this study change your practice?
steroid resistant should be assessed early in rejection to avoid unnecessary prolong course ,higher dose and repeat dose .
think about use of zinc with steroid to enhance response .
study should be continue to improved long term graft survival .
Wael Jebur
3 years ago
Acute rejection AR, is a risk factor for the allograft ,despite the major advances in immunosuppressive medications that has improved the first year graft survival to more than 90%. AR still reported to occur with incidence of 15 % .50 % of graft from deceased donor and 30 % of graft from living donors ,failed within 10 years. Acute rejection AR is a major risk factor for the adverse long term outcome of the renal allograft. Therefore diagnosing, treating and reversing the AR promptly is potentially improving the long term prognosis of the renal allograft.
IFTA, is the most prevalent cause of chronic allograft failure after the first year post transplantation. AR is the primary risk factor for IFTA. Although the incidence of AR has decreased significantly over the last decade, it’s negative impact on the allograft with subsequent development of IFTA has become more prominent.
Certain features of AR portend higher risk for IFTA, these include timing, recurrence,severity and therapy . Late AR (happening after 3 months post transplantation, recurrent rejections, acute vascular rejection (Banff class Ii) ,and unresponsiveness to the therapy,all linked to higher incidence of IFTA and allograft failure. AR is mainly CMR directed against mismatched donor antigen present on the cells of the allograft.
Basically treatment of acute CMR is with high dose pulse steroid ,which is working by binding to glucocorticoid receptor forming Gc_GR complex that inhibit NF_kF and prevent activation of inflammatory genes. However in 25_30 % of patients,the rejection episode is resistant to steroid therapy.
Second line therapy for steroid resistant AR is ATG which result in salvage of 70 to 90 % of cases.
Diagnosis of steroid resistant AR is dependent entirely on follow up of renal function parameters post pulse steroid therapy, steroid effect is noticed after 5 days when creatinine drops significantly. Steroid resistant is diagnosed when there is no reduction of creatinine after 5 days of starting steroid therapy. These five days are crucial for the long term adverse effect on the allograft, during which,the development and progression of nephron loss is undertreated with steroid alone . Furthermore, the patient will be exposed to the side effects of high dose corticosteroid therapy.
Henceforth, the identification of steroid resistant AR at the time of diagnosis is of prime importance to offset the two detrimental factors associated with the late diagnosis of steroid resistant AR.
Identifying the steroid resistant AR:
Acute vascular rejection
Presence of mononucleosis cells on endothelial cell surface of small and large blood vessels in the graft.
Presence of C4d in PTCs
Increased expression of cytotoxic T lymphocytes.
Natural killers
B_lymphocytes. CD20
Macrophage cells infiltration.
High intra_graft expression of metallothionien MT and tissue inhibitors of metalloproteinases.
Glucocorticoid Receptor expression level associated with steroid responsiveness.
Conclusion and take home message:
AR is an important factor linked with IFTA.
Prompt treatment will reverse the process
Identification of steroid resistant AR on time of diagnosis will reduce nephron loss,progression to IFTA and avoid unnecessarily high dose steroid.
Amit Sharma
3 years ago
III. Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection
Please give a summary of this article
Acute rejection, mostly seen in early post-transplant period, is associated with poor graft prognosis in form of chronic graft dysfunction and graft loss. 25-30% of rejection is not amenable to glucocorticoid treatment alone, hence is steroid resistant,and has been associated with higher risk of graft failure. ATG is used for treatment of steroid-resistant and recurrent acute rejection.
Steroids regulate 20% of all genes expressed in leukocytes, suppress inflammatory genes activated in rejection like genes encoding cytokines, chemokines, adhesion molecules and inflammatory enzymes. They inhibit leukocyte migration, cause induction of cell death in lymphocytes and have effect on growth and lineage commitment of T cells. Steroids act on GR (glucocorticoid receptor), activating it by removing the GR inhibitory complex and enter nucleus after dimerization, where they act on GRE (glucocorticoid response elements) and lead to increase in anti-inflammatory genes, reduction in pro-inflammatory genes, zinc dependent recruitment of HDAC-2, inhibiting active chromatin causing decrease in activation of pro-inflammatory genes as well as decreased cell proliferation during inflammatory process by inhibiting MAP kinase. So altered molecular mechanisms of GR signalling can cause steroid resistance.
Steroids resistant rejection is considered when the serum creatinine does not fall to less than 120% of the baseline within 14 days after pulse steroid therapy. The usual time period to assess steroid responsiveness is 5 days after initiation of the pulse steroid treatment. ATG treatment is usually required at this time (which has a 70-90% success rate in reversing rejection). Additional zinc intake is helpful in glucocorticoid signaling.
Steroid resistance is present in specific cell populations. Clinical and pathological parameters of steroid resistance include acute vascular rejection, mononuclear cells at endothelial cells of mall and large vessels in graft, immune response directed against vasculature, more extensive leukocyte infiltration iand C4d deposition in peritubular capillaries. Immune biomarkers of steroid resistance include increased cytotoxic T lymphocyte – NK cell signature (increased FasL mRNA, decreased FoxP3 in urine and increased dense granulation stain in biopsy), B lymphocyte signature (increased CD20 and B lymphocyte associated immunoglobulin in the graft), and intraglomerular and interstitial macrophage signature (CD68) as well as increased CD25-CD3e ratio and LAG-3 (lymphocyte activationgene-3). Non-immune biomarkers include removal of zinc ion by increased intragraft metallothioneins (MT) and TIMP-1 (tissue inhibitor of metalloproteinase-1) and F2R (coagulation factor II receptor). Decreased GR expression has been associated with reduced ratio of GRalpha/ GRbeta.
So steroid resistance has multiple factors and T cells with macrophages play important role in steroid response to the rejection.
How would this study change your practice?
A kidney biopsy with DSA should be done as early as possible in suspected rejection. in absence of response to steroids within 5 days, possibility of steroid resistance is high and hence ATG administration should be considered, if DSA negative and no evidence of AMR. Early use of second line treatment improves graft prognosis.
The changes in my practice after going through the article:
1) More vigilant to steroid resistance.
2) Early kidney biopsy
3) Zinc supplementation in acute rejection
4) Start ATG if no response after 5 days of starting steroid treatment.
5) Treat associated AMR (if biopsy evidence, DSA present) with IVIG/ plasmapheresis.
Mohamed Saad
3 years ago
Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection . Introduction:
The best modality of RRT in ESRD is Renal transplantation with improving quality of life but still acute rejection is a major challenges and one of the most common cause of poor graft outcome most of the attacks responding to anti-rejection measure especially glucocorticoid and other not responding so presence of biomarkers for steroid resistance rejection is important. . Impact of acute rejection on graft outcome:
Incidence of acute rejection correlates with the graft failure and chronic allograft dysfunction, which depends on many factors such repeated attacks of rejection , type , time and responding to treatment or not.
. Treatment of acute renal allograft rejection:
1-Synthetic corticosteroids:
Idea started with increasing dose of daily maintenance steroid to treat AR, now pulse steroid is considered the cornerstone in treatment of AR.
2-Polyclonal and monoclonal antibodies:
It’s the first line of treatment steroid resistant acute rejection. . Immuno-regulatory effects of corticosteroids:
In-brief GC led to downregulation of pro-inflammatory genes, GCs increase the expression of anti-inflammatory cytokines and transcription mediators which has a major role in rejection treatment which medicated via GR.
. Steroid resistance:
Majority of acute rejection cases in solid organ transplantation is responding to high dose GC but around 20-25 % partially respond or resistant to GC , and need other immunomodulatory drugs like ATG.
An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy.
. Assessment of risk for steroid resistance:
.1. Clinical and pathologic indicators of steroid resistant rejection:
Histological markers associated with liability of steroid resistant AR , mainly microvascular infiltration with inflammatory cells , leucocytes in PTC with C4d degradation in PTC with serological HLA DSA antibodies.
2. Prognostic biomarkers for steroid resistant rejection.
=Cytotoxic T lymphocytes and NK cells. The first immune component linked with resistance to anti-rejection treatment and graft outcome.
=Patients with steroid-refractory AR expressed increased intra-graft levels of the B cell marker CD20 and B-lymphocyte associated immunoglobulin.
=Immunostainings for CD68 revealed the presence of intra-glomerular and interstitial macrophages during AR as prognostic markers for steroid resistance and graft outcome.
=Non-immunological biomarkers.
A relatively novel finding is the link between zinc regulation and resistance to anti-rejection treatment with steroid.
=. Glucocorticoid receptor expression.
Decreased GR expression has been implicated as a cause of steroid resistance in a wide variety of diseases, including nephrotic syndrome , acute lymphoblastic leukemia [160], and asthma . The observed differences in GR expression between responders and non-responders might be a reflection of varying level of GR autoregulation which might be due to GR mutations.
. Clinical implications:
Steroid resistant AR is a multifactorial due to immunological and non-immunological causes like T cell and macrophages dominant and zinc dysregulation so we should be aware about this condition to avoid over dose of GC without benefit and also will gain side effects. Conclusion
Acute rejection especially cellular rejection mainly responding to GC some time 20-25 % GC resistant AR, mainly dependent on many factors immunological and non-immunological (for example Zinc regulation and drug metabolism may play a role in the response to steroid therapy and features of ABMR with specific histological changes in renal biopsy). How would this study change your practice?
Not all AR responding to GC.
Renal biopsy should taken as soon as possible and looking for histological features to decide regarding suitable treatment.
If not responding or stuck RFT start with ATG and if thee is features of ABMR start (IVIG+PE).
New biomarkers need more clinical evident studies.
Mohamed Mohamed
3 years ago
III. Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection
Please give a summary of this article
Introduction Acute rejection (AR) is a dominant risk factor for poor graft outcome.
AR is mostly a cellular immune response against mismatched donor antigens present on the cells of the allograft. It occurs early post-transplant, with the highest risk in the 1st 3 months.
The majority of AR episodes are reversed with steroids, however 25-30% of cases fail to respond to steroids alone.
The diagnosis of steroid resistance, so far, mainly rests on the follow up of clinical parameters that reflect the graft function. It remains difficult to predict the response to anti-rejection treatment.
If steroid resistance could be predicted, it will prevent the unnecessary exposure to high-dose steroid therapy.
The impact of steroid-resistant rejection on graft outcome necessitates the search for a mean to assess the treatment response at an early stage of AR.
This article presents the current understanding of steroid-resistance in the setting of acute rejection.
It also gives an overview of biomarkers for the detection &/or prediction of steroid resistance in AR.
Treatment of acute allograft rejection The immunosuppressive drugs used to decrease the occurrence of AR act by inhibiting the activation &/or effector functions of T cells. Despite optimum HLA compatibility & use of induction & maintenance therapy, recipients can still develop AR.
Therapeutic options used for the reversal of AR include synthetic corticosteroids & polyclonal & monoclonal antibodies.
Steroids are used for both the prevention & treatment of AR. High dose IV methylprednisolone is used in most centers as the 1st line treatment for AR.
ATG (a polyclonal antibody)is used only in steroid resistant rejections due to its risk of complications.
Corticosteroids
Anti-inflammatory & immunosuppressive effects are responsible for their therapeutic utility for the AR. They exert protective effects on the allograft via direct & indirect regulation of immune-related gene transcription. They suppress the inflammatory genes that are activated during AR, e.g. genes encoding for cytokines, chemokines, adhesion molecules, & inflammatory enzymes. They also upregulate the expression of anti-inflammatory cytokines & transcription mediators. Their other mechanisms include the prevention of leukocyte migration, induction of apoptosis in lymphocytes, & effects on the growth & lineage commitment of T cells.
The actions of GCs are mediated by the intracellular glucocorticoid receptor (GR) which have 2 isoforms, namely GRα & GRβ. The former is predominantly expressed, activated by GC binding & mediates most of the known immuno-modulatory effects.
Steroid resistance In 25 – 30% of cases the AR cannot be reversed with corticosteroid therapy alone. Such steroid-resistant patients require ATG, which results in a salvage rate of 70-90%. AR is labeled as steroid resistant if the serum creatinine levels do not drop to within 120% of the baseline after pulse therapy with corticosteroids within 14 days after the start of the steroid. The minimal time period for assessment of the response to steroids is 5 days after start of the pulse therapy. Assessment of risk for steroid resistance Prediction of steroid resistance at the time of biopsy obviate unnecessary exposure to high-dose corticosteroids And would allow early introduction of salvage ATG therapy. Clinical & pathologic indicators of steroid resistant AR Parameters include: – Acute vascular rejection – presence of mononuclear cells at endothelial cells of vessels in the graft. – presence of microvascular destruction the micro-vascular endothelium. – extensive leukocyte infiltration into the PTCs. – C4d deposition in PTC
Prognostic biomarkers for steroid resistant rejection 1.Immune biomarkers: – cytotoxic T lymphocyte & NK cells.
– B lymphocytes: increased intra-graft levels of the B cell marker CD20 & B- lymphocyte associated immunoglobulins – Macrophages: Immunostainings for CD68 revealed intra-glomerular & interstitial macrophages during steroid-resistant AR.
Challenges for biomarker identification in clinical context The interpretation & validation of the prognostic biomarkers for graft outcome are difficult as the published data have diverse definitions, endpoints & patient cohort characteristics. So later studies failed to verify the prognostic value of proposed immune biomarkers for steroid-refractory AR. To overcome these challenges, the authors assessed the intra-graft expression levels of a panel of immunological markers with steroid responsive or steroid resistant AR. The study showed that a combination of T cell activation markers CD25:CD3ε ratio & lymphocyte activation gene-3 (LAG-3) offers an improved prognostic value for assessing steroid response. Non-immunological biomarkers A novel finding is the link between zinc regulation & steroids-resistance. Increased intra-graft expression of metallothioneins (MT) & tissue inhibitor of metalloproteinase-1 (TIMP1) is associated with steroid resistance. Combination of immune- and non-immune biomarkers No single biomarker can predict the steroid responsiveness with both high sensitivity & high specificity. This is due to the fact that multiple mechanisms underly steroid resistance, as reflected by the heterogeneity in transcriptional regulation seen among AR biopsy samples. A multivariate prediction model that combines multiple biomarkers could enhance both sensitivity & specificity of steroid resistance. This model contains both immune (CD25:CD3ε ratio, LAG-3) & non-immune (MT-1, TIMP1, F2R) biomarkers as independent covariates. It offers a superior prognostic value . Glucocorticoid receptor expression Differences in response to GCs may be explained by variations in GR expression. Decreased GR expression may cause steroid resistance. The ratio of primary GRα & cytokine-induced GRβ isoforms might also impact responsiveness. However, the link between GRβ expression levels & responsiveness to GCs could not be confirmed. Genetic variability may also explain differences in treatment response. For example mutation in GR gene NR3C1 can affect the function of the GR & result in steroid resistance. However very little is known about the relationship between GR expression & the response to GCs in the transplantation field. Recent data, by the author, revealed no correlation between steroid refractory AR & the GR. NR3C1 genotype distribution & GR expression levels were similar in kidney grafts from both responders & non responders to GC. More work is needed to confirm the role of the GR in recipients with GC resistance. Clinical implications Steroid resistance resides in specific cell populations, discussed above. This may guide the treatment options of steroid-refractory AR. Zinc regulation may play a role in this context. Zinc intake might optimize GC responsiveness in recipients who express high intra-graft levels of MT & TIMP1 during AR. . The author found a multivariate prediction model cobining biomarkers related to different aspects of GC signaling. This model offers a better prognostic value compared to conventional parameters & could identify non-responders who would benefit from immediate ATG treatment. This may reduce exposure to high-dose GC, & may thus help avoid irreversible graft damage during the period that steroid-refractory AR is undertreated with steroids alone. This models may also guide the development of novel therapeutic approaches. This multivariate model that includes T cell activation markers & zinc regulating molecules as independent covariates, however does not reach 100% specificity & sensitivity for the prediction of steroid refractory AR. Future perspectives Validation & verification of the prognostic value of proposed biomarkers are required. Prospective studies are needed before adopting these models in clinical practice. The expression of microRNA transcripts is a relatively novel biomarker. Analysis of microRNA expression profiles in graft biopsies may offer novel prognostic biomarkers for the outcome of AR. Identification of non-invasive molecular markers in blood & urine may lead to earlier detection of graft dysfunction & timely intervention. Conclusion The response to high-dose GC for the AR treatment correlates with the expression level & characteristics of T cells & macrophages infiltrating into the allograft.
This is indicative that steroid resistanceresides in specific cell populations & is not a feature of all lymphocytes.
Zinc regulation & drug metabolism play a role steroid-responsiveness during AR.
The use of a multivariate prediction model in practice might help a better assessment of steroid resistance & helps in the individualization of anti-rejection therapy.
How would this study change your practice?
The study, although presented huge information regarding steroid resistance & responsiveness, however it didn’t reach to a clear, conclusive & a reproducible non-invasive marker that would obviate the need for biopsy to delineate this dilemma.
However, the study gave good insights for the future works that should concentrate on prospective clinical studies.
So, at least for the present time, I would still stick to the current conventional practice in treating steroid-refractory transplant recipients.
Mohamad Habli
3 years ago
Kidney transplantation is the best renal replacement therapy for ESRD. Despite the success of renal transplantation, approximately 40% of renal allografts fail within the first 10 years. Acute Rejection occurs in up to 10% of cases in the first year after transplantation. Diagnosis of acute rejection is based on clinical parameters and kidney biopsy results. It is difficult to predict the response to immunosuppression is based on clinical parameters and histopathologic assessment. Even after the introduction of immunosuppressive medication, AR continues to be a primary cause of renal allograft failure. the occurrence of AR correlates with a significant reduction in long-term allograft survival.
The treatment of acute rejection was historically as follows:
Synthetic corticosteroids
Early studies from 1960 demonstrated that episodes of acute rejection could be successfully managed with steroids. Side effects of steroids especially with the use of high doses were common.
In the 1970, anti-rejection treatment shifted to IV methylprednisolone instead of PO, to minimize the risk of side effects. Later studies evaluated both regimens and found them comparable in potency with fewer side effects with IV form.
Polyclonal and monoclonal antibodies
ATG therapy causes depletion of circulating T cells through mechanisms, including antibody- and complement dependent lysis and the induction of apoptosis. ATG is an effective treatment of AR with high graft survival rates. However, ATG has a lot of side effects including leukopenia, cytokine release syndrome, and viral infections.
Muromonab-CD3 is a monoclonal antibody which target CD3 molecule, which is associated with TCR. OKT3 therapy causes depletion of circulating T cells. OKT3 has been used as primary treatment of AR but associated with higher incidence of side effects compared to ATG.
The therapeutic effects of synthetic GCs are attributed to their anti-inflammatory and immunosuppressive effects. GCs regulate approximately 20% of all genes expressed in leukocytes. The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes.
Steroid resistance
in approximately 25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone. However, ATG is effective in recipients with steroid-refractory rejection with successful rate of 70 to 90% Recipients of other solid organ transplants, including liver, lung and cardiac allografts have no response to steroids in acute rejection.
Prediction of steroid resistance at the time of biopsy could prevent unnecessary exposure to high-dose corticosteroid therapy and accelerate the administration of effective alternative treatment.
Several parameters have been associated with response to steroid treatment. Acute vascular rejection is related to resistance to high-dose steroid therapy and a subsequent higher chance of graft failure.
Unresponsiveness to steroid therapy has been associated with the presence of mononuclear cells at endothelial cells of large and small vessels in the graft.
steroid resistance is the presence of an immune response directed against the microvasculature.
Steroid-refractory AR has been associated with more extensive leukocyte infiltration into the peritubular capillaries (PTC).
C4d deposition in PTC has been associated with steroid resistance.
Non-immunological biomarkers
A relatively novel finding is the link between zinc regulation and resistance to anti-rejection treatment with steroids. Most important is metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) which are responsible for zinc regulation, it was found that increase graft expression of both may be associated with steroid resistance, thus there may be a rule of zinc supplementation in patients who express high levels of MT and TIMP1 during AR.
How would this study change your practice?
In clinical practice, knowing patients with acute rejection, who are resistant to steroids, alternative immunosuppression could be initiated instead, avoiding by this mean the side effects of steroids and giving better chance for the allograft to overcome rejection.
saja Mohammed
3 years ago
Review article
aim to assess the available biomarkers of steroid resistant AR and assess its complementary effect with the clinical and histopathological tools. Introduction
————————
Acute rejection was the predominate cause of graft failure earlier in 1960 s with one-year graft survival was only 40% later on with the introduction of immunosuppressive therapy and improvement in the HLA crossmatching the graft survival improved significantly nowadays and the risk of AR reduced to < 15 % with improvement in the rate of early graft survival for more than 90, but still the 10-year graft survival reduced over time due to chronic rejection.
Acute rejection is due to the cellular immune response to the mismatched donor antigens more common in the first three months post transplantation and can be asymptomatic ,patients present with raising creatinine , and diagnosis based on clinical suspicion with the histopathological scoring of the graft biopsy diagnosis and classification based on Banff score characteristics including the assessment of the site type and degree of the inflammation in addition to the certain biomarkers that help in further assessment of AR and the likely response to treatments .
Many factors related to the AR episodes can predict the overall graft survival and outcome including the timing of AR , recurrence rate ,type of rejection and the response rate for the treatment , the late acute rejection most likely AMR can lead to chronic rejection or recurrence with progressive graft failure also acute vascular reaction with Banff class 11 associated with higher risk of graft failure in addition to the severity of AR and treatment failure also can lead to graft failure.
Treatment of acute renal allograft rejection:
Immunosuppression therapy used since 1950s for prevention and treatment of acute rejections by inhibiting the immune response mediated by the activation, effector T Cell cascades, kidney transplant recipients still at risk of acute rejections despite the optimization of the HLA crossmatching, use of induction and maintenance immunosuppression. Many therapeutic agents are availablefor the treatments of AR episodes. Synthetic corticosteroids
Corticosteroids (GCs) used for both the prevention and treatment of AR since 1963.
Steroid, preferred PMP course s for treatment of AR with lower side effect than oral steroid, and nowadays PMP used as part of induction and also in treatment of acute cellular reaction while oral steroid is part of maintenance therapy in most centers .Steroids mainly act as anti-inflammatory immunosuppression agent that led to direct and indirect inhibition of cascades of inflammatory genes that lead to reduction of proinflammatory cytokine mediators, chemokines inflammatory mediators, and increase the anti-inflammatory cytokines and mediators
Around 25-30% of AR are not responsive to GC therapy. Polyclonal and monoclonal antibodies:
1-ATG polyclonal T cell depleting agent from hoarse or rabbit act by different mechanisms as anti-body- and complement dependent lysis and the induction of apoptosis [61].
ATG is an effectives induction in high immunological risk and treatment of steroid resistant AR or recurrent ejections with favorable graft survival rates, its use limited due to higher risk of anaphylaxis, infection like CMV, BKV, and PTLD.
2-OKT3 monoclonal AB that act on CD3 pathway primarily potent T Cells depletion, previously used as induction therapy and treatment of steroid resistant rejection but due to side effects including sick sinus syndrome and serious infection was removed from the market since longtime.
Steroid resistant acute rejection:
Defined as an AR episode with failed response to pulse corticosteroids therapy within 14 days from initiation of treatment and patient’s serum creatinine levels not reduced by 120% from the pre-rejection baseline value [7,107–109]. the minimal time period for assessment of the response to steroids isfive days after initiation of the pulse therapy [96]. Failure for treatment of steroid resistant AR can lead to chronic rejection and progressive graft failure
Second line treatment by using Polyclonal antibody, ATG
Clinical and pathologic indicators of steroid resistant rejection:
presence of mononuclear cells at endothelial cells of large and small vessels in the graft [108]
·micro vascular injury Patients with moderate to severe microvascular destruction are less responsive to steroid compared to patients with only mild microvascular endarteritis [113]
more extensive leukocyte infiltration into the peritubular capillaries (PTC) (113).
Complement activation and C4 staining in the PTC indicate humoral anti HLA mediated immune response.
Prognostic biomarkers for steroid resistant rejection: Immune biomarkers considered one of an important additional tools to assess the response to treatments and prognosis of AR episodes
New molecular genetic biomarkers directing on the identification of the lymphocyte populations that are associated with poor graft outcome. Resistance to GCs has been associated with increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage signatures [99,101,120–12).
The bulk of CD8+ T cells infiltration within the allograft was linked to response of AR
treatment with GCs [123], while other molecular markers like increased mRNA expression levels of cytotoxic Tcell and NK cell (99), relatively high FasL mRNA expression [101] and dense granulysin staining (120) ,fasl RNA, low FoxP3 expression in urinary sediments [125] all correlated with refractory AR .
macrophage infiltration associated with intimal arteritis [132] and C4d deposition
in PTC [133] and steroid resistant AR.
B lymphocytes infiltration and B cells markers intraglomerular expression of CD20 and B-lymphocyte associated immunoglobulins associated with steroid resistant AR, [99,120,121].
the predictive value of immune biomarkers is hindered by molecular heterogeneity among kidney biopsy samples with AR. This observation may be a reproduction of the density of the mechanisms involved in response to steroid treatment, however the use of combination of biomarkers like (CD25:CD3ε ratio, LAG-3) and non-immune (MT-1, TIMP1,F2R) as independent covariates will offer a superior prognostic value for assessing responsiveness to GC therapy compared to both conventional clinical and histopathological indicators as well as single biomarker. This observation may be a reproduction of the density of the mechanisms involved in response to steroid treatment.
Zinc regulation may play a role in the response to steroid therapy during AR. Kidneytransplant recipients who express high intra-graft levels of MT and IMP1 during AR might benefit from extra zinc intake for optimal GC signaling, as High expression of metallothionein (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with steroid resistance [142].
Difference in glucocorticoid receptors expression ( GRβ and GRα) ,activation , GR genetic mutation will affect the response to steroid therapy in many diseases like asthma , nephrotic syndrome and lymphoblastic leukemia but in transplantation field not yet confirm its effect and need more studies
MicroRNA expression as a novel biomarker for response to steroid Therapy
Non-invasive methods for monitoring of graft outcome
Future perspective will be focusing on using noninvasive blood and urinary biomarkers for early and frequently assessing the graft dysfunction and help in timely intervention , still we need more studies for validation of the clinical use of many markers including peripheral blood mononuclear cells (PBMC) exposed to GCs which have been used to correlate gene expression profiles with clinical disorders, including steroid responsiveness [74,142,197–199].
Conclusions remarks:
Steroid resistant is complex and due to many immunological and nonimmunological factors like expression of certain types of T- lymphocytes, zinc regulating molecules effects A multivariate prediction model, containing biomarkers related to different aspects of GC signaling, offersthe best prognostic value for assessing steroid response.
How would this study change your practice?
will wait till the validation of these future promsing molecular genetic biomarkers we need more prosepctive studies to confrim thier value in the field of the kidney transplant we still depend on the clinical and histopathological evidence for diagnosis and treatment of steriod resistant AR . This review article shedding lights for the future move toward the use of noninvasive molecular biomarkers for early diagnosis and timely intervention to treat AR awhich can impact the graft survival and outcome.
Last edited 3 years ago by saja Mohammed
Sahar elkharraz
3 years ago
Kidney transplant is the best option in patients with ESRD and successful rate of transplant reach to 90%. despite improvement in outcome of graft but still acute alo graft rejection within one year of transplant can happen at any time. Acute mediated rejection mainly due to cellular rejection and treated with pulse therapy of steroid & shows reverse graft rejection within 15 days. it’s difficult to predict graft rejection because early detection can manifested by clinically and histologically and early treatment can prevent graft loss. but in 20% of cases shows resistance to steroid. once steroids resistance predicated should be add IV ATG to avoid graft loss.
steroid resistance can predicted after initiation of steroid shows fail to decrease level of creatinine & histological show vascular injuries ( Banff calss II), T cell infiltration.
Steroid is potent anti inflammatory and immunosuppressive drug. Resistance to steroid can happen due to disturbance in regulating of steroid to suppress pro inflammatory genes ( chemokine / cytokines and molecular adhesion), inside nucleus of cell. In first 5 days from initiation of steroid; it’s difficult to differentiate from steroid response & resistance after 5 days if fail to reduce creatinine level indicating patients have resistance to steroid and should start ATG.
there’s Immunological and non immunological bio markers which are associated with steroid resistance:
Cytotoxic T cell lymphocytes & natural killer
Macrophage infiltration
B cell infiltration (CD20)
non immunological factors:
Metalloproteinase I // Metallothioneins
Coagulation factors Ii receptor
micro RNA transcription .
In our Practice should be monitoring serum creatinine daily & put possibility of drug resistance to steroid if fail decrease serum creatinine and should start ATG and plain patient for renal biopsy and according to banff classification detects type of rejection.
Huda Al-Taee
3 years ago
Acute rejection (AR) is a dominant risk factor for adverse graft outcomes. Even after the introduction of immunosuppressive medication, AR continues to be a primary cause of renal allograft failure. Various AR parameters determine the risk for adverse graft outcomes, including timing, recurrence, severity, and therapy sensitivity of AR episodes.
Treatment of AR episodes consists of:
synthetic corticosteroid: previously, increased doses of prednisolone were the primary treatment for AR, but because of the toxic SE, treatment shifted to IV methylprednisolone.
polyclonal and monoclonal antibodies: ATG causes depletion of T cells and other lymphocytes through various mechanisms; it is an effective treatment with high graft survival rates, but it has SE such as leukopenia, cytokine release syndrome, and viral infection, so it is reserved for steroid-resistant cases. Another drug is OKT3 which also depletes T cells, but it has been withdrawn due to low efficacy and higher incidence of SE than ATG.
Immunoregulatory effect of GCs:
Corticosteroids have both anti-inflammatory and immunosuppressive effects. These effects are obtained through direct and indirect regulation of immune-related gene transcription. The major action of GC is the suppression of inflammatory genes encoded for cytokine, chemokines, adhesion molecules, and inflammatory enzymes, GC also increases the expression of anti-inflammatory cytokines and transcription mediators, they can also prevent leukocyte migration, induction of lymphocytes death, and effect on the growth and lineage commitment of T cells.
steroid resistance:
Around 20-30% of rejection episodes can not be reversed by GC alone, and this poor response can happen in recipients of other organs such as liver, lung, heart. More rigorous immunotherapy is needed in such a case, such as ATG, which treat 70-90% of the cases.
AR episode is considered steroid-resistant when the patient’s serum creatinine level does not return to within 120% of the pre-rejection baseline value after pulse therapy with GC within 14 days after the start of the steroid therapy.
Assessment of risk for steroid resistance:
clinical and pathological indicators: such as acute vascular rejection, the presence of mononuclear cells at endothelial cells of large and small vessels in the graft, the presence of immune response directed against the microvasculature, more extensive leukocyte infiltration into the peritubular capillaries, C4d deposition.
prognostic biomarkers: immune biomarkers: certain types of lymphocytes infiltration was associated with poor graft outcomes such as cytotoxic lymphocytes, NK cells, B cells and macrophages. The prognostic value of immune biomarkers is hampered by molecular heterogeneity among kidney biopsy samples with AR. Non immune biomarkers: a link between zinc regulation and resistance to steroids. Combination of immune and non-immune biomarkers in multivariate prediction model could enhance sensitivity and specificity, and facilitate risk assessment of steroid resistance in AR cases.
Glucocorticoid receptor expression: the anti-inflammatory and immunosuppressive action of GC are mediated by ligand-dependent GR, so differences in response to treatment may be explained by GR expression. in addition, genetic variability may play a role. further studies are needed to confirm the role of GR in GC resistance.
Future perspectives:
validation of the prognostic value of biomarkers
microRNA expression as a novel biomarker for response to steroid therapy
Heba Wagdy
3 years ago
Acute renal allograft rejection negatively affect the long-term graft outcome, the diagnosis depends on clinical and histopathological assessment of graft biopsy, which can determine the severity but can’t predict the response to treatment.
Biomarkers of glucocorticoid (GC) resistant rejection may help in assessing the risk of poor graft outcome and the probability of response to anti-rejection treatment. Treatment of acute rejection:
IV methylprednisolone is the first line of treatment with less side effects than oral prednisolone.
ATG therapy is mainly used for treatment of steroid resistant acute rejection and recurrent cases due to the risk of complications. Steroid resistant:
It is a complex and multi-factorial condition, 25-30% of recipients may have rejection episodes which can’t be reversed with steroids and need more vigorous immunosuppression.
acute rejection episode is considered steroid resistant when serum creatinine fails to return to 120% of pre-rejection baseline within 14 days after pulse steroids.
minimal time period for assessment of response is 5 days after initiation of pulse steroid Prediction of steroid resistance at time of biopsy allow avoiding:
Unnecessary exposure to high dose steroids
Development and progression of graft damage during the period of uder-treatment with steroids. Clinical and pathological indicators of steroid resistant rejection:
Acute vascular rejection is related to resistance to high dose steroid.
Presence of mononuclear cells at endothelial cells of large and small vessels in the graft associated with steroid resistance.
Moderate to severe microvascular destruction responds less adequately to steroid therapy.
Extensive leucocyte infiltration into peritubular capillaries associated with steroid resistance.
It remains difficult to predict the response to steroids according to histopathological assessment. Prognostic biomarkers for steroid resistant rejection:
Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness may provide complementary parameters for risk of adverse graft outcome. Immune biomarkers:
Both T cells and macrophages have important role in response to steroid therapy.
Resistance to GC is associated with increased expression of cytotoxic T lymphocyte, NK cells, B lymphocytes and macrophage signatures.
The extent of CD8+ T cells infiltration within allograft correlated with response to treatment with GC.
Macrophage infiltration in the graft is related to response to GC therapy. Challenges for biomarker identification in clinical context:
Clinical interpretation of these data is difficult as definition of steroid resistance and cohort characteristics vary in different studies, so the prognostic value of proposed immune biomarker can’t be verified. Non-immunological biomarkers:
A recent finding is the link between zinc regulation and steroid resistant acute rejection.
Recipients who express high intra-graft levels of MT and TIMP1 during acute rejection might benefit from extra zinc intake for optimal GC signaling
Coagulation factor II receptor (regulator of intracellular signaling pathways) may affect GC action and need further research to determine the mechanism. Combination of immune and non-immune biomarkers:
No single biomarker can predict the response to steroid treatment.
Combination of biomarkers could improve sensitivity, specificity and predict the response to GC in treatment of acute rejection.
How would this study change your practice?
Steroid resistant acute rejection can’t be predicted through histopathological assessment.
Recipients with acute rejection may benefit from extra zinc intake which may have a role in response to steroid therapy.
Riham Marzouk
3 years ago
Acute rejection AR occurrence negatively affects graft outcome, it occurs more in the first three months post-transplant, once it happens, no one can predict its response to the treatment and extent of its negative impact on the graft outcome.
AR is reduced in incidence after introduction of immunosuppression medications from 90% to 15%, also there is substantial improvement of short-term survival at one year, but long-term survival has marginal improvement at 10 years. in spite of all of these , AR remains the first cause of graft loss, also it affects the occurrence of CAN chronic allograft nephropathy (IFTA) ; interstitial fibrosis and tubular atrophy which leads to graft loss after 1 year.
Treatment of acute renal allograft rejection:
1- Steroid the first medication used to treat and prevent rejection, high dose oral steroid oral prednisolone is required to maintain the status of no rejection or prevent rejection but will induce its toxic GIT side effects because it is required with high doses, so intravenous methylprednisolone used in high dose in induction of immunosuppression hence prevention of rejection and also in treating acute rejection episodes, and associated with less GIT side effects, so it is first line therapy.
2- Second line therapy is ATG antithymocyte globulin which is polyclonal antibody used in induction of immunosuppression and in treating resistant or severe cases of acute cellular rejection, it is antibody depleting agent but has some side effects like pancytopenia, fever, chills, headache, cytokine release syndrome /storm
Steroid has direct and indirect effects on immune related gene transcription, it suppress inflammatory genes which are 10-100 genes and also it increase anti-inflammatory cytokines, and it induces apoptosis of lymphocytes and prevent leucocyte migration hence prevent all consequences of acute rejection.
Steroid resistance :
Diagnosis of steroid resistance primarily relies on posttransplantation follow-up of clinical parameters reflecting renal allograft function. An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy
The minimal time period for assessment of the response to steroids is five days after initiation of the pulse therapy [
This untreated resistant cases can lead to chronic graft loss, so ATG should be used to treat these resistant cases.
Pathological indicators of steroid resistant cases:
1- Acute vascular rejection
2- presence of mononuclear cells at endothelial cells of large and small vessels in the graft
3- immune response directed against the microvasculature ; Patients with moderate to severe microvascular destruction respond less adequately to steroid therapy compared to patients with only mild destruction of the microvascular endothelium
4- more extensive leukocyte infiltration into the peritubular capillaries (PTC)
5- C4d deposition
my practice ; if there is no or little response to 3- 5 days pulse steroid, will do biopsy and start ATG until the result of biopsy appeared which may result in AMR and need plasmapharesis and ivig
Doaa Elwasly
3 years ago
Impact of acute rejection on graft outcome
The one-year graft survival rates exceeded 90% on short-term , the long-term graft outcome advance is not enough .
10% of graft failure was due to acute renal allograft rejection.
Renal interstitial fibrosis and tubular atrophy (IFTA) is the most common cause of chronic allograft failure after the first post-transplant year.
Risk of graft failure increases with time after transplantation , being more common to occur 3 months or more after transplantation , also those with recurrent AR episodes, and those with acute vascular rejection and cases resistant to therapy have a higher risk of graft failure . Acute renal allograft rejection treatment
Therapeutic options for AR episodes treatment -Corticosteroids
Both IV and oral steroids are successful in treating AR ,in fact pulse therapy with intravenous methylprednisolone has less side effects than oral prednisone therapy that is why intravenous pulse therapy with high-dose methylprednisolone is applied.
–Polyclonal and monoclonal antibody
ATG derived from rabbits and horses injected with human lymphocytes .
ATG therapy depletes circulating T cells by antibody- and complement dependent lysis and inducing apoptosis.
ATG is effective but can lead to side effects as leukopenia, cytokine release syndrome, and viral infections because of that it is saved for treating steroid resistant and recurrent AR. Immunoregulatory effects of corticosteroids
Is due to it’s anti-inflammatory and immunosuppressive effects through direct and indirect regulation of immune-related gene transcription.
It’s main action is the suppression of inflammatory genes including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes and increase the expression of anti nflammatory cytokines . Corticosteroid signaling
After administration, GCs diffuse across the cell membrane and bind to the cytoplasmic GR, the cytoplasmic GRα is associated with an inhibitory complex. This association stabilizes the hormone-responsive form of the receptor when ligand-induced activation occurs , the GR changes and dissociates enabling rapid translocation of the GC-GR complex to the nucleus regulating gene transcription through direct and indirect signaling pathways. These pathways inhibit the transcription of pro-inflammatory molecules, it’s alteration can lead to steroid resistance. Steroid resistance
Steroid-resistant rejection cases are treated with ATG, with response rate of 70 to 90%
steroid resistance is diagnosed after pulse steroid therapy is given for 14 days and the serum creatinine level do not return to within 120% of the pre-rejection baseline value ,meanwhile 5 days are needed after start of pulse therapy to assess the response. Assessment of risk for steroid resistance Indicators of steroid resistance
Acute vascular rejection and the presence of mononuclear cells at endothelial cells of large and small vessels in the graft is related to resistance to high-dose steroid therapy .
Cases with mild destruction of microvascular endothelium respond better to steroid therapy more than those with moderate to severe destruction.
Circulating leukocytes target HLA molecules expressed on the PTC, leads to cellular rejection. Prognostic markers of steroid resistance rejection Immune biomarkers
The presence of T lymphocytes and natural killer cells are the first to appear and the extent of CD8 infiltration correlates with response to steroids .
B cell infiltration in a renal allograft can differentiate between steroid resistant and steroid response AR .
The presence of intraglomerular and interstitial macrophages are prognostic markers for steroid resistance also macrophage infiltration is associated with intimal arteritis and C4d deposition.
The expression of a broad panel of immunological markers within renal allografts with steroid responsive or steroid resistant AR was evaluated.
A combination of T cell activation markers CD25:CD3ε ratio and lymphocyte activation gene-3 (LAG-3) provides a prognostic value for assessing steroid response. Non immunological biomarkers
The resistance to steroids therapy was associated with Zinc regulations indicating that Zn can be given to reduce steroid resistance
Intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is accompanied with steroid resistance .
TIMP1 can diminish the zinc-requiring anti-inflammatory effects of the GR. Combination of biomarkers
Can increase sensitivity and specificity, and enables better risk assessment of steroid resistance . Glucocorticoid receptor expression
Response variation to treatment with GCs can be due to variations in GR expression. Future perspectives Validation of the prognostic value of biomarkers MicroRNA expression as a novel biomarker for response to steroid therapy Non-invasive methods for monitoring of graft outcome
This study can change my practise
by shedding light on
-the new prospectives of searching for non invasive prognostic markers for steroid resistance other than invasive biopsy by trying to combine both immunological and non immunological biomarkers and investigating new blood and urinary markers
-Zinc was recommended to be used for steroid resistance cases
mai shawky
3 years ago
· Acute rejection (AR) represents a great threat on allograft survival, its incidence nowadays about 15 % and considered responsible for graft loss in 10 % of kidney transplant recipients. It increase risk of chronic immune mediated graft damage (transplant glomerulopathy), previously known chronic allograft nephropathy (CAN).
· Initially, steroids addition and optimization of maintenance immunosuppressive therapy used to treat AR. However, IV pulse steroids are now 1st line of treatment of AR.
· Steroids act through binding to cytoplasmic receptors (GR), then conformational changes then translocation to nuclear receptors to control many transcription genes to:
o Increase transcription of anti-inflammatory mediators.
o Decrease expression of pro-inflammatory mediators as cytokines and chemokines.
· Diagnosis of clinical AR depends mainly on clinical parameters (rising creat) and the golden standard is allograft biopsy proven histopathological damage of the graft.
· 20-30% of AR episodes are steroid resistant (creatinine does not decrease to 120% of baseline, or remained increased by more than 20 % of basal level ) after pulse steroids after 14 days of pulse steroids.
· The definition of steroid refractory AR remains variable and cut off level duration to assess response to pulse steroids also variable, but most of studies concluded that 5 days is minimal duration to determine steroid response.
· Those cases can be treated by r ATG with effective response in 70-90 % of cases.
· Some clinical predictors of steroid refractory AR:
o Late onset after 3 months, recurrent episodes of AR, no response to pulse steroids after 5-7 days.
· Some histopathological evidence of steroid resistance are :
o Vascular rejection (Banff II or III).
o Evidence of microvascular inflammation.
o Mononuclear infiltration at endothelium of blood vessels
o Extensive leukocytes infiltration in ptc.
o +ve c4d in ptc (indicating activation of complement system).
· Early detection of steroid resistant AR is crucial to avoid toxic effects of large steroid dose and to allow start of alternative therapy to salvage the graft. Hence, continuous research to find biomarkers for prediction of steroid resistance rather than pathological markers.
· Till now, no single biomarker with adequate sensitivity and specificity.
· Immunological biomarkers as:
o Increased B cell markers as CD 20 and Ig.
o Increased CD 8+ T cytotoxic and NK cells markers (high fasL mRNA, or decreased urine foxp3).
o T cell activation marker (CD25:CD3)
o Increased marker of macrophageinfiltration (CD68).
· Non immunological markers:
o Increased expression of metallothionines (MT) which decrease zinc ions required for GR signaling.
o Inhibition of metalloproteinase.
o Role of GR downregulation which is evident in nephrotic syndrome and bronchial asthma, not proved in field of transplantation (need further research).
Q. implications of the study?
· Combined clinical and pathological evidence are the only or widely used tools till today to detect steroid resistant rejection as early as possible
· Further studies to detect best biomarker to detect steroid refractory AR.
· Zinc supplementation may help in improving response to steroids.
Last edited 3 years ago by mai shawky
Sherif Yusuf
3 years ago
Acute rejection impact on the kidney
· Chronic allograft nephropathy and IFTA
· Reduced graft survival and graft loss
Episodes of acute rejection whether it is early or late are generally associated with poor graft survival but not all episodes are associated with the same impact on the kidney , this may depend on some factors:
Timing of rejection : later onset of rejection (>3 months post transplant) was associated with worse graft outcomes
Severity of rejection (Banff grade II with evidence of vascular rejection has more severe impact on graft failure than lower grades)
Number of rejection episodes
Sensitivity to treatment especially steroids
Degree of recovery of kidney function after treatment
Current treatment of acute TCMR
1. Pulse methylprednisolone followed by oral prednisolone taper
2. Augmentation of immunosuppressive medications
3. ATG (deplete T cells) used only in TCMR with Banff grade > IA especially if resistant to CS
Corticosteroids in treatment of AR
CS constitutes the first line of treatment of AR
Iv steroids has lower side effects when compared to oral prednisolone
The main mechanism of action of corticosteroids in the treatment of rejection includes anti-inflammatory , immunosuppressive effect
20-30 % of TCMR rejection episodes are steroid resistant and needs ATG for salvaging the kidney
Steroid resistance is defined as failure of the serum creatinine to return to 120% of the baseline before rejection after 2 weeks of pulse steroids
Improvement of serum creatinine usually occur in steroid sensitive as well as steroid resistant AR during the first 5 days, after 5 days patient with steroid sensitive AR tend to improve while those with steroid resistant AR episodes tend to either stabilize at higher creatinine level or deteriorate
This time delay to asses steroid sensitivity may have bad impact on the graft thus it is important to anticipate steroid resistance, the following are parameters that can be used to assess steroid responsiveness :
1. The presence of acute vascular rejection in graft biopsy
2. Presence of mononuclear cells at the vascular endothelium of small and large blood vessels
3. Moderate to severe microvascular endothelial destruction
4. Aggressive inflammatory cell infiltration of PTCS
5. C4d staining of PTCS
6. Immunologic biomarkers : since the Type of infiltrating lymphocyte population may alter steroid responsiveness, cytotoxic T lymphocyte (CD 8 +), NK cells, macrophages (CD68), B lymphocytes (CD 20)are associated with steroid resistance, immune biomarkers includes CD25:CD3ε ratio andLAG-3
7. Non immunologic biomarkers : most important is metallothioneins (MT) and tissue inhibitor ofmetalloproteinase-1 (TIMP1) which are responsible for zinc regulation, it was found that increase graft expression of both may be associated with steroid resistance, thus there may be a rule of zinc supplementation in patients who express high intragraft levels of MT and TIMP1 during AR
8. Glucocorticoid receptor expression but currently no correlation found between steroid responsiveness sand GC receptors
How would this study change your practice?
Currently we initiate immunosuppression according to Banff grade and C4d staining which will anticipate steroid responsiveness
Mild cell mediated rejection Banff 1/2A is associated with good graft outcome
Banff 1A is usually steroid sensitive and pulse cortecosteroids and augmentation of immunosuppression usually revers rejection
Banff 2A and good response to corticosteroids but may need addition of ATG to reverse rejection
Any histologic severity greater than Banff 1 A (except 2A) was associated
with poor prognosis
Biomarker use is complex and not highly sensitive or even specific
Can you explain the following statement” Steroid resistance is defined as failure of the serum creatinine to return to 120% of the baseline before rejection after 2 weeks of pulse steroids”
If creatinine level for example is 1mg/dl before rejection (baseline) and reach to 3mg/dl after rejection, and we started steroid for the treatment of AR, if serum creatinine fail to return to 1.2 mg/dl (120% of the baseline) at 2 weeks after treatment of rejection, this is called steroid-resistant AR.
This definition is not practical since I should wait for 2 weeks to assess steroid responsiveness, in practice we start treatment with either steroids or steroid + ATG according to Banff classification from the start with an assessment of creatinine daily or every other day according to the severity and after discharge, creatinine is monitored in weekly basis till reaching the baseline.
Last edited 3 years ago by Sherif Yusuf
Abdulrahman Ishag
3 years ago
Please give a summary of this article;
Resistance to steroid therapy is a complex and multi factorial condition, in which both immunological and non-immunological factors can be involved. The response to high-dose corticosteroid therapy for the treatment of acute renal allograft rejection correlates with the expression level and characteristics of T cells and macrophages infiltrating into the renal allograft. These findings indicate that steroid resistance resides in specific cell populations and is not a feature of all lymphocytes.
The therapeutic effects of synthetic GCs for the treatment of acute renal allograft rejection are attributed to their anti-inflammatory and immunosuppressive effects.
The major action of GCs is the;
1- suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and in flammatory enzymes .
2- down regulation of pro-inflammatory genes, GCs increase the expression of anti- inflammatory cytokines and transcription mediators].
3- glucocorticoid (GC) therapy can suppress AR through a variety of other mechanisms, including the prevention of leukocyte migration, induction of cell death in lymphocytes, and effects on the growth and lineage commitment of T cells .
4- indirect suppression(trans-repression) of pro-inflammatory genes that are activated during AR .
An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy . The minimal time period for assessment of the response to steroids is five days after initiation of the pulse therapy .
Prediction of steroid resistance at the time of biopsy could;
1- prevent unnecessary exposure to high-dose corticosteroid therapy.
2- The development and progression of irreversible nephron loss during the period that steroid resistant AR is undertreated with steroids alone could be avoided.
Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness could provide complementary parameters for assessing the risk of adverse graft outcome
1. Immune biomarkers; allograft-infiltrating inflammatory cell types, were found to be informative with respect to therapy response (immune (CD25:CD3ε ratio, LAG-3) .
2- Non-immunological biomarkers (MT-1, TIMP1, F2R)
3- Combination of immune- and non-immune biomarkers
combination of biomarkers in a multivariate prediction model could enhance sensitivity and specificity, and facilitate risk assessment of steroid resistance in patients suffering from AR.
4-Glucocorticoid receptor expression; Decreased GR expression has been implicated as a cause of steroid resistance in a wide variety of diseases, including nephrotic syndrome , acute lymphoblastic leukemia , and asthma . The ob-served differences in GR expression between responders and non responders might be a reflection of varying levels of GR autoregulation.
Clinical implications;
1-Investigations of immune-related biomarkers revealed that both T cells and macro- phages play an important role in the response to steroid therapy. Combined, these findings indicate that steroid resistance resides in specific cell populations. This may guide the therapeutic approaches for treatment of steroid-refractory AR episodes.
2- Zinc regulation may play a role in the response to steroid therapy during AR. Kidney transplant recipients who express high intragraft levels of MT and and TIMP1 during AR might benefit from extra zinc intake for optimal GC signaling.
3- Molecular heterogeneity among biopsy samples may explain the difficulties in validating the prognostic value of previously proposed biomarkers for steroid resistance. In addition, it demonstrates the importance of using internal and external validation techniques to verify the robustness of potential biomarkers.
4- a multivariate approach could identify patients with insufficient response to anti-rejection treatment with GCs, who would benefit from immediate ATG treatment.
5-Availability of a multivariate biomarker model in the clinic may lead to reduced exposure to high-dose corticosteroid therapy. More importantly, it may help avoid the development and progression of irreversible nephron loss during the period that steroid-refractory AR is undertreated with steroids alone.
6-multivariate models provide insight into the causative mechanisms in steroid-refractory AR episodes, which may guide the development of novel therapeutic approaches.
Future perspectives;
1- Validation of the prognostic value of biomarkers.
The prognostic value of the biomarkers should be confirmed in a prospective study before they can be introduced into the clinic.
2- MicroRNA expression as a novel biomarker for response to steroid
therapy Because of their relatively stable expression, microRNAs are emerging as potential biomarkers. Analysis of microRNA expression profiles in renal biopsies may lead to the identification of novel prognostic biomarkers for the outcome of acute renal allograft rejection.
3- Non-invasive methods for monitoring of graft outcome
Identification of molecular markers in blood and urine may provide means to monitor graft function more frequently, which could lead to earlier detection of graft dys function and timely intervention of the immune process.
How would this study change your practice?
I understand the importance of early diagnosis of steroid resistant acute rejection ( to prevent unnecessary exposure to high corticosteroid and development of irreversible nephron loss during period that steroid resistant AR undertreated with steroids alone could be avoided ) and kidney transplant recipients may benefit from additional zinc intake to optimize GC signaling.
Thanks Abdulrahman for your reply Let us think about the definition of steroid resistant rejection. Ary you happy with the definition mentioned in the given article?
Incidence of AR from over 80% in the 1960s to below 15% nowadays.
one-year graft survival rates in excess of 90%.
Approximately 50% of grafts from deceased donors and 30% of grafts from living donors fail within ten years after kidney transplantation .
The graft attrition rates after the first year are between 3% and 5% annually. This is mainly due to death with a functioning graft and chronic allograft failure.
AR is also correlated with the development of chronic allograft failure.
Risk of graft failure –
increases as the time between engraftment and occurrence of AR increases, and is most pronounced with late AR episodes (occurring 3 months or more
after engraftment) .
patients experiencing repeated AR episodes are at greater risk of adverse graft outcome than those with no or only one episode .
patients with acute vascular rejection (Banff classification grade II) have a higher risk of graft failure compared to patients with acute tubulointerstitial rejection.
rejection episodes unresponsive to AR treatment.
Treatment of acute renal allograft rejection
Corticosteroids – pulse therapy with intravenous methylprednisolone is associated with fewer side effects than oral prednisone therapy.
Polyclonal and monoclonal antibodies- ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR.
Immunoregulatory effects of corticosteroids-
GCs increase the expression of antiinflammatory cytokines and transcription mediators
prevention of leukocyte migration,
induction of cell death in lymphocytes,
effects on the growth and lineage commitment of T cells .
The actions of GCs are mediated by the intracellular glucocorticoid
receptor (GR).GRα is activated by GC binding and mediates most of the
known immunomodulatory effects. GRβ isoform expresses a different C-terminal region which inhibits GC binding.
Steroid resistance
in approximately 25 to 30% of the patients the rejection episode cannot be
reversed with corticosteroid therapy alone.
An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy .
ATG treatment is generally required.
the minimal time period for assessment of the response to steroids is
five days after initiation of the pulse therapy.
This 5-day period is also the average time delay used by clinicians before considering a rejection as being steroid resistant.
Assessment of risk for steroid resistance-
Clinical and pathologic indicators of steroid resistant rejection-
Acute vascular rejection on biopsy.
presence of mononuclear cells at endothelial cells of large and small vessels in the graft .
presence of an immune response directed against the microvasculature.
more extensive leukocyte infiltration into the peritubular capillaries (PTC).
C4d deposition in PTC has been associated with steroid resistance.
Prognostic biomarkers for steroid resistant rejection
Immune biomarkers –
Cytotoxic T lymphocytes and NK cells.
B lymphocytes
Macrophages
combination of T cell activation markers CD25:CD3ε ratio and lymphocyte activation gene-3 (LAG-3) offers an improved prognostic value for assessing steroid response.
Non-immunological biomarkers-
Relatively high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with steroid resistance. Increased intragraft MT expression may lead to removal of zinc ions that are normally used in GC signaling.
Differences in response to treatment with GCs may be explained by variations in GR expression.
The results of a questionnaire submitted to 17 transplant centers by Cantarovitch and Soulillou indicated that the mean period before considering a rejection as steroid resistant ranged from 3 to 7 d (median, 5 d).
Steroid-Resistant Kidney Transplant Rejection: Diagnosis and TreatmentH. ANDREAS BOCK
Steroid resistance has been defined differently by different groups, but most have defined it as non-response to therapy after 3-7 days (median 5 days). A study revealed that the creatinine response to steroid sensitive and steroid resistant rejection diverges after 5 days of steroids, hence if no response to 5 days of steroids, next line of treatment (ATG) should be given.
Waiting for 14 days to see the response is not prudent as the response to therapy would be better if initiated early.
Reference: 1) Bock HA. Steroid-resistant kidney transplant rejection: diagnosis and treatment. J Am Soc Nephrol. 2001 Feb;12 Suppl 17:S48-52. PMID: 11251032. 2) Shinn C, Malhotra D, Chan L, Cosby RL, Shapiro JI. Time course of response to pulse methylprednisolone therapy in renal transplant recipients with acute allograft rejection. Am J Kidney Dis. 1999 Aug;34(2):304-7. doi: 10.1016/s0272-6386(99)70359-8. PMID: 10430978.
Steroid resistance AR:
Acute rejection (AR) is a major cause of graft loss. It is primarily a cellular type directed against mismatched donor antigens expressed on the allograft, and generally occurs in the early post-transplant period, especially in the first 3 months. In order to prevent adverse graft outcomes, reliable and timely detection of AR is needed. Diagnosis of AR depends on clinical parameters and biopsy findings. Most cases are asymptomatic and the only finding is an increase in serum creatinine is an indicator of graft function decline. Banff classification is used to diagnose AR and its severity. Anti-rejection treatment response is difficult to predict based on clinical and histopathological findings, and biomarkers could add additional parameters for assessing the risk of adverse graft outcomes.
Impact of acute rejection on graft outcome
With the introduction of immunosuppressive medications, the AR incidence drops, although it remains a major factor contributing to adverse graft outcomes. AR episode also correlates with a significant reduction in long-term allograft survival, with the development of chronic allograft failure (CAN, or IFTA). Various parameters of AR determine the level of risk for adverse graft outcomes including timing, recurrence, severity, and therapy sensitivity of AR episodes.
Late AR that occurs after 3 months carry a poorer prognosis than early, recurrent episode worse than one or no AR. Banff grade II; AR with vascular rejection has a higher risk of graft loss as compared with Banff grade I. as well, AR that does not respond to therapy has a bad prognosis
Treatment of acute renal allograft rejection
Many therapeutic options are available for the treatment of AR. AR can still occur despite optimization of HLA compatibility and the use of induction therapy and maintenance immunosuppression.
These drugs include:
1- Synthetic corticosteroids
Intravenous pulse therapy with high dose-methylprednisolone nowadays has become the first-line therapy for AR in most transplant centres.
2- Polyclonal and monoclonal antibodies
ATG is an effective treatment of AR with high graft survival rates, although; ATG has many complications, such as leukopenia, cytokine release syndrome and viral infections. Due to its complications, ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR.
OKT3 is a monoclonal antibody-based treatment directed to the CD3 molecules, which is associated with T cell receptors (TCR). So, it can modulate TCR resulting in depletion of T cells. OKT3 has been withdrawn from the market due to its lower efficacy and higher side effects compared to ATG.
Most AR episodes can be adequately treated with high-dose corticosteroids. However, about 25 to 30% of these episodes cannot respond to steroids. In these cases, treatment with ATG can result in a salvage rate of 70 to 90%.
Diagnosis of steroid resistance primarily relies on post-transplantation follow-up of clinical parameters reflecting renal allograft function. An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy. If steroid response occurs five days after initiation of the pulse therapy is called a steroid-responsive case.
This 5-day period is also the average time delay used by clinicians before considering a rejection as
being steroid-resistant. Incomplete restoration of graft function in steroid-resistant rejection may lead to progression of chronic damage to the graft and has a detrimental effect on graft outcome.
Assessment of risk for steroid resistance:
Steroid resistance risk prediction at the time of biopsy could prevent unnecessary exposure to high-dose corticosteroid therapy as well, irreversible nephron loss could be avoided.
Clinical and pathologic indicators of steroid-resistant rejection
Clinical parameters and histopathological assessment of kidney biopsies remain the golden standard for evaluating short- and long-term graft outcomes.
Several parameters have been associated with unresponsive to steroid treatment:
1- Acute vascular rejection.
2- Presence of mononuclear cells at endothelial cells of large and small vessels in the graft.
3- Presence of an immune response directed against the microvasculature.
4- Moderate to severe microvascular destruction respond less adequately to steroid therapy.
5- Extensive leukocyte infiltration into the peritubular capillaries (PTC).
6- Circulating leukocytes target HLA molecules expressed on PTC, which results in to cellular rejection.
7- Presence of DSA against HLA molecules, leading to local complement activation and humoral rejection.
8- C4d deposition in PTC has been associated with steroid resistance.
Prognostic biomarkers for steroid-resistant rejection
Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness could provide complementary parameters for assessing the risk of adverse graft outcomes.
a- Immune biomarkers:
Resistance to steroids has been associated with increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B-lymphocyte-, and macrophage signatures.
b- B lymphocytes
The extent of B cell infiltration within the renal allograft was shown to discriminate between steroid-resistant and steroid response AR episodes. Steroid-refractory AR expressed increased intragraft levels of B cell marker CD20 and B-lymphocyte-associated immunoglobulins.
c- Macrophages:
Immunostainings for CD68 revealed the presence of intraglomerular and interstitial macrophages during AR as prognostic markers for steroid resistance and graft outcome. Also, macrophages have been associated with intimal arteritis and C4d in the PTC which are in themselves associated with resistance to anti-rejection therapy.
Challenges for biomarker identification in a clinical context
The definition of steroid resistance varies widely between studies, also, the patient’s character, the timing of AR from transplantation, and differences in immunosuppression therapy, all make interpretation of these biomarkers challenge.
Non-immunological biomarkers
A relatively novel finding is the link between zinc regulation and resistance to anti-rejection treatment with steroids. Relatively high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with steroid resistance.
Combination of immune- and non-immune biomarkers
The underlying mechanisms for steroid-resistant acute rejection are multiple therefore, no single biomarker has been able to predict the response to steroid treatment with both high sensitivity and high specificity.
Glucocorticoid receptor expression
The observed differences in GR expression between responders and non-responders might be a reflection of varying levels of GR autoregulation.
Clinical implication:
Steroid resistance is a complex and multifactorial condition, that includes both immunological and non-immunological factors. Both T cells and macrophages play an important role in the response to steroid therapy. Zinc regulation may play a role in the response to steroid therapy during AR. Kidney transplant recipients who express high intragraft levels of MT and TIMP1 during AR might benefit from extra zinc intake for optimal GC signalling.
Non-invasive methods for monitoring graft outcome
Graft biopsy is the gold standard for the diagnosis of graft outcomes. But it is mainly performed on clinical indications s an invasive procedure. Identification of molecular markers in blood and urine may provide means to monitor graft function more frequently, which could lead to earlier detection of graft dysfunction and timely intervention of the immune process.
Conclusion:
Steroid-resistant AR is a complex and multifactorial condition. Graft infiltration with T-lymphocytes and macrophages correlates with steroid resistance AR which means that AR is related to specific cells population. Zinc regulation and drug metabolism may play a role in the response to steroid therapy during acute renal allograft rejection. Kidney recipients may benefit from adding zinc to optimise GC signalling.
How to change this, my practice?
I will increase the suspicion of steroid resistance AR if the graft function indicators do not subtle by the 5 days of steroid use.
· Acute rejection (AR) is a dominant risk factor for adverse graft outcome . Approximately 50% of grafts from deceased donors and 30%
of grafts from living donors fail within ten years after kidney transplantation.
Various parameters of AR determine the level of risk for adverse
graft outcome including the timing, recurrence, severity, and therapy
sensitivity of the AR episode .
· Treatment of acute renal allograft rejection :good investigation and u sing of immunosuppression drugs lead to decrease incidence of acute rejection .
· 1-Synthetic corticosteroids intravenous pulse therapy with
high-dose methylprednisolone has become the first-line therapy for
AR in most medical centers .
· Polyclonal and monoclonal antibodies ATG therapy causes depletion of circulating T cells and other leukocytes through various mechanisms, including antibody- and complement dependent lysis and the induction of apoptosis but it associated with increase risk of infection..ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR .
· The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes.
· Steroid resistance :About 25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone . Renal allograft recipients with steroid-refractory rejection are generally treated with ATG, which results in a salvage rate of 70 to 90% .An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy .
· Clinical and pathologic indicators of steroid resistant rejection :1-Acute vascular rejection 2-presence of mononuclear cells at endothelial cells of large and small vessels in the graft 3-extensive leukocyte infiltration into the
peritubular capillaries (PTC .4- C4d deposition
· .Prognostic biomarkers for steroid resistant rejection :
· 1-. Immune biomarkers
· 2-Non-immunological biomarkers.
· 3-Combination of immune- and non-immune biomarkers
· 4-Glucocorticoid receptor expression
· Methods for monitoring of graft outcome :1-renal biopsies
· 2-Blood test 3-urine analysis .
· This information will improve our practice with best flow up and management to the patient .
Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection.
About 25 to 30% of the renal allograft rejection not responded to steroid treatment alone. Majority acute graft rejection can be treated with high dose steroid. Renal transplant recipients with steroid-refractory rejection may be treated with ATG, which results in a salvage rate of 70 to 90%. Factors associated resistance to therapy in graft rejection include presence of mononuclear cells at endothelial cells of large and small vessels in the graft, presence of an immune response directed against the microvasculature, moderate to severe microvascular destruction, extensive leukocyte infiltration into the peritubular capillaries and C4d deposition in PTC has been associated with steroid resistance. The prognostic markers associated with steroid resistant include increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophages. On the other hand, increase metallothioneins and tissue inhibitor of metalloproteinase-1 at graft biopsy is associated with steroid resistance. Increased expression of metallothioneins may lead to inhibition of the anti-inflammatory effects of zinc-dependent recruitment of HDAC-2 by the GC-GR complex. microRNAs are emerging as potential biomarkers for the outcome of acute renal allograft rejection. In conclusion, refractory to steroid treatment in acute graft rejection involve complex mechanism and due multifactorial conditions. Zinc regulation and drug metabolism may affect the response to steroid treatment in graft rejection. Thus, , kidney transplant recipients with graft rejection may benefit from additional zinc intake to optimize GC signaling.
Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection
Acute rejection (AR) is a dominant risk factor for adverse graft outcome. AR is primarily a cellular immune response directed against mismatched donor HLA antigens present on the allograft cells.AR usually occurs during the early post-transplant period, with the highest risk in the first 3 months. Detection of AR in time is important for the prevention of adverse graft outcome. Diagnosis of AR episodes through laboratory and histopathological diagnosis of graft biopsy samples.
Most patients who develop AR episode are asymptomatic and present
only with an increase in serum creatinine levels as an indicator of
a decline in renal graft function.
Impact of acute rejection on graft outcome
The incidence of AR episodes is reduced with the introduction of new immunosuppression era from over 80% in the 1960s to below 15% nowadays. As well as, the short term graft survival has been improved, with one-year graft survival rates in excess of 90%.
Despite these advances in short term graft outcome, the long-term
graft outcome improved only marginally over the past two decades. AR
continues to be a primary cause of renal allograft failure. Approximately
10% of all graft losses are directly caused by acute renal allograft rejection. patients with acute vascular rejection (Banff classification grade II) have a higher risk of graft failure compared to patients with acute tubulointerstitial rejection (Banff classification grade I). AR is also correlated with the development of chronic allograft failure. Renal interstitial fibrosis and tubular atrophy (IFTA).
Treatment of acute renal allograft rejection
Several therapeutic options are available for treatment of AR episodes.
Synthetic corticosteroids
Treatment of AR with high doses of oral prednisone was effective but with toxic side effects, such as gastrointestinal bleeding and increased susceptibility to infection. To prevent these complications, the treatment was switched to intravenous methylprednisolone. In comparison of the two regimens revealed that both glucocorticoids are equally successful in reversing AR. However, pulse therapy with intravenous methylprednisolone is associated with fewer side effects than oral prednisone.
The therapeutic effects of synthetic steroids for the treatment of acute
renal allograft rejection are attributed to their anti-inflammatory and
immunosuppressive effects. The actions of steroids are mediated by the intracellular glucocorticoid receptor.
Polyclonal and monoclonal antibodies
anti-thymocyte globulin (ATG), which obtained from horses or rabbits immunized with human lymphocytes, as a treatment of allograft rejection. ATG
therapy causes depletion of circulating T cells and other leukocytes
through various mechanisms, including antibody and complement dependent
lysis and the induction of apoptosis. ATG is an effective treatment of AR with high graft survival rates. However, ATG can induce complications, such as leukopenia, cytokine release syndrome,and viral infections. ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR.
Steroid resistance AR
Most of acute renal allograft rejection episodes can be adequately
treated with high-dose corticosteroids. However, in nearly 25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone. In such cases of steroid resistance, the patient requires more vigorous immunotherapy to reverse the AR episode. Renal allograft recipients with steroid refractory rejection are treated with ATG, which results in a salvage rate of 70 to 90%.
Diagnosis of steroid resistance relies on post transplantation follow up of clinical parameters reflecting renal allograft function. An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to pre-rejection baseline level after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy. The minimal time for assessment of the response to steroids is five days after initiation of the pulse therapy. The 5 days’ time is considered
The control time to assess the action of steroids either responsive or resistant.
Assessment of risk for steroid resistance
Knowing of steroid resistance at the time of biopsy could prevent
unnecessary exposure to high-dose corticosteroid therapy.
In Conclusion, Resistance to steroid therapy is a complex and multifactorial condition, in which both immunological and non-immunological factors can be involved. The response to high-dose corticosteroid therapy for the treatment of acute renal allograft rejection depends on the characteristics of T cells and macrophages infiltrating the renal allograft. These findings indicate that steroid resistance resides in specific cell populations and is not a feature of all lymphocytes.
Summary
Introduction
Immunosuppressive drugs have been used to decrease the incidence of acute rejection in transplant recipients. Short term survival of grafts have grown better. However, risk of graft failure remains.
Mechanism of steroid action
Steroids have been used as part of maintenance immunosuppressive therapy. High doses of steroids can be used to reverse acute renal allograft rejection. However, effects of steroids are not all good. Some of the adverse effects from their use include gastrointestinal hemorrhage, and increased susceptibility to infection. Oral to IV steroids change can possibly reduce risk of these effects.
IV pulse therapy of high dose methylprednisolone can be used as first line therapy for AR.
Steroids have important immunoregulatory effects. These include anti-inflammatory effects. Direct and indirect regulation of immune related gene transcription. Inflammatory genes are suppressed by glucocorticoids. These genes are activated during acute rejection and thus their downregulation, along with the increase of expression of anti-inflammatory cytokines and transcription mediators allows steroids to be an effective tool against AR.
Steroid resistance
Steroids bring about their effects through intracellular glucocorticoid receptor(GR), which is a ligand dependent transcription factor of nuclear receptors. Signaling pathways of GC-GR complex inhibits transcription of pro inflammatory molecules, such as cytokines, chemokine, adhesion molecules, inflammatory enzymes, and receptors of different types and kinds. Alteration in the molecule mechanisms of GR signaling is what leads to steroid resistance.
Steroid resistance is a major issue since AR is often treated with high dose corticosteroids. However, when the patient is resistant to these drugs, it puts the graft at danger. In case of resistance, the patient needs to be treated with even more intensive immunotherapy to rescue the graft back from rejection. ATG is often used with good outcome in steroid resistant patients. Diagnosis of resistance is often made post transplant when the patient does not respond to steroid pulse therapy. This is evidenced by the fact that serum creatinine does not return to within 120% if pre-rejection baseline value within 14 days of starting steroid therapy.
It is necessary to keep in mind that incomplete restoration of graft function can lead to chronic damage and worse outcome.
Assessment of steroid resistance
Biomarkers of steroid resistance are the biomarkers for the molecular and cellular mechanisms involved in graft survival. These include immunological and non-immunological biomarkers.
Immune biomarkers include the following :
Non-immunological biomarkers for steroid resistance include – High intragraft expression of metallothioneins and tissue inhibitor of metalloproteinase 1 during acute renal allograft rejection.
Combination of immune and non-immune biomarkers enhance sensitivity and specificity, allowing better risk assessment of steroid resistance in patients with AR.
Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection
Summary
Introductions:
Acute Rejection is the main cause of graft loss. Despite the success of renal
transplantation, approximately 40% of renal allografts fail within the first 10 years.
Though outcome of graft survival improved with new IS its still has long term effect on
graft survival.
At 10yerrs 50% of DDT have graft loss and 30% of LDT have.
Cause of 10%of graft failure.
AR correlates with a significant reduction in long-term allograft survival.
AR is also correlated with the development of chronic allograft failure.
Various parameters of AR determine the level of risk for adverse graft outcome including
the timing, recurrence, severity, and therapy sensitivity of the AR episode.
Treatment of AR:
Synthetic corticosteroid:
Intravenous is preferred to oral in treatment of AR.
Polyclonal and monoclonal antibodies:
ATG therapy causes depletion of circulating T cells and other leukocytes through various
mechanisms, including antibody- and complement dependent lysis and the induction of
apoptosis.
ATG is an effective treatment of AR with high graft survival rates.
However, ATG can induce complications, such as leukopenia, cytokine release
syndrome, and viral infections.
Due to the risk of complication only used for recurrent and steroid resistant AR.
Steroid resistance:
The majority of acute renal allograft rejection episodes can be adequately treated with
high-dose corticosteroids.
However, in approximately 25 to 30% of the patients the rejection episode cannot be
reversed with corticosteroid therapy alone.
Renal allograft recipients with steroid-refractory rejection are generally treated with ATG.
An AR episode is considered steroid resistant when the patient’s serum creatinine levels
do not return to within 120% of the pre-rejection baseline value after pulse therapy with
corticosteroids within 14 days after the start of the steroid therapy. At that point ATG
treatment is generally required.
The first few days after the start of the steroid treatment are crucial. Analysis of
creatinine courses of steroid-resistant and steroid-responsive cases revealed that the
minimal time period for assessment of the response to steroids is five days after
initiation of the pulse therapy.
Changes in serum creatinine levels were similar between patients with steroid
responsive and steroid resistant AR until day 5, at which time the responders showed
a significant decrease in serum creatinine, while the creatinine level of non-responders.
remained high.
This 5-day period is also the average time delay used by clinicians before considering a
rejection as being steroid resistant.
STEROID IMMUNMODULATION:
Genes activated during AR:
Gene in using cytokins, chemokines, adhesions molecules and inflammatory enzymes.
Gcs increase expression of anti-inflammatory cytokines and transcription mediators,
prevention of leukocyte migration.
Induction of cell death of lymphocytes.
Effect on growth and lineages commitment. Of T. Lymphocytes
Corticosteroid signaling:
The actions of GCs are mediated by the intracellular glucocorticoid receptor (GR), a
ligand-dependent transcription factor of the nuclear receptor superfamily, which is
ubiquitously expressed in most human cells.
The genomic structure of the GR consists of 9 exons.
Alternative splicing in exon 9 generates two C-terminal receptor isoforms, termed GRα
and GRβ.
The predominantly expressed GRα is activated by GC binding and mediates most of the
known immunomodulatory effects.
The signaling pathways of the GC-GR complex inhibit the transcription of pro-
inflammatory molecules, including cytokines, chemokines, adhesion molecules,
inflammatory enzymes, and receptors. Alterations in the molecular mechanisms of GR
signaling may lead to steroid resist .
steroid resistance:
Clinical and pathologic indicators of steroid resistant rejection:
. Several parameters have been associated with response to steroid treatment:
Acute vascular rejection.
the presence of mononuclear cells at endothelial cells of large and small vessels in the
graft.
an immune response directed against the microvasculature.
moderate to severe microvascular destruction respond less adequately to steroid
therapy compared to patients with only mild destruction of the microvascular
endothelium.
extensive leukocyte infiltration into the peritubular capillaries.
Circulating leukocytes target HLA molecules expressed on the PTC, which results into
cellular rejection. In addition, the HLA molecules can also be targeted by donor-specific
antibodies, leading to local complement activation and humoral rejection.
C4d deposition in PTC has been associated with steroid resistance.
prognostic biomarkers for steroid resistant rejections:
Biomarkers for molecular and cellular mechanisms involved in graft survival and
medication responsiveness could provide complementary parameters.
Immune biomarkers:
Resistance to GCs has been associated with increased expression of cytotoxic T
lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage.
Cytotoxic T lymphocytes and NK cells:
the presence of T lymphocytes. The extent of CD8+ T cells infiltration within the allograft
was correlated with response to AR treatment with GCs.
Furthermore, relatively high FasL mRNA expression and dense granulysin staining renal
allograft biopsies, as well as low FoxP3 expression in urinary sediments.
B lymphocytes. The extent of B cell infiltration within the renal allograft was shown to
discriminate between steroid resistant and steroid response AR episodes. Patients with
steroid-refractory AR expressed increased intragraft levels of the B cell marker CD20.
immunostainings for CD20 revealed significant differences in the level of B cell
infiltration during AR, which correlated with response to steroid therapy and long-term
graft outcome.
Macrophages:
Macrophages derived from the transplant recipient are an important aspect of the
immune infiltrate during Ar. Macrophage infiltration within the kidney transplant has been
related with response to GC treatment.
challenges for biomarker identification:
in clinical study showed that a combination of T cell activation markers CD25:CD3ε ratio
and lymphocyte activation gene-3 (LAG-3) offers an improved prognostic value for
assessing steroid response, compared to conventional clinical parameters and
histopathologic assessment.
Non-immunological biomarkers:
A relatively novel finding is the link between zinc regulation and resistance to anti-
rejection treatment with steroids.
Relatively high intragraft expression of metallothioneins (MT) and tissue inhibitor of
metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with
steroid resistances.
Combination of immune- and non-immune biomarkers:
Combination of biomarkers in a multivariate prediction model could enhance sensitivity
and specificity, and facilitate risk assessment of steroid resistance in patients suffering
from AR.
Glucocorticoid receptor expression:
the anti-inflammatory and immunosuppressive actions of GCs are mediated by the
ligand-dependent GR. Consequently, differences in response to treatment with GCs may
be explained by variations in GR expression. Decreased GR expression has been
implicated as a cause of steroid resistance in a wide variety of diseases, including
nephrotic syndrome, acute lymphoblastic leukemia, and asthma. The observed
differences in GR expression between responders and no responders might be a
reflection of varying levels of GR autoregulation.
differences in treatment response may also be explained by genetic variability. Mutations
in the GR gene (NR3C1, nuclear receptor subfamily 3, group C, member 1) can affect
the functionality of the GR and result in steroid resistance.
Clinical implications:
steroid resistance is a complex and multifactorial condition, in which both immunological
and non-immunological factors can be involved.
Investigations of immune-related biomarkers revealed that both T cells and macrophages
play an important role in the response to steroid therapy.
Combined, these findings indicate that steroid resistance resides in specific cell
populations.
This may guide the therapeutic approaches for treatment of steroid-refractory AR
episodes. Furthermore, Zinc regulation may play a role in the response to steroid
therapy during AR.
Kidney transplant recipients who express high intragraft levels of MT and TIMP1 during
AR might benefit from extra zinc intake for optimal GC signaling.
multivariate prediction model, containing biomarkers related to different aspects of GC
signaling, offers a superior prognostic value for assessing steroid response compared to
conventional clinical parameters and histopathologic assessment, and to single
biomarkers.
Such a multivariate approach could identify patients with insufficient response to anti-
rejection treatment with GCs, who would benefit from immediate ATG treatment.
Future perspectives:
Validations of the prognostic value of biomarkers.
MicroRNA expression as a novel biomarker for response to steroid.
Non-invasive methods for monitoring of graft outcome.
Conclusion:
Resistance to steroid therapy is a complex and multifactorial condition, in which both
immunological and non-immunological factors can be involved.
Zinc regulation and drug metabolism may play a role in the response to steroid therapy
during acute renal allograft rejection. Therefore, kidney transplant recipients may benefit
from additional zinc intake to optimize GC signaling.
A multivariate prediction model, containing biomarkers related to different aspects of GC
signaling, offers the best prognostic value for assessing steroid response.
Adoption of different biomarker can help in prediction of early resistance to Gcs.
So avoidance of delay of initiation of ATG and salvage of graft.
§ the majority of acute AR episodes can be adequately treated with
§glucocorticoid therapy, 25 to 30% of the rejection episode cannot be reversed with glucocorticoids alone.
§ Prediction of steroid resistance
o could prevent unnecessary exposure to high-dose cor ticosteroid
otherapy and
o avoid the development and progression of irreversible nephron.
§ acute rejection (AR) is a main risk factor for adverse graft outcome. AR is primarily a cellular immune which generally occurs during the early post-transplant period, with the highest risk in the first 3 months.
Impact of acute rejection on graft outcome
The introduction of immunosuppressive medications has reduced the incidence of AR from over 80% to below 15% .
the short-term survival of kidney grafts has substantially improved, with one-year graft survival rates in excess of 90% in current daily practice but the long-term graft outcome improved only marginally over the past two decades. Even after the introduction of immunosuppressive medication, AR
continues to be a primary cause of renal allograft failure.
the occurrence of AR correlates with a significant reduction in long-term allograft survival.
Chronic allograft nephropathy is the most prevalent cause of chronic allograft failure after the first post-transplant year .
Analyses of factors related to the development of IFTA revealed AR as one of the primary risk factors
Various parameters of AR determine the level of risk for adverse
graft outcome including
§ the timing,( Risk increases as the time between engraftment and occurrence of AR increases)
§ recurrence,( repeated AR episodes are at greater risk of adverse graft outcome)
§ severity, ( vascular rejection (Banff grade II) have a higher risk compared to tubulointerstitial rejection (Banff grade I)
§ therapy sensitivity of the AR episode .(rejection episodes unresponsive to AR treatment have been associated with increased risk of allograft failure )
Treatment of acute renal allograft rejection
Synthetic corticosteroids
The first time to use of immunosuppressive drugs for the treatment of acute RA was in 1960
Nowadays, intravenous pulse therapy with high-dose methylprednisolone has become the first-line therapy for AR in most medical centers.
ATG therapy causes depletion of T cells through various mechanisms, including
§ antibody- and complement dependent lysis
§ the induction of apoptosis .
ATG is an effective treatment of AR with high graft survival rates .\
ATG has complications, such as leukopenia, cytokine release syndrome, and viral infections [
Due to the risk of complications ATG is mainly used for the treatment of
§ steroid-resistant AR
§ recurrent AR.
The murine derived Muromonab- CD3 (OKT3) is amonoclonal antibody based treatment directed against the CD3 molecule,
Due to its lower efficacy and higher incidence of side effects compared to ATG treatment, OKT3 has been with drawn from the market and is no longer in clinical use.
Immunoregulatory effects of corticosteroids
The therapeutic effects of synthetic GCs for the treatment of acute renal allograft rejection are attributed to their anti-inflammatory and immunosuppressive effects.
These protective effects on the allograft are mainly obtained through direct and indirect regulation of immune-related gene transcription. GCs regulate approximately 20% of all genes expressed in leukocytes.
The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes. Besides the downregulation of pro-inflammatory genes, GCs increase the expression of anti-inflammatory cytokines and transcription mediators
Steroid resistance
The majority of acute renal allograft rejection episodes can be adequately treated with high-dose corticosteroids. However, in approximately 25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone.
In steroid resistance, the patient requires more rigorous immunotherapy to reverse the AR episode.
Renal allograft recipients with steroid-refractory rejection are generally treated with ATG, which results in a salvage rate of 70 to 90% .
An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids
within 14 days after the start of the steroid therapy . At that point, ATG treatment is generally required.
The first few days after the start of the steroid treatment are crucial.
Analysis of creatinine courses of steroid-resistant and steroid-responsive cases revealed that
the minimal time period for assessment of the response to steroids is five days after initiation of the pulse therapy.
Changes in serumcreatinine levels were similar between patients with steroid responsive
and steroid resistant AR until day 5, at which time the responders showed a significant decrease in serum creatinine, while the creatinine level of non-responders remained high. This 5-day period is also the average time delay used by clinicians before considering a rejection as
being steroid resistant .Incomplete restoration of graft function in steroid resistant rejectionmay lead to progression of chronic damage to the graft and has a detrimental effect on graft outcome
Assessment of risk for steroid resistance
Clinical and pathologic indicators of steroid resistant rejection
Several parameters have been associated with response to steroid treatment.
§ Acute vascular rejection
§ the presence of mononuclear cells at endothelial cells of large and small vessels
§ the presence of an immune response directed against the microvasculature.
§ Patients with moderate to severe microvascular destruction respond less adequately to steroid therapy
§ more extensive leukocyte infiltration into the peritubular capillaries (PTC).
§ C4d deposition in PTC has been associated with steroid resistance.
§ increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage signatures . steroid resistance may reside in specific lymphocyte populations, with activat ed T cell populations as the prime candidate.
§ no single biomarker has been able to predict the response to steroid treatment with both high sensitivity and high specificity
§ Decreased GR (glucocorticoid receptor )expression has been implicated as a cause of steroid resistance in a wide variety of diseases.
Clinical implications
steroid resistance is a complex and multifactorial condition, in which both immunological
and non-immunological factors can be involved. both T cells and macrophages play an important role in the response to steroid therapy.
Zinc regulation may play a role in the response to steroid therapy during AR. Kidney transplant recipients who express high intra graft levels of MT and TIMP1 during AR might benefit from extra zinc intake for optimal GC signaling.
Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection
Introduction
Renal transplant has been a successful treatment improving the life expectancy of patients with ESRD.
40% of transplants still fail within the first 10 years.
Acute rejection is the major reason for the vast majority of graft dysfunction.
AR is diagnosed using both clinical and histological parameters.
Clinical parameters range from asymptomatic to significant creatinine rise and proteinuria.
No clinical biomarkers for AR.
Response to antirejection treatment is difficult to measure.
AR impact on graft outcomes
Immunosuppressive medications have improved AR from over 80% in the 1960 to 15% in current time.
Long-term graft outcomes still poor.
Graft loss 50% for deceased donor and 30% living donor 10 years post-transplant.
AR episodes associated with reduced graft survival.
AR is the main risk factor for renal interstitial fibrosis and tubular atrophy (IFTA).
More frequent episodes of AR cause worse graft outcomes.
AR resistant to treatment increases risk of graft failure.
AR treatment
Current immunosuppressive medication work mainly by supressing T cell function and activation.
Synthetic corticosteroids
Iv pulse therapy with high dose methylprednisolone is first line treatment for AR.
Work by regulating gene transcription in leukocytes
Suppresses inflammatory genes activated during AR
Increase express of anti-inflammatory genes
Effects on intracellular glucocorticoid receptor, especially GR-alpha
Polyclonal and monoclonal antibodies
ATG is serum derived polyclonal antibodies from horses or rabbits immunized with human lymphocytes.
Depletes circulating T cells and other white cells
Induces apoptosis, complement and antibody dependent cell death
Effective treatment for AR with profound complications and infection risk
Used for steroid resistant AR and recurrent AR
OKT3 (murine derived muromonab-cd3) a monoclonal antibody against CD3
No longer on the market due to efficacy and many side effects
Steroid resistance
25 to 30% of AR is steroid resistant.
Steroid resistance is failure for creatinine to return to within 120% of baseline value within 14 days of steroid pulse therapy.
Response should be seen 5 days after steroid pulse.
ATG is used to treat renal steroid resistant AR with 70 to90% success.
Assessment of risk for steroid resistance
Factors associated with steroid resistance
Acute vascular rejection and presence of mononuclear cells at endothelial cells of vessels
Immune response against microvasculature
Extensive leukocyte infiltration in peritubular capillaries.
C4d deposition in PTC
Prognostic biomarkers for steroid resistance
Poor prognostic markers
Increased CD8+ and NK cell infiltration
Increased mRNA expression levels of CD8+ and NK
low FoxP3 expression in urinary sediments
Increased graft infiltration with CD20 B lymphocytes and immunoglobulin producing cells
Increased graft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1)
Decreased glucocorticoid receptor expression
Conclusion
There are multiple factors associated with glucocorticoid resistance both immunological and no-immunological factors . Current no commercially available biomarkers for predicting this resistance. However the level cellular infiltration and type of cells on the biopsy can give us practical clues on who is likely to have glucocorticoid resistance.
Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection
Acute rejection is associated with poor graft outcome in form of chronic graft dysfunction and graft loss. Around 25-30% of rejection is not responding to glucocorticoid treatment and has been associated with higher risk of graft failure. ATG is used for treatment of steroid-resistant and recurrent acute rejection episodes.
Steroids regulate 20% of genes expressed in leukocytes, inhibit inflammatory genes activated in rejection eg genes encoding cytokines, chemokines, adhesion molecules and inflammatory enzymes .Also, steroids inhibit leukocyte migration, result in induction of cell death in lymphocytes and have effect on growth and lineage commitment of T cells. They act on glucocorticoid receptor(GR), activating it through removing GR inhibitory complex and enter nucleus after dimerization, where they act on glucocorticoid response elements and lead to increase in anti-inflammatory genes, decrease in pro-inflammatory genes, zinc dependent recruitment of HDAC-2, inhibiting active chromatin leading to decrease in activation of pro-inflammatory genes and decreased cell proliferation by inhibiting MAP kinase. So altered molecular mechanisms of GR signaling can lead to steroid resistance.
Steroid resistant rejection is considered if serum creatinine does not fall to less than 120% of the baseline within 14 days following pulse steroid therapy. The usual period to assess steroid response is 5 days after initiation of pulse steroid treatment. ATG treatment is usually required at this time with 70-90% success rate in reversing rejection. Additional zinc is useful in glucocorticoid signaling.
Steroid resistance is manifested in specific cell populations. Clinical and pathological indicators of steroid resistance include acute vascular rejection, mononuclear cells at endothelial cells of small and large vessels in graft, immune response directed against vasculature, more extensive leukocyte infiltration and C4d deposition in peritubular capillaries. Immunological biomarkers of steroid resistance include increased cytotoxic T lymphocyte – NK cell signature ;increased FasL mRNA, decreased FoxP3 in urine and increased dense granulation stain in biopsy, B lymphocyte signature ;increased CD20 and B lymphocyte associated immunoglobulin in the graft, and intra glomerular and interstitial macrophage signature (CD68) & increased CD25-CD3e ratio and LAG-3 (lymphocyte activationgene-3). Non-immune biomarkers include removal of zinc ion by increased intragraft metallothioneins and TIMP-1 (tissue inhibitor of metalloproteinase-1) and F2R (coagulation factor II receptor). Decreased GR expression has been associated with reduced ratio of GR alpha/ GR beta.
Steroid resistance has multiple factors. T cells & macrophages play important role in steroid response to the rejection.
Impact of study on clinical practice
Kidney biopsy with DSA assay should be undertaken as early as possible when rejection is suspected. In case of no response to steroids within 5 days, possibility of steroid resistance is high and so ATG administration should be considered. Treatment of AMR with IVIG/ plasmapheresis.
Article Summary :
Despite the success of renal transplantation, approximately 40% of renal allografts fail within thefirst 10 years, Even after the introduction of immunosuppressive medication, AR continues to be a primary cause of renal allograft failure. Approximately 10% of all graft losses are directly caused by acute renal allograft rejection. In addition, the occurrence of AR correlates with a significant reduction in long-term allograft survival . AR is also correlatedwith the development of chronic allograft failure. Renal interstitial fibrosis and tubular atrophy (IFTA)—which was formerly known as chronic allograft nephropathy (CAN)—is the most prevalent cause of chronic allograft failure after the
first post-transplant year .
Various parameters of AR determine the level of risk for adverse graft outcome including the timing, recurrence, severity, and therapy sensitivity of the AR episode .
Treatment of acute renal allograft rejection :
1]. Synthetic corticosteroids
The first report on the use of immunosuppressive drugs for the treatment of acute renal allograft rejection appeared in 1960 , synthetic glucocorticoids (GCs) are used for both the prevention and treatment of AR . Nowadays, intravenous pulse therapy with high-dose methylprednisolone has become the first-line therapy for AR in most medical centers
2] ATG
ATG
therapy causes depletion of circulating T cells and other leukocytes]. ATG is an effective
treatment of AR with high graft survival rates . However, ATG can induce complications, such as leukopenia, cytokine release syndrome, and viral infections . Due to the risk of complications, ATG is mainly used for the treatment of steroid-resistant AR and recurrent
AR.
Immunoregulatory effects of corticosteroids
The therapeutic effects of synthetic GCs for the treatment of acute allograft rejection are attributed to their anti-inflammatory and immunosuppressive effects. These protective effects on the allograft are mainly obtained through direct and indirect regulation of
immune-related gene transcription. GCs regulate approximately 20% of all genes expressed in leukocytes
The major action of GCs is the:
1] suppression of inflammatory genes that are activated during AR, including
genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory
enzymes ].
2]GCs increase the expression of antiinflammatory cytokines and transcription mediators
3] prevention of leukocyte migration,
4]induction of cell death in lymphocytes
5] effects on the growth and lineage commitment of T cells
Corticosteroid signaling & steroid resistance
The actions of GCs are mediated by the intracellular glucocorticoid receptor (GR) which is ubiquitously expressed in most human cells . The signaling pathways of the GC-GR complex inhibit the transcription of pro-inflammatory molecules, including cytokines,
chemokines, adhesion molecules, inflammatory enzymes, and receptors. Alterations in the molecular mechanisms of GR signaling may lead to steroid resistance.
Although The majority of acute renal allograft rejection episodes can be adequately
treated with high-dose corticosteroids. However, in approximately 25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone .
An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy . in fact the minimal time period for assessment of the response to steroids is five days after initiation of the pulse therapy , at which time the responders showed a significant decrease in serum creatinine, while the creatinine level of non-responders remained high.
Assessment of risk for steroid resistance
predicting resistance could prevent the unnecessary exposure to high doses of steroids and avoid progresssive irreversible nephron loss during the period of ineffective AR therapy with GC alone .
pathologic indicators of steroid resistant rejection
Several parameters have been associated with response to steroid treatment.
1] Acute vascular rejection is related to resistance to high-dose steroid therapy
2] presence of mononuclear cells at endothelial cells of large and small vessels in the graft .
3] immune response directed against the microvasculature. Patients with moderate to severe microvascular destruction respond less adequately to steroid therapy compared to patients with only mild destruction of the microvascular endothelium .
4] Extensive leukocyte infiltration into the peritubular capillaries (PTC) .
( Circulating leukocytes target HLA molecules expressed on the PTC, which results into cellular rejection.In addition, the HLA molecules can also be targeted by donor-specific
antibodies, leading to local complement activation and humoral rejection).
5] C4d deposition in PTC
Prognostic biomarkers for steroid resistant rejection
It remains difficult to predict the risk of graft loss and the response to anti-rejection treatment on basis of histopathologic assessment and clinical parameters. Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness could provide complementary parameters for assessing the risk of adverse graft outcome.
Immune biomarkers :
Expression levels of various markers in allograft histopathology , particularly those of allograft-infiltrating inflammatory cell types,were found to be informative with respect to therapy response. Resistance to GCs has been associated with increased expression of :
1/cytotoxic T lymphocyte ( extent of CD 8 + T cells infiltration in allograft )
2/ natural killer (NK) cell
3/ B lymphocyte ( high CD 20 and B lymphocytes associated Ig )
4/ macrophage ( immunostaining for CD 68 )
Challenges for biomarker identification in clinical context
Even though various immunemarkers have been proposed as prognostic biomarkers for graft outcome, clinical interpretation of these findings has proven difficult due to diversity in clinical endpoint definitions and patient cohort characteristics ( type of immnosuppression , time of AR occurence , technique of sample processing and expression analysis ) .
By attempting to overcome such diversities ,the study showed that a combination of T cell activation markers CD25:CD3ε ratio and lymphocyte activation gene-3 (LAG-3) offers an improved prognostic value for assessing steroid response, compared to conventional clinical parameters and histopathologic assessment. These two signal transduction molecules are involved in the regulation of T cells: CD25, the α- subunit of the IL-2 receptor (IL-2R), is an important regulator of T cell survival and proliferation , while the activation-induced LAG-3 is involved in the negative regulation of homeostasis and T cell function .
Non-immunological biomarkers
A relatively novel finding is the link between zinc regulation and resistance
to anti-rejection treatment with steroids. Relatively high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associatedwith steroid resistance
MT are cysteine-rich proteins involved in the regulation of zinc ions , so MT can control cellular zinc distribution such that Increased intragraft MT expression may lead to removal of zinc ions that are normally used in GC signaling . Also he binding of the activated GC-GR complex to GREs relies on two zinc finger motifs .
TIMP1 may diminish the zinc-requiring anti-inflammatory effects of the GR through regulation of the intracellular zinc concentrations .
Coagulation factor II receptor (F2R) is a regulator of numerous intracellular
signaling pathways, Differences in F2R may influence the pro- and antiinflammatory
effects of GCs .
This can be implicated clinically by giving additional Zinc intake to enhance GC signalling in kidney transplant recipients experiencing AR with the finding of high levels of intragraft expresssion of MT & TIMP1 .
Multivariate analysis of the proposed biomarkers revealed a prediction model that contains both immune (CD25:CD3ε ratio, LAG-3) and non-immune (MT-1, TIMP1,
F2R) biomarkers which offers a superior prognostic value for assessing responsiveness
to GC therapy compared to both conventional clinical and histopathologic
indicators as well as single biomarkers.
Glucocorticoid receptor expression
The anti-inflammatory and immunosuppressive actions of GCs are mediated by the ligand-dependent GR. Consequently, differences in response to treatmentwith GCsmay be explained by variations in GR expression. however , Further studies will be needed to confirm the role of the GR in transplant recipients with GC resistance .
How this article might change my practice ?
knowing that 25 – 30 % of rejecton episodes cannot be reversed with CG alone ,having a partial responce after 5 days of starting CG Rx , having histological criteria that might predict steroid non responce should all make us more aware about sterod resistance and thence to consider other therapy .
Despite the success of renal transplantation, approximately 40% of renal allografts fail within the first 10 years, and a shortage of donors hampers the number of transplants performed each year. These limitations stress the need to improve long-term graft survival and prevent adverse graft outcome. 40% of renal allograft is not functioning within the first 10 years.
acute cellular rejection diagnosed clinically or histopathologically is the major risk factor for poor allograft function.
Renal transplant recipients can still develop episodes of acute allograft rejection despite optimization of human leukocyte antigen (HLA) compatibility and application of induction therapy and maintenance immunosuppression. Several therapeutic options are available
for the reversal of AR episodes.
Treatment of acute renal allograft rejection
Synthetic corticosteroids high doses of oral prednisone was found to potentially induce toxic side effects, such as gastrointestinal hemorrhage and increased susceptibility to infection. To prevent these complicaions, the treatment was switched from oral prednisone to intravenous application of methylprednisolone, Nowadays, intravenous pulse therapy with high-dose methylprednisolone has become the first-line therapy for AR.
Polyclonal and monoclonal antibodies
ATG is used for the treatment of steroid-resistant AR and recurrent AR, induce complications, such as leukopenia, cytokine release syndrome, and viral infections so its uses is mainly used to SRAR &SRRR.
Immunoregulatory effects of corticosteroids The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes, and increasing the expression of anti-inflammatory cytokines and transcription mediators.
Steroid resistance Assessment PREDICTING STEROID RESISTANCE DURING BIOPSY PROTECT THE PATIENT AGAINEST HAZARDS OF STEROIDS AND GRAFT LOSS DURING TREATMENT .
Prognostic biomarkers for steroid resistant rejection
Immune biomarkers Resistance to GCs has been associated with increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage signatures.
Non-immunological biomarkers new discovery of zinc regulation and resistance to antirejection treatment with steroids. Relatively high intragraft expression of metallothioneins and tissue inhibitor of metalloproteinase-1 during acute renal allograft rejection is associated with steroid resistance.
How would this study change your practice? Identification and early diagnosis of steroid resistant acute rejection will save time for graft funcation plus protecting the patient for hazards of ccs. Novel discovery of zinc will improve the the response of ccs.
Acute rejection episode is considered steroid resistant when serum creatinine fails to return to 120% of pre-rejection baseline within 14 days after pulse steroids.
Steroid resistant rejection is a complex condition, Around 25% of recipients may have rejection episodes that are not reversed with steroids thus need more potent immunosuppression.
Prediction of steroid resistance at time of biopsy allows avoiding exposure to high dose steroids as well as Development and progression of graft damage .
Moderate to severe microvascular destruction responds less adequately to steroid therapy.
Extensive leucocyte infiltration into peritubular capillaries associated with steroid resistance.
Acute vascular rejection is related to resistance to high dose steroid.
Presence of mononuclear cells at endothelial cells of large and small vessels in the graft associated with steroid resistance.
Resistance to Steroids is associated with increased expression of cytotoxic T lymphocyte, NK cells, B lymphocytes and macrophage signatures.
There is no single biomarker that can predict the response to steroid treatment.
Combination of biomarkers could improve sensitivity, specificity and predict the response to GC in treatment of acute rejection.
Recipients with acute rejection may benefit from extra zinc intake which may have a role in response to steroid therapy; That’s a point that may affect my future practice , as well as anticipating those who may have steroid resistant rejection.
How would this study change your practice?
* Steroid resistance AR occurs after 5 days of start treatment especially if creatinine remains high after pulse steroid therapy.
* Use of zinc may help in steroid resistance .
* ATG used for treatment of steroid resistance rejection, so we can start with steroid for short period, if no response shift to ATG and when biopsy confirm ABMR so proceed to plasma exchange and IVIG with monitoring of DSAs.
* Strict examine graft biopsy for high risk steroid resistance rejection as vascular rejection, micro vascular inflammation and C4d deposition.
* Not all AR respond to steroid.
* Using of both immune and non-immune biomarkers to improve sensitivity and specificity of risk assessment of steroid resistant AR.
References:
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2. H.U.Meier Kriesche,A.O.Ojo,J.A.Hanson,D.M.Cibrik,J.D.Punch,A.B.Leichtman, et al., Increased impact of acute rejection on chronic allograft failure in recent era, Transplantation 70 (7) (2000 Oct 15) 1098–1100.
3. H.I. Feldman, R. Gayner, J.A. Berlin, D.A. Roth, R. Silibovsky, S. Kushner, et al., De- layed function reduces renal allograft survival independent of acute rejection, Nephrol. Dial. Transplant. 11 (7) (1996 Jul) 1306–1313.
4. J.E. Leggat Jr., A.O. Ojo, A.B. Leichtman, F.K. Port, R.A. Wolfe, M.N. Turenne, et al., Long-term renal allograft survival: prognostic implication of the timing of acute re- jection episodes, Transplantation 63 (9) (1997 May 15) 1268–1272.
5.B.L. Kasiske, M.A. Andany, B. Danielson, A thirty percent chronic decline in inverse serum creatinine is an excellent predictor of late renal allograft failure, Am. J. Kid- ney Dis. 39 (4) (2002 Apr) 762–768.
-Please give a summary of this article :
*Since the first successful transplantation performed in 1954 , kidney allograft transplantation has become the preferred renal replacement therapy for patients suffering from end-stage renal disease. At present, more than 36,500 kidney transplantations are performed annually in Europe and the United States.
* AR was the most important cause of kidney transplant loss. Only 40% of renal allograft recipients had a functioning graft at one
year after transplantation . The introduction of immunosuppressive medications and refinement in treatment regimens during the following decades has reduced the incidence of AR from over 80% in the 1960s to below 15% nowadays . Over the same period, the short term survival of kidney grafts has substantially improved, with one-year graft survival rates in excess of 90% in current daily practice.
* Various parameters of AR determine the level of risk for adverse graft outcome including the timing, recurrence, severity, and therapy
sensitivity of the AR episode. Risk of graft failure increases as the time between engraftment and occurrence of AR increases, and is most pronounced with late episodes.
* Treatment of acute renal allograft rejection:
– Synthetic corticosteroids .
– Polyclonal and monoclonal antibodies .
* Immunoregulatory effects of corticosteroids :
– anti-inflammatory and immunosuppressive effects.
– The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokine, adhesion molecules, and inflammatory enzymes . Besides the down-regulation of pro-inflammatory genes, GCs increase the expression of anti-inflammatory cytokines and transcription mediators.
-The major action of corticosteroids is the indirect suppression of pro-inflammatory genes that are activated during AR.
-The majority of acute renal allograft rejection episodes can be adequately treated with high-dose corticosteroids. However, in approximately 25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone . Similarly, poor or no response to steroid therapy for AR reversal also occurs in recipients of other solid organ transplants, including liver, lung and cardiacallografts .In such cases of steroid resistance, the patient requires more rigorous immunotherapy to reverse the AR episode. Renal allograft recipients with steroid-refractory rejection are generally treated with ATG, which results in a salvage rate of 70 to 90%.
*** Assessment of risk for steroid resistance:
– Clinical and pathologic indicators of steroid resistant rejection.
– Prognostic biomarkers for steroid resistant rejection : • Immune biomarkers.
• Cytotoxic T lymphocytes and NK cells.
• B lymphocytes.
• Macrophages.
• Non- immunological biomarkers.
* Glucocorticoid receptor expression:
As described in a previous section, the anti-inflammatory and immunosuppressive actions of GCs are mediated by the ligand-dependent GR.
Consequently, differences in response to treatment with GCs may be explained by variations in GR expression. Decreased GR expression has been implicated as a cause of steroid resistance in a wide variety of diseases, including nephrotic syndrome , acute lymphoblastic leukemia , and asthma.
* Clinical implications
The data discussed in this review demonstrate that steroid resistance is a complex and multifactorial condition, in which both immunological and non-immunological factors can be involved. Investigations of immune-related biomarkers revealed that both T cells and macrophages play an important role in the response to steroid therapy. Combined, these findings indicate that steroid resistance resides in specific cell populations. This may guide the therapeutic approaches for treatment of steroid-refractory AR episodes. Furthermore, Zinc regulation may play a role in the response to steroid therapy during AR. Kidney transplant recipients who express high intragraft levels of MT and TIMP1 during AR might benefit from extra zinc intake for optimal GC signaling.
References
[1] J.P. Merrill, J.E. Murray, J.H. Harrison, W.R. Guild, Landmark article Jan 28, 1956:
successful homotransplantation of the human kidney between identical twins. By John P. Merrill, Joseph E. Murray, J. Hartwell Harrison, and Warren R. Guild, JAMA 251 (19) (1984 May 18) 2566–2571.
[2] A. Lennerling, C. Loven, F.J. Dor, F. Ambagtsheer, N. Duerinckx, M. Frunza, et al., Living organ donation practices in Europe – results from an online survey, Transpl. Int.
26 (2) (2013 Feb) 145–153.
[3] J.J. Song, J.P. Guyette, S.E. Gilpin, G. Gonzalez, J.P. Vacanti, H.C. Ott, Regeneration
and experimental orthotopic transplantation of a bioengineered kidney, Nat. Med. 19 (5) (2013 May) 646–651.
[4] S. Hariharan, M.A. McBride, L.E. Bennett, E.P. Cohen, Risk factors for renal allograft
survival from older cadaver donors, Transplantation 64 (12) (1997 Dec 27)
1748–1754.
[5] G.M. Fleming, Renal replacement therapy review: past, present and future, Organogenesis 7 (1) (2011 Jan) 2–12.
[6] L.D. Cornell, R.N. Smith, R.B. Colvin, Kidney transplantation: mechanisms of rejection and acceptance, Annu. Rev. Pathol. 3 (2008) 189–220.
[7] M. Eikmans, D.L. Roelen, F.H.J. Claas, Molecular monitoring for rejection and graft
outcome in kidney transplantation, Expert Opin. Med. Diagn. 2 (12) (2008 Dec
1) 1365–1379.
Introduction:
Approximately 40% of renal allografts fail within the first 10 years, despite the success of renal transplantation. The occurrence of acute rejection is a dominant risk factor for adverse graft outcomes.
AR is a primary cellular immune response directed against mismatch donor antigens present on the cell allografts, with a higher risk in the first 3 months.
Diagnosis of AR relies on clinical parameters and histopathologic assessment of kidney biopsy samples.
However, once AR is diagnosed, it is difficult to predict the response to ant-rejection treatment based on clinical parameters and histopathologic assessment. The availability of biomarkers could provide complementary parameters for assessing the risk of adverse graft outcomes.
Impact of acute rejection on graft outcome:
Approximately 10% of all graft losses are directly caused by acute renal allograft rejection. The occurrence of AR correlates with a significant reduction in long-term allograft survival.
Parameters of AR determine the level of risk for adverse graft outcomes, including the timing, recurrence, severity, and therapy sensitivity of the AR episode [23]. The risk of graft failure increases as the time between engraftment and occurrence of AR increases,
patients with acute vascular rejection (Banff classification grade II) have a higher risk of graft failure compared to patients with (Banff classification grade I).
Treatment of acute renal allograft rejection:
1-: Synthetic corticosteroid:
used for both the prevention and treatment of AR
2-Polyclonal and monoclonal antibodies:
ATG is an effective treatment of AR with high graft survival rates
It is mainly used for the treatment of steroid-resistant AR and recurrent AR.
Immunoregulatory effects of corticosteroids:
Protective effects on the allograft are mainly obtained through direct and indirect regulation of immune-related gene transcription. GCs regulate approximately 20% of all genes expressed in leukocytes.
Inflammatory genes are indirectly regulated through interference with transcription factors and their co-activators.
The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes.
Steroid resistance:
Steroid resistance is considered when the patient serum creatinine does not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy.
5 days after the start of pulse steroid therapy is the minimal time period for assessment of response to steroid.
Steroid resistance rejection treated with ATG
Assessment of risk of steroid resistance:
The impact of steroid-refractory rejection on graft integrity stresses the need for tools to assess the response to AR treatment at an early stage.
1-Clinical and pathologic indicators of steroid-resistant rejection:
Clinical parameters and histopathologic assessment of kidney biopsies remain the gold standard for evaluating short- and long-term graft outcomes.
Parameters associated with poor response to steroid treatment (steroid resistance):
a)acute vascular rejection
b) extensive leukocyte infiltration into the peritubular capillaries (PTC)
c)deposition of c4d into the PTC endothelium, although this association could not be confirmed in a recent study.
d) Moderate to severe microvascular inflammation(extensive leukocyte infiltration of the PTC.
2-Prognostic biomarkers for steroid-resistant rejection
Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness could provide complementary parameters for assessing the risk of adverse graft outcome
a) Immune biomarkers:
Increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage signatures have been associated with steroid resistance rejection.
b) challenges for biomarker identification in a clinical context
clinical interpretation of prognostic biomarkers for graft outcome has been proven difficult
The influence of the inter-study reproducibility of biomarkers are differences in patient cohort characteristics, such as type of immune suppression and the time between transplantation and AR, as well as the techniques used for sample processing and expression analysis.
c) Non-immunological biomarkers
high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection are associated with steroid resistance.
Zinc supplementation with steroid therapy may play a role in the response to the treatment of AR
Clinical implication ;
Future perspectives:
Conclusion:
The topic help me to know more about steroid resistance AR and can be predicted from day 5
zinc supplementation help in steroid resistance AR
The occurrence of acute rejection (AR) is a dominant risk factor for adverse graft outcome. AR is primarily a cellular immune response di- rected against mismatched donor antigens present on the cells of the al- lograft ,which generally occurs during the early post-transplant period, with the highest risk in the first 3 months. Reliable and timely detection of AR episodes is important for the prevention of adverse graft outcome. Diagnosis of AR episodes relies on clinical parameters and histopathologic assessment of kidney biopsy samples.
Impact of acute rejection on graft outcome
Various parameters of AR determine the level of risk for adverse graft outcome including the timing, recurrence, severity, and therapy sensitivity of the AR episode .Risk of graft failure increases as the time between engraftment and occurrence of AR increases, and is most pronounced with late AR episodes (occurring 3 months or more after engraftment) .Similarly, patients experiencing repeated AR episodes are at greater risk of adverse graft outcome than those with no or only one episode .In addition, patients with acute vascular rejection (Banff classification grade II) have a higher risk of graft failure compared to patients with acute tubulointerstitial rejection (Banff classification grade I) .Furthermore, rejection episodes unresponsive to AR treatment have been associated with increased risk of allograft failure .
Treatment of acute renal allograft rejection
Synthetic corticosteroids
Polyclonal and monoclonal antibodies
Immunoregulatory effects of corticosteroids
The therapeutic effects of synthetic GCs for the treatment of acute renal allograft rejection are attributed to their anti-inflammatory and immunosuppressive effects. These protective effects on the allograft are mainly obtained through direct and indirect regulation of immune-related gene transcription.
Steroid resistance
Diagnosis of steroid resistance primarily relies on post- transplantation follow-up of clinical parameters reflecting renal allo- graft function. An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy .
Assessment of risk for steroid resistance
1-Clinical and pathologic indicators of steroid resistant rejection:
Acute vascular rejection is related to resistance to high-dose steroid therapy and a subsequent higher chance of graft failure [
unresponsiveness to steroid therapy has been associated with the presence of mononuclear cells at endothelial cells of large and small vessels in the graft
An- other aspect associated with steroid resistance is the presence of an immune response directed against the microvasculature. Patients with moderate to severe microvascular destruction respond less adequately to steroid therapy compared to patients with only mild destruction of the microvascular endothelium .Steroid-refractory AR has been associated with more extensive leukocyte infiltration into the peritubular capillaries (PTC) .
Prognostic biomarkers for steroid resistant rejection
Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness could provide complementary parameters for assessing the risk of adverse graft outcome.
1-Immune biomarkers
a-Cytotoxic T lymphocytes and NK cells.
b-B lymphocytes.
c-Macrophages
2-Non-immunological biomarkers
high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with steroid resistance.
This article help me now to predict steroid resistance AR after 5 days of starting treatment
Know more about GR
Use of zinc may help me in steroid resistance nephrotic syndrome cases in my practice , not only in transplantation.
2. Impact of acute rejection on graft outcome ;
3.Treatment of acute rejection ; this is done mainly by immun-osuppressive drugs which are ;
1. Synthetic corticosteriods
2.Polyclonal antibodies;
3.Monoclonal antibodies ;
4.Immuno-regulatory effects of corticosteroids ;
1.Cortico-steroid signaling ; through glucocorticoid receptor(GR) which consist of ;
5. Steroid resistance ;
6.Assessment of risk for steroid resistance ;
1.Clinical & pathologic indicators of steroid resistance rejection ; the gold standard
A) Clinical ; Cr remains high
B) Histopathology ;
2.Prognostic biomarkers for steroid resistant rejection ; this provide complementary parameters for evaluating the risk of allograft loss.
A) Immune biomarkers ; the presence of these cells in allograft biopsy are associated with steroid resistant rejection[99,100,109,120,121,129,130]
Challenges with the use of immune biomarker ;
B) Non-immunological biomarkers ;
Combination of immune & non-immune biomarkers ;
7.Clinical implication ;
8.Future prospective ;
9.Conclusion ;
This article is very helpful , I got 3 take home messages ;
Acute rejection (AR) has negative impact on graft survival. Acute rejection is primarily a cellular
immune response directed against mismatched donor antigens present on the cells of the allograft, occurs during early post transplantperiod, with the highest risk in the first 3 months. Most cases respond adequately to steroid treatment. however, 25-30% of cases are steroid resistant and can’t be recovered with steroids alone. . Diagnosis of AR episodes relies on clinical parameters and histopathologic assessment of kidney biopsy samples. Most patients who develop an AR episode are asymptomatic and present only with an increase in serum creatinine levels as an indicator of a decline in renal function .
It is still difficult to predict the responce to steroid treatment. therefore, there is a persistant need for tools to assess the responce at an early stage.
This review demonstrate that steroid resistance is a complex and multifactorial condition, in which both immunological and non-immunological factors can be involved. Investigations of immune-related biomarkers revealed that both T cells and macrophages play an important role in the response to steroid therapy. Combined, these findings indicate that steroid resistance resides in specific cell populations. Even though the biomarkers described provide a strong prognostic value for predicting a patient’s response to GC therapy, no single biomarker has been able to predict the response to steroid treatment with both high sensitivity and high specificity. This restricted power of single markers is most likely caused by the presence of multiple mechanisms underlying steroid resistance, which is reflected by the observed heterogeneity in transcriptional regulation among AR biopsy samples.
There is a link between zinc regulation and resistance to anti-rejection treatment with steroids.
I doubt we would be able to adopt detection of such sophisticated bio markers at our center and it is not cost effective at all
1 – RESUME:
Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection
The occurrence of acute rejection (AR) is a dominant risk factor for adverse graft outcome. AR is primarily a cellular immune response directed against mismatched donor antigens present on the cells of the allograft, which generally occurs during the early post-transplant period, with the highest risk in the first 3 months. Reliable and timely detection of AR episodes is important for the prevention of adverse graft outcome. Diagnosis of AR episodes relies on clinical parameters and histopathologic assessment of kidney biopsy samples. Most patients who develop an AR episode are asymptomatic and present only with an increase in serum creatinine levels as an indicator of a decline in renal function. The cause of graft dysfunction is determined based on nephropathologic criteria and histological assessment of a renal allograft biopsy – The Banff classification.
Even after the introduction of immunosuppressive medication, AR continues to be a primary cause of renal allograft failure. Nowadays, almost all transplant recipients are treated with immunosuppressive drugs to minimize the chance of AR, which act by inhibiting the activation and/or effector functions of T cells. Renal transplant recipients can still develop episodes of acute allograft rejection despite optimization of human leukocyte antigen (HLA) compatibility and application of induction therapy and maintenance immunosuppression. Several therapeutic options are available for the reversal of AR episode:
– Polyclonal and monoclonal antibodies
Anti-thymocyte globulin (ATG), which represents serum-derived polyclonal antibodies obtained from horses or rabbits immunized with human lymphocytes, as a treatment of allograft rejection. ATG therapy causes depletion of circulating T cells and other leukocytes through various mechanisms, including antibody- and complemente dependent lysis and the induction of apoptose. Due to the risk of complications, ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR.
The development of cell-hybridization techniques provided the opportunity to produce monospecific antibodies. The murine derived Muromonab-CD3 (OKT3) is a monoclonal antibody based treatment directed against the CD3 molecule, which is closely associated with the T cell receptor (TCR). OKT3 therapy modulates the TCR, resulting in the depletion of circulating T cells. OKT3 has been used as primary treatment of AR as well as a rescue therapy of steroid resistant AR episodes.
– Synthetics corticosteroids
First report on the use of immunosuppressive drugs for the treatment of acute renal allograft rejection. Pulse therapy with intravenous methylprednisolone is associated with fewer side effects than oral prednisone therapy. Nowadays, intravenous pulse therapy with high-dose methylprednisolone has become the first-line therapy for AR in most medical centers.
The therapeutic effects of synthetic glucocorticoids (GSs) for the treatment of acute renal allograft rejection are attributed to their anti-inflammatory and immunosuppressive effects. These protective effects on the allograft are mainly obtained through direct and indirect regulation of immune-related gene transcription, through of mediated by the intracellular glucocorticoid receptor (GR). GCs regulate approximately 20% of all genes expressed in leukocytes and the major action of GCs is the suppresssion of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes. The major action of corticosteroids is the indirect suppression (trans-repression) of pro-inflammatory genes that are activated during AR.
Majority of acute renal allograft rejection episodes can be adequately treated with high-dose corticosteroids. However, in approximately 25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone. Renal allograft recipients with steroid-refractory rejection are generally treated with ATG, which results in a salvage rate of 70 to 90%. An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy.
Acute vascular rejection is related to resistance to high-dose steroid therapy and a subsequent higher chance of graft failure. Steroid-refractory AR has been associated with more extensive leukocyte infiltration into the peritubular capillaries. Circulating leukocytes target HLA molecules expressed on the peritubular capillaries , which results into cellular rejection. In addition, the HLA molecules can also be targeted by donor-specific antibodies, leading to local complement activation and humoral rejection. The activation of the complement cascade leads to the formation of complement degradation factor C4d, which can covalently bind to the peritubular capillaries endothelium. C4d deposition in peritubular capillaries has been associated with steroid resistance , although this association could not be confirmed in a recent study. Indeed, expression levels of various markers, particularly those of allograft-infiltrating inflammatory cell types, were found to be informative with respect to therapy response. Analyses of AR biopsies obtained from kidney transplant recipients have provided insight into the lymphocyte populations that are associated with poor graft outcome. Resistance to GCs has been associated with increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage signatures, these being considered bioarmarkers.
The data discussed in this review demonstrate that steroid resistance is a complex and multifactorial condition, in which both immunological and non-immunological factors can be involved. Investigations of immune-related biomarkers revealed that both T cells and macrophages play an important role in the response to steroid therapy. Combined, these findings indicate that steroid resistance resides in specific cell populations. Even though the biomarkers described provide a strong prognostic value for predicting a patient’s response to GC therapy, no single biomarker has been able to predict the response to steroid treatment with both high sensitivity and high specificity. This restricted power of single markers is most likely caused by the presence of multiple mechanisms underlying steroid resistance, which is reflected by the observed heterogeneity in transcriptional regulation among AR biopsy samples.
2 – How would this study change your practice?
Corticosteroid resistance screening should be put into practice daily through a protocol of suspicion and investigation.
– I would define as suspicion: the unexplained increase in creatinine (= not related to factors such as immunosuppressant concentration and vascular events) + increase in biomarkers (even knowing that in the single biomarker it has been able to predict the response to steroid treatment with both high sensitivity and high specificity.)
– It would lead to early investigation: biopsy, for the diagnosis of infiltrates: NK cells, Cytotoxic T lymphocytes, B lymphocytes, Macrophages.
Please give a summary of this article :
How would this study change your practice?
Please give a summary of this article
# Approximately 40% of renal allografts fail within the first 10 years, these limitations stress the need to improve long term graft survival and prevent adverse graft outcome.
# Acute rejection is primarily a cellular
immune response directed against mismatched donor antigens present on the cells of the allograft, occurs during early post transplantperiod, with the highest risk in the first 3 months.
# 25 to 30% of the acute rejection episode cannot be reversed with glucocorticoids alone.
# Prediction of steroid resistance could prevent unnecessary exposure to high dose corticosteroid therapy and avoid the development and progression of irreversible nephron.
# Most patients who develope an AR episode are asymptomatic and present only with an increase in serum creatinine levels as an indicator of a decline in renal function .
# Diagnosis of AR episodes relies on clinical parameters and histopathologic assessment of kidney biopsy samples .
# The Banff classification is used to identify and designate the severity of rejection episodes on the basis of the site and degree of inflammation in the transplanted kidney, but it is difficult to predict the response to antirejection treatment.
#This study provides an overview of biomarkers of steroid resistant rejection
in kidney transplantation.
# Various parameters of AR determine the level of risk for adverse graft outcome including the timing, recurrence, severity, and therapy sensitivity of the AR episode.
# Treatment of acute renal allograft rejection:
* Immunosuppressive medication is a cornerstone in the prevention of transplant rejection, it act by inhibiting the activation and/or effector functions of T cells.
* Renal transplant recipients can still develop episodes of acute allograft rejection despite optimization of human leukocyte antigen (HLA) compatibility and application of induction therapy and maintenance immunosuppression.
#Several therapeutic options are available for the reversal of AR episodes.
# Synthetic corticosteroids
for both prevention and treatment of AR
it showed an essentially complete recovery of their renal function.
* High dose pulse therapy with intravenous methylprednisolone is associated with fewer side effects than oral prednisone therapy, become the first line therapy for AR in most medical centers.
# Polyclonal and monoclonal antibodies
* Anti-thymocyte globulin (ATG)
serum derived polyclonal antibodies obtained from horses or rabbits immunized with human lymphocytes
* Causes depletion of circulating T cells and other leukocytes through various mechanisms, including antibody- and complement dependent lysis and the induction of apoptosis, is an effective
treatment of AR with high graft survival rates
* ATG is mainly used for the treatment of steroid resistant AR and recurrent AR.
* S/E leukopenia, cytokine release syndrome, and viral infections.
# The murinederived Muromonab-CD3 (OKT3) is a monoclonal antibody based treatment directed against the CD3 molecule, which is closely associated
with the T cell receptor (TCR)
* used in treatment of AR & steroid resistant AR.
* S/E lower efficacy higher incidence of side effects compared to ATG treatment, has been withdrawn from the market.
# Immunoregulatory effects of corticosteroids:
* The therapeutic effects for the treatment of AR are due to their anti inflammatory and immunosuppressive effects, through direct and indirect regulation of immune related gene transcription (genes for cytokines, chemokines, adhesion molecules, and in-
flammatory enzymes).
* GCs increase the expression of anti inflammatory cytokines and transcription mediators.
* Prevention of leukocyte migration, induction of cell death in lymphocytes, and effects on the growth and lineage commitment of T cells.
# Steroid resistance
* Poor or no response to steroid therapy for AR reversal also occurs in recipients of other solid organ transplants, including liver, lung and cardiac allografts
* In such cases of steroid resistance, the patient requires more rigorous immunotherapy to reverse the AR episode.
* Recipients with steroid refractory rejection are generally treated with ATG, which results in a salvage rate of 70 to 90% of the cases.
# Diagnosis of steroid resistance AR
* Depend on post transplantation follow up of clinical parameters reflecting renal allograft function.
* patient’s serum creatinine levels do not return to within 120% of the pre rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy .
* ATG treatment is generally required in the first few days after the start of the steroid treatment are crucial.
* The minimal time for assessment of the response to steroids is five days after initiation of the pulse therapy.
# Assessment of risk for steroid resistance:
* The progression of irreversible nephron loss during the steroid resistance AR could be avoided, this need for tools to assess the response to AR treatment in an early stage.
* Clinical and pathologic indicators of steroid resistant acute rejection
– Acute vascular rejection is related
to resistance to high dose steroid therapy. – Presence of mononuclear cells at endothelial cells of large and small vessels in the graft.
– Presence of an immune response directed against the microvasculature. ( Patients with moderate to severe microvascular destruction respond less adequately to steroid therapy compared to patients with only mild destruction of
the microvascular endothelium.) -Extensive leukocyte infiltration into the
peritubular capillaries.
– HLA molecules can also be targeted by DSA leading to local complement activation and humoral rejection.
– Formation C4d and deposition in PTC.
# Prognostic biomarkers for steroid resistant rejection:
* Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness could provide complementary parameters for assessing the risk of adverse graft outcome.
** Immune biomarkers
– Cytotoxic T lymphocytes and NK cells
*The first immune component linked with resistance to anti rejection treatment presence of T lymphocytes.
* The extent of CD8+ T cells infiltration within the allograft was correlated with response to AR treatment with GCs
– B lymphocytes
* Increased intragraft levels of the B cell marker CD20 and B-lymphocyte associated immunoglobulins.
– Immunostainings for CD68 revealed the presence of intraglomerular and interstitial macrophagesduring AR as prognostic markers for steroid resistance and graft outcome .
** Non-immunological biomarkers
– Novel finding relation between zinc regulation and resistance to anti rejection treatment with steroids.
– High intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during AR is associated with steroid resistance.
** Combination of immune and non immune biomarkers
– No single biomarker has been able to predict the response to steroid treatment with both high sensitivity and high specificity, so combination of both immune and non immune biomarkers give better results.
# Glucocorticoid receptor expression
* Differences in response to treatment with GCs may be explained by variations in GR expression.
* Decreased GR expression has been implicated as a cause of steroid
resistance.
* The observed differences in GR expression between responders and nonresponders might be a reflection of varying levels of GR autoregulation.
* The ratio of primary GRα and cytokine induced GRβ isoforms impact responsiveness.
* Therole of GRβ in steroid resistance remains controversial.
* In addition to GR expression levels, differences in treatment response may also be explained by genetic variability.
* Study revealed no correlation between steroidrefractory AR and the GR. Both the NR3C1 genotype distribution and
GR expression levels in the renal allograft were similar between kidney transplant recipients with response and resistance to GC treatment of AR.
# Clinical implications
– This study guide the therapeutic approaches for treatment of steroid
refractory AR episodes.
– Zinc regulation may play a role in the response to steroid therapy during AR.
– Kidney transplant recipients who express high intragraft levels of MT and
TIMP1 during AR might benefit from extra zinc intake for optimal GCsignaling.
– The presence of multiple mechanisms underlying steroid resistance probably accounts for the restricted predictive power of single markers.
– Multivariate prediction model, containing biomarkers related to different aspects of GC signaling, offers a superior
– Such a multivariate approach could identify patients with insufficient response to anti rejection treatment with GCs, who would benefit from immediate ATG treatment.
# How would this study change your practice?
– Early diagnosis of steroid resistant acute rejection is important to prevent further graft damage.
– AR need further study and methods to predicted than ordinary one that used in our practice.
– Not all AR responding to GC.
Renal biopsy and C4d should taken as soon as possible to looking for causes of rejection
– So we can start with steroid for short period if there is no response we shift to ATG , when biopsy confirm the ABMR plasma exchange and IVIG.
– Recipients with acute rejection may benefit from extra zinc intake which may have a role in response to steroid therapy
.-Acute rejection (AR) associates with the development of chronic allograft Failure and loss of a transplanted kidney.
Several therapeutic options are available for the reversal of AR episodes:
Synthetic corticosteroids
-Intravenous pulse therapy with high-dose methylprednisolone is the first-line therapy for AR in most medical centers.
Polyclonal and monoclonal antibodies
-ATG is used for the treatment of steroid-resistant AR and recurrent AR.
Immunoregulatory effects of corticosteroids(GC):
-The therapeutic effects of synthetic GCs for the treatment of acute
renal allograft rejection is attributed to their anti-inflammatory and
immunosuppressive effects.
-The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes, and increasing the expression of anti-inflammatory cytokines and transcription mediators.
Steroid resistance
-25 to 30% of the patients with AR episodes cannot be reversed with corticosteroid therapy alone.
-Renal allograft recipients with steroid-refractory rejection are generally treated with ATG, which results in a salvage rate of 70 to 90%.
– An AR episode is considered steroid-resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy.
-Incomplete restoration of graft function in steroid-resistant rejection may lead to progression of chronic damage to the graft and has a detrimental effect on graft outcome.
Assessment of risk for steroid resistance
Clinical and pathologic indicators of steroid-resistant rejection
-Acute vascular rejection is related to resistance to high-dose steroid therapy and a subsequent higher chance of graft failure.
-Steroid resistance therapy has been associated with the presence of mononuclear cells in endothelial cells of large and small vessels in the graft.
-Steroid-refractory AR has been associated with more extensive leukocyte infiltration into the peritubular capillaries.
-C4d deposition in PTC has been associated with steroid resistance.
Prognostic biomarkers for steroid-resistant rejection
-Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness could provide complementary parameters for assessing the risk of adverse graft outcomes.
-Resistance to GCs has been associated with increased expression of cytotoxic
T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage
signatures.
-Patients with steroid-refractory AR expressed increased intragraft levels of the B cell marker CD20 and B-lymphocyte-associated immunoglobulins.
– Immunostainings for CD68 revealed the presence of intraglomerular and interstitial macrophages during AR as prognostic markers for steroid resistance and graft outcome.
Non-immunological biomarkers
-There is a link between zinc regulation and resistance to anti-rejection treatment with steroids.
-High intragraft expression of metallothioneins (MT) and tissue inhibitor of
metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with steroid resistance.
-differences in response to treatment with GCs may be explained
by variations in GC-receptors expression.
Steroid role in treatment of graft rejection is modulated through the following mechanisms
· suppression of inflammatory genes
· increasing the expression of anti-inflammatory cytokines and transcription mediators
· prevention of leukocyte migration,
· induction of lymphocytes death
· effects on the growth and lineage commitment of T cells
Steroid resistance is due to immunological and non-immunological factors. Steroid resistence rejection is defined as failure of returning . this article defined Steroid resistance as failure of serum creatinine to “return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy”
Clinical and pathologic indicators of steroid resistant rejection
· Acute vascular rejection
· presence of mononuclear cells at endothelial cells of large and small vessels in the graft
· moderate to severe microvasculature destruction
· extensive leukocyte infiltration into the (PTC) which target HLA molecules
· C4d deposition in PTC
Prognostic biomarkers for steroid resistant rejection are difficult to be identified due to differences in definitions of SR,patients cohort and analysis techniques . Combination of both immune and non immune biomarkers shows some promising results.
a) Immune biomarkers
1- High expression of cytotoxic T lymphocyte & natural killer (NK) cell (relatively high biopsy FasLmRNA expression and dense granulysin staining beside lowurine FoxP3 ). T cell activation markers CD25:CD3ε ratio and lymphocyte activation gene-3 (LAG-3)
2- high B lymphocyte , B cellmarker CD20 and B-lymphocyte associated immunoglobulins
3- intra graft macrophage(CD68) and are associated with intimal arteritis and C4d deposition
b) Non-immunological biomarkers through zinc regulation : Relatively high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) in activated macrophages and tubular epithelial decrease cellular zinc ions needed for steroid signaling
this study will encourage us to persuade our local lab to adopt the use of the new biomarkers beside the histological findings in graft biosies.
Renal transplantation is the best option for patients with ESRD. From the beginning of transplantation there was a large obstacle( Acute rejection). After using if IS the incidence of AR reduced dramatically ( 80% – <15%) with improvement of 1 year survival to >90%. Inspire of these improvement in treatment graft survival, AR still the main cause of graft failure.
Treatment of AR:
GC act through suppression of inflammatory genes which activated during AR ( genes encode for cytokines, chemokine, adhesion molecules & inflammatory enzyme genes), in addition to prevention of WBC migration, inducing cell death of lymphocytes. GC action mediated through intracellular GC receptor (GR).
Large number of AR episodes can be treated with high dose of GC but 25%-30% of patients not respond to CS alone. Steroid resistant AR defined as failure of creatinine to return to 120% of pre transplant base line after 14 days of steroid treatment.
Predictors of CS restraint AR:
(a) clinical & pathological :
(b) immune biomarkers:
(c) non immune biomarkers:
using of both immune & non immune markers to improve sensitivity & specificity of risk assessment of steroid resistant AR.
Road o HLA antibody evaluation: MFI
As the technique for detection of HLA antibodies has developed tremendously over the years from CDC assay to flow cytometry with implementation of cytometric cross match that involved the simultanous and independent assessment of both T and B cell crossmatches, to the ultimate microparticle technology. This development significantly improved the sensitivity for detection and characterization of various types of HLA antibodies.Nevertheless,this sensitive technique was not flawless, and the detected antibodies were desputably interpreted in relation to allograft outcome.
This article tried to address the different aspect of the technique and the significance of the detected antibodies with recommendation and roadmap to follow.
The microparticle technology became the surrogate lymphocytes targets,as it’s coated with class I and Il molecules. SAB assay is semiquantitative test used to assess antibody specificity.
The major contention related to SAB revolved around results reported as a numerical value referred to as mean flourescent intensity MFI.
Concerns about MFI:
1) It never intended to quantify HLA antibodies.,nor was Luminex approved as a quantitative assay.
2) MFI values reflect a given bead relative fluorescence without reference to a standered.,nevertheless, MFI was consistently used as semiquantitative assessment of antibody strength.
3)Limitations of use of MFI:
a)Threshold for positive or negative MFI ,too low false positive may preclude the patients,or too high would increase the risk of having AMR.
b) controversially, some patients transplanted against extremely low DSAs titer (100 MFI).experienced poor graft survival, in contrast, patients with (10000 MFI) had negative cross match and excellent graft outcome.
c)SAB assay is sensitive to technologist dependent action.
d)MFI value might be affected by antibody dependent complement activation,Complement split products covalent bind toantigen_antibody complexes on the beads and block binding sites for secondary reporter antibodies.
e)The presence of IgM HLA antibodies will compete and prevent the binding of IgG HLA antibodies, resultant in misleading lower MFI value associated with adverse allograft prognosis.
f)false positive MFI can occur from binding of antibodies to misfolded HLA protein, called denatured antigens,where reactivity is attributed to antibody binding of cryptic epitop,which is under normal condition ,considered as antibody unaccessible.This phenomena might be explaining why some patients with high MFI DSAs were not associated with poor graft outcome.
G) Significance of antibodies against denatured HLA antigens are yet to be addressed.
CREGs ,Epitops and Eplets:
A serologic phenomina of multiple unique HLA antigens that reacted with a single antibody
Conformation,an integral component to antibody pathogenicity:
Specific eplets or even a single amino acid difference in the epitops of different HAL antigens can change the reactivity of the HAL antigen and the potential HLA DSAs response.
HLA antigen and DSAs pathgenesity;
It’s crucial to notice that microparticles In SAB assay are coated with an amount of antigen designed to detect low level of antibodies,not to mimic the quantity of HLA antigens on lymphocytes or tissues.Therefor Invitro DSAs binding may not be the same invivo due to different concentration of HLA antigen.
Nevertheless HLA antigen is increasing with inflammation and HLA antigen may be susceptible to DSAs. Therefore it was reported that the most common de novo DSAs post transplant are those against HLA_DQ antigen,,despite low expression of DQ loci.
In vitro DSAs with low MFI could be due to low concentration of the DSAs,that spread over many HLA antigens sharing public epitops ,non of them are adequate to produce flourescent signal detected,in comparison these DSAs can combine in vivo to HLA antigen could be a target to same antibodies..
Importantly, DSAs pathogenecity can’t be assessed by MFI level.
Assessing Pathogenesity of DSAs:
Complement fixing is an important tool to assess the pathogenecity of DSAs,C1q assay is the most common tests,IgG 1 and IgG 3 both are Complement fixing and can be the culprit for AMR.however it’s debatable,as in vitro Complement fixing might not be happening in vivo as well.
Furthermore ,non complement fixing AMR, but Antibody dependent cellular cytotoxicity through Natural killer cells.
In conclusion ,each patient is different, and multidisciplinary team to assess histocompatibity for each patient.
The acute renal graft rejection is one of the main causes of graft loss and outcome. In 1960s , about 40 percent patients who had kidney transplant would survive by end of first year post transplantation. with newer immunosuppressive drugs and regimens the graft survival has increased and the chances of acute rejection have decreased . Currently it is around 15%. Banff classification is used to identify severity of rejection on the basis of site and degree of inflammation.
Treatment of acute renal allograft rejection.
Synthetic Corticosteroids
Initially oral prednisolone was used which had significant side effects like GI side effects. Later it was changed to IV methyprednisolone . Now a days the pulse therapy with IV methyprednisolone has become first line treatment of acute rejection in most centres.
Polyclonal antibodies
ATG is very effective treatment of Acute rejection and improves graft survival , However there can be complications like infections , leukopenia and cytokines storm. It can be used for recurrent or steroid resistant Acute rejection. OKT3 is mono clonal antibody directed against T cells receptor and depletes circulating T cells. I t can be used in primary and steroid resistant AR. due to less efficacy and more side effects it has been withdrawn from market.
Mechanism of action of steroids
Increase the transcription of transcription mediators and anti inflammatory cytokines and also regulate genes expressed in leukocytes. They have anti inflammatory effects and suppress genes activate during AR including inflammatory enzymes, chemokines and adhesion molecules
Steroid resistance
About 20-30 percent patients will show steroid resistance and it can be diagnosed by following the clinical parameters. AR episode is labelled as steroid resistant when serum creatinine level do not return to 120% of baseline pre rejection levels after pulse therapy with steroids. Histology in these cases shows extensive leukocyte infiltrate in peritubular capillaries.c4d deposition is also associate with steroid resistance.
Steroid resistant rejection is treated with ATG usually.
How would this change my practice.
Acute rejection is significant entity and is usually multifactorial . Renal biopsy should be considered early to diagnose and assess severity of rejection. If these is no response to steroids then ATG must be given . DSA should be monitored . For AMR IVIG and plasamphresis must be given. Drug metabolism and zinc regulation have a role in response to steroid therapy.
Summary;
In the case of acute rejection, which is most common in the early post-transplant period, it is linked with poor graft prognosis, manifested as chronic graft malfunction and graft loss, among other manifestations. Only 25-30 per cent of rejects responds well to glucocorticoid therapy alone and hence become steroid-resistant. This is linked with an increased risk of graft failure in the long term. ATG is used to treat acute rejection that is resistant to steroid therapy and that has recurred.
When the serum creatinine does not reduce to less than 120 per cent of the baseline level after 14 days of receiving pulse steroid treatment, it is termed to be resistant to steroids (steroids resistant rejection). The standard time span for evaluating steroid response is 5 days following the start of pulse steroid therapy. Usually, ATG therapy is essential at this point in time (which has a 70-90 per cent success rate in reversing rejection). Zinc supplementation is beneficial in the regulation of glucocorticoid signalling.
Perspectives for the future
It is necessary to conduct validation and verification studies on the prognostic significance of suggested biomarkers.
Before these models may be used in clinical practice, prospective investigations are required.
The expression of microRNA transcripts is a biomarker that is still in its infancy.
MicroRNA expression patterns in graft biopsies may be used to identify new predictive biomarkers for the fate of AR, according to the researchers.
The identification of non-invasive molecular markers in blood and urine may allow for the early diagnosis of graft malfunction and the prompt implementation of corrective measures.
The response to high-dose GC for AR therapy is correlated with the expression level and features of T cells and macrophages penetrating into the allograft, according to the findings.
This indicates that steroid resistance is restricted to certain cell types and is not a characteristic of all lymphocytes, as previously thought.
AR is characterized by altered zinc regulation and drug metabolism that influence steroid response.
Increased zinc consumption may help to improve GC signalling and assist transplant patients, according to research.
The use of a multivariate prediction model in clinical practice may aid in the more accurate evaluation of steroid resistance as well as the individualization of anti-rejection treatment.
What changes do you think this research will bring to your practice?
If there is no ideal response to steroids after 5 days, ATG should be investigated.
Treatment as soon as possible will stop the progression of the disease.
an episode of acute rejection is a period of uncertainty and is like to cause anxiety in ktrs and thier carers.
the occurrence of acute rejection (AR) is a dominant risk factor for adverse graft outcome. in the 1960s, AR was the most important cause of kidney transplant loss. Only 40% of renal allograft recipients had a functioning graft at one year after transplantation .The introduction of immunosuppressive medications and refinement in treatment regimens during the following decades has reduced the incidence of AR from over 80% in the 1960s to below 15% nowadays .
Tretamnt of renal allograft rejection
A-synthettic corticostreoids,
Treatment of AR with high doses of oral prednisone was found to po- tentially induce toxic side effects, such as gastrointestinal hemorrhage and increased susceptibility to infection. To prevent these complica- tions, the treatment was switched from oral prednisone to intravenous application of methylprednisolone during the early 1970s .
How steroid works?
1- regulate approximately 20% of all genes expressed in leukocytes .
2 -suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and in- flammatory enzymes .
3-increase the expression of anti- inflammatory cytokines and transcription mediators .
why some AR episodes dosent repond to steroids, or partially repons (steroid resitstant)?
1-25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone.
2- An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy .
3- Several parameters have been associated with response to steroid treatment.
4-Acute vascular rejection is related to resistance to high-dose steroid therapy and a subsequent higher chance of graft failure .
5-Steroid-refractory AR has been associated with more extensive leukocyte infiltration into the peritubular capillaries (PTC) .
6-C4d deposition in PTC has been associated with steroid resistance .
7-The extent of CD8+ T cells infiltration within the allograft was correlated with response to AR treatment with GCs .
8-Patients with steroid-refractory AR expressed in- creased intragraft levels of the B cell marker CD20 and B-lymphocyte as- sociated immunoglobulins .
9-Macrophage infiltration within the kidney transplant has been related with response to GC therapy .
10-Relatively high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is as- sociated with steroid resistance .
B-polyclonal and monolclonal antibodies,
ATG is an effective treatment of AR with high graft survival rates . However, ATG can induce complications, such as leukopenia, cytokine release syndrome, and viral infections . Due to the risk of complications,
ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR.
How would this study change your practice?
AR is a complex episode , and it depends on a lot of factors , wether this transplant is aliving one or cadveric. how many mismatches between the donor and the recipent .is the recipent is highyly sensitized or not .is there DSA befor transplantion or not .how far is the recipent from transplantion.
all these data should be kept in mind during rejection episode .
steroids are the corner stone of treatment of AR episodes, and judment of response can be made by the phyiscain himself keeping in mind the data mentioned befor about the recpient and the donor .and descion of switching the patient to more aggresive tetament depends mainly on histopathological findings regarding BANF classification.
*Introduction
improving long-term graft survival is the main goal of all doctors Since 40% of renal allografts fail within the first 10 years and there is shortage of donors togerher with difficulties in second transplant.
*Impact of acute rejection:
AR is a major risk factor for adverse graft outcome,
It usually occurs in the early post-transplant period, commonly in first 3months.
With advances in immunosuppssion AR remains the primary cause of renal allograft failure. Approximately 10% of all graft losses are directly caused by acute renal allograft rejection.
Early detection of AR episodes is important for the prevention of adverse graft outcome.
Diagnosis is made clinically and by histopathologic changes of kidney biopsy.
It may present just with rise in serum creatinine.
The Banff classification can detect severity of rejection episodes.
clinical and histopathologic assessment cant predict the response to ttt accurately. And we need biomarkers to provide complementary parameters for assessing the risk of adverse graft outcome.
AR episods is associated not only with a significant reduction in long-term allograft survival but also with graft loss, and chronic allograft failure. Renal interstitial fibrosis and tubular atrophy (IFTA)—which was formerly known as chronic allograft nephropathy (CAN)—is the most prevalent cause of chronic allograft failure after the first post-transplant year.
*Treatment of acute renal allograft rejection
All recipients are treated with immunosuppressive drugs to minimize the chance of AR, which act by inhibiting the activation and/or effector functions of T cells.
But acute rejection can still happen despite proper HLA matching and induction therapy and maintenance immunosuppression.
-therapeutic options for reversal of AR episodes;
1-Synthetic corticosteroids;In 1963, Starzl and his colleagues found that AR can be reversed by high doses of prednisone ,
And now intravenous pulse therapy with high-dose methylprednisolone has become the first-line therapy for AR in most medical centers.
2- Polyclonal and monoclonal antibodies;
ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR.
*Immunoregulatory effects of corticosteroids;
GCs regulate approximately 20% of all genes expressed in leukocytes
major action of GCs is the suppression of inflammatory genes that become activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and in-flammatory enzymes .
GCs also increase the expression of anti-inflammatory cytokines and transcription mediators they also suppress AR through a variety of other mechanisms, including the prevention of leukocyte migration, induction of cell death in lymphocytes, and effects on the growth and lineage commitment of T cells.
GCs actions are mediated by the intracellular glucocorticoid receptor (GR), GC-GR complex interferes with activating transcription factors, such as nuclear factor-κB (NF-κB), activator protein-1 (AP-1), and cyclic AMP-responsive element-binding (CREB), the GC-GR increases the transcription of inhibitor of κB(IκB) and MAP kinase phosphatase (MKP)-1, which inhibit NF-κB and mitogen-activated protein (MAP) kinase, respectively .
AR episode is considered steroid resistant serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after steroid therapy .
ATG treatment is generally required in steroid resistant cases with re assessment of the response to steroids in five days after initiation of the pulse therapy.
Predictors of steroid resistance
-Acute vascular rejection is related to resistance to high-dose steroid therapy.
-presence of mononuclear cells at endothelial cells of large and small vessels in the graft .
-presence of an immune response directed against the microvasculature.
-extensive leukocyte infiltration in PTC.
-C4d deposition in PTC ,although this association could not be confirmed in a recent study .
*Prognostic biomarkers for steroid resistant rejection
Immune biomarkers;
Resistance to GCs has been associated with increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage signatures.
Non-molecular biomarkers and zinc metabolism may predict rejection resistance to glucocorticoid use.Relatively high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with steroid resistance.
Decreased GR expression has been implicated as a cause of steroid resistance in a wide variety of diseases, including nephrotic syndrom.
steroid resistance is a complex and multifactorial condition,both T cells and macrophages play an important role in the response to steroid therapy
recipients with high intragraft levels of MT and TIMP1 during AR might benefit from extra zinc intake for optimal GC signaling.
*How would this study change your practice?
Renal biopsy as early as possible to detect histological features and severity of the rejection.
ATG to be considered after 5 days if no optimal response to steroids
Zinc supplements to patients during acute rejection.
DSA should be checked in rejection and PE AND IVIG FOR AMR
Mechanisms-and-risk-assessment-of-steroid-resistance-in-acute-kidney-transplant-rejection
Impact of acute rejection on the graft
AR continues to be a primary cause of renal allograft failure. 10% of all graft losses are directly caused by acute renal allograft rejection. In addition, the occurrence of AR correlates with a significant reduction in long-term allograft survival. Beside this association with risk of graft loss, AR is also correlated with the development of chronic allograft failure. Renal interstitial fibrosis and tubular atrophy (IFTA)—which was formerly known as chronic allograft nephropathy (CAN)—is the most prevalent cause of chronic allograft failure after the first post-transplant year.
Treatment of acute renal allograft rejection
– Corticosteroids: Nowadays, intravenous pulse therapy with high-dose methylprednisolone has become the first-line therapy for AR in most medical centers.
– Polyclonal and monoclonal antibodies
ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR
The murine derived Muromonab-CD3 (OKT3) is a monoclonal antibody, but due to its lower efficacy and higher incidence of side effects compared to ATG treatment, OKT3 has been withdrawn from the market and is no longer in clinical use.
Immunoregulatory effects of corticosteroids
The therapeutic effects of synthetic GCs for the treatment of acute renal allograft rejection are attributed to their anti-inflammatory and immunosuppressive effects.
The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes.
Besides the downregulation of pro-inflammatory genes, GCs increase the expression of antiinflammatory cytokines and transcription mediators.
In addition, glucocorticoid (GC) therapy can suppress AR through a variety of other mechanisms, including the prevention of leukocyte migration, induction of cell death in lymphocytes, and effects on the growth and lineage commitment of T cells.
Steroid resistance
25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone. Similarly, poor or no response to steroid therapy for AR reversal also occurs in recipients of other solid organ transplants, including liver, lung and cardiac allografts. In such cases of steroid resistance, the patient requires more rigorous immunotherapy to reverse the AR episode.
Renal allograft recipients with steroid-refractory rejection are generally treated with ATG, which results in a salvage rate of 70 to 90%.
Diagnosis of steroid resistance primarily relies on post-transplantation follow-up of clinical parameters reflecting renal allograft function. An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy. At that point, ATG treatment is generally required.
The first few days after the start of the steroid treatment are crucial. Analysis of creatinine
courses of steroid-resistant and steroid-responsive cases revealed that the minimal time period for assessment of the response to steroids is five days after initiation of the pulse therapy. Changes in serum creatinine levels were similar between patients with steroid responsive
and steroid resistant AR until day 5, at which time the responders showed a significant decrease in serum creatinine, while the creatinine level of non-responders remained high. This 5-day period is also the average time delay used by clinicians before considering a rejection as being steroid resistant. Incomplete restoration of graft function in steroid resistant rejection may lead to progression of chronic damage to the graft and has a detrimental effect on graft outcome.
Assessment of risk for steroid resistance
– Clinical and pathologic indicators of steroid resistant rejection
Acute vascular rejection is related to resistance to high-dose steroid therapy and a subsequent higher chance of graft failure.
Steroid-refractory AR has been associated with more extensive leukocyte infiltration into the peritubular capillaries (PTC). C4d deposition in PTC has been associated
with steroid resistance, although this association could not be confirmed in a recent study.
– Prognostic biomarkers for steroid resistant rejection
o Immune biomarkers
Resistance to GCs has been associated with increased expression of cytotoxic
T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage signatures. However, there are some challenges regarding detection of those biomarkers and significance in clinical practice.
o Non-immunological biomarkers
A relatively novel finding is the link between zinc regulation and resistance to anti-rejection treatment with steroids. Relatively high
intragraft expression of metallothioneins (MT) and tissue inhibitor of
metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with steroid resistance.
Coagulation factor II receptor (F2R) is a regulator of numerous intracellular signaling pathways, which include NF-κB and MAP kinase pathways
Even though the biomarkers described in the previous sections provide a strong prognostic value for predicting a patient’s response to GC therapy, no single biomarker has been able to predict the response to steroid treatment with both high sensitivity and high specificity
Clinical implications
The data discussed in this review demonstrate that steroid resistance is a complex and multifactorial condition, in which both immunological and non-immunological factors can be involved. Investigations of immune-related biomarkers revealed that both T cells and macrophages play an important role in the response to steroid therapy. Combined, these findings indicate that steroid resistance resides in specific cell populations. This may guide the therapeutic approaches for treatment of steroid-refractory AR episodes. Furthermore, Zinc regulation
may play a role in the response to steroid therapy during AR. Kidney transplant recipients who express high intra graft levels of MT and TIMP1 during AR might benefit from extra zinc intake for optimal GC signaling.
this affect my clinical practise to predict steroid resistance early at day 5 of starting IV methylprednisolone so we can arrange early for the next step to preserve the grafat function
☆Mechanisms and risk assessment of steroidresistance in acute kidneytransplant rejection:
____________
▪︎The present review provides an overview of biomarkers for the detection and/or prediction of steroid resistance in kidney transplantation.
▪︎The availability of biomarkers could provide complementary parameters for assessing the risk of adverse graft outcome.
*Introduction:
▪︎Acute rejection (AR) is primarily a cellular immune response directed against mismatched donor antigens present on the cells of the allograft, which generally occurs during the early post-transplant period, with the highest risk in the first 3 months.
*Impact of acute rejection on graft outcome:
____________
▪︎ Even after the introduction of immunosuppressive medication, AR continues to be a primary cause of renal allograft failure.
▪︎ AR is one of the risk factors for the development of renal interstitial fibrosis and tubular atrophy (IFTA) which is the most prevalent cause of chronic allograft failure after the first post-transplant year.
▪︎ Various parameters of AR determine the level of risk for adverse graft outcome including the timing, recurrence, severity, and therapy sensitivity of the AR episode.
Treatment of acute renal allograft rejection:
_______________________________________________Nowadays, almost all transplant recipients are treated with immunosuppressive drugs to minimize the chance of AR, which act by inhibiting the activation and/or effector functions of T cells.
▪︎Several therapeutic options are available for the reversal of AR episodes:
1) Synthetic corticosteroids:
Intravenous pulse therapy with high-dose methylprednisolone
2) Polyclonal and monoclonal antibodies: Anti-thymocyte globulin (ATG):
– ATG can induce leukopenia, cytokine release syndrome, and viral infections. So, is mainly used for the treatment of steroid-resistant AR and recurrent AR.
3) Murine derived Muromonab-CD3 (OKT3): due to its lower efficacy and higher incidence of side effects compared to ATG treatment, OKT3 has been withdrawn from the market and is no longer in clinical use.
* Immunoregulatory effects of corticosteroids:
_________ _________
The therapeutic effects of synthetic GCs for the treatment of acute renal allograft rejection are attributed to their anti-inflammatory and immunosuppressive effects (obtained through direct and indirect regulation of immune-related gene transcription).
The major action of Glucocorticoids(GCs):
____________________________________________
1. Suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes.
2. Down regulation of pro-inflammatory genes, GCs increase the expression of anti-inflammatory cytokines and transcription mediators.
3. Prevention of leukocyte migration.
4. Induction of cell death in lymphocytes.
5. Effects on the growth and lineage commitment of T cells
▪︎The actions of GCs are mediated by the intracellular glucocorticoid receptor (GR). After administration, GCs diffuse across the cell membrane and bind to the cytoplasmic GR and form GC-GR complex which regulates gene transcription through
direct and indirect signaling pathways.
▪︎The signaling pathways of the GC-GR complex inhibit the transcription of pro-inflammatory molecules, including cytokines, chemokines, adhesion molecules, inflammatory enzymes, and receptors.
▪︎Alterations in the molecular mechanisms of GR signaling may lead to steroid resistance.
☆Diagnosis of steroid resistance:
_________________________________
Primarily relies on posttransplantation follow-up of clinical parameters reflecting renal allograft function.
▪︎An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy. ATG treatment is generally required.
▪︎Analysis of creatinine courses of steroid-resistant and steroid-responsive cases revealed that the minimal time period for assessment of the response to steroids is five days after initiation of the pulse therapy ( An average time delay used by clinicians before considering a rejection as being steroid resistant).
Assessment of risk for steroid resistance:
____________________________________________
A) Clinical and pathologic indicators of steroid resistant rejection
▪︎At present, clinical parameters and histopathologic assessment of kidney biopsies remain the golden standard for evaluating short- and long-term graft outcome.
▪︎Unresponsiveness to steroid therapy has been associated with:
1. Presence of mononuclear cells at endothelial cells of large and small vessels in the graft
2. Presence of an immune response directed against the microvasculature.
3. Patients with moderate to severe microvascular destruction.
4. Extensive leukocyte infiltration into the peritubular capillaries (PTC)( in refractory response to steroid).
5. Circulating leukocytes target HLA molecules expressed on the PTC
6. Donor-specific antibodies
7. C4d deposition in PTC.
B)Prognostic biomarkers for steroid resistant rejection
1. Immune biomarkers: Resistance to GCs has been associated with increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage within the renal allograft.
2. Challenges for biomarker identification in clinical context: Steroid resistance may reside in activation of T cell populations as the prime candidate. However, the prognostic value of immune biomarkers is hampered by molecular heterogeneity among kidney biopsy samples with AR. This observation may be a reflection of the complexity of the mechanisms involved in response to steroid therapy.
3. Non-immunological biomarkers: Removal of zinc ions (which are normally used in GC signaling) and Coagulation factor II receptor (F2R) (Differences in F2R may influence the pro- and antiinflammatory effects of GCs)
4. Combination of immune- and non-immune biomarkers
5. Decreased Glucocorticoid receptor expression.
* Important points to consider in our practice:
___________
▪︎ Resistance to steroid therapy is a complex and multifactorial condition, in which both immunological and non-immunological factors can be involved.
▪︎ The response to high-dose corticosteroid therapy for the treatment of acute renal allograft rejection correlates with the expression level and characteristics of T cells and macrophages infiltrating into the renal allograft.
▪︎Zinc regulation and drug metabolism may play a role in the response to steroid therapy during acute renal allograft rejection. Therefore, kidney transplant recipients may benefit from additional zinc intake to optimize GC signaling.
▪︎The best prognostic value for assessing steroid response is multivariate prediction model, containing biomarkers related to different aspects of GC signaling which contributes in the clinical risk assessment of steroid resistance and helps in applying more individualized antirejection therapy
Acute graft rejection is one of the most frequent complications in the first three months of transplantation. In renal transplant patients, a biopsy is the gold standard for diagnosis and is usually asymptomatic, but preceded by progressive worsening of renal function (increasing creatinine values). Early treatment of rejection has an impact on recent and chronic graft survival.
Classic treatment has been the use of high doses of methylprednisolone. It has fewer side effects than oral prednisone. Glucocorticoid receptors are present on most leukocytes and their binding leads to suppression of gene regulation in the cell nucleus, leading to a drop in inflammatory cytokines, chemokines, adhesion molecules, and inflammatory mediators concomitant with an increase in anti-inflammatory mediators and cytokines.
Nearly one-third of patients may experience transplant rejection and resist the use of glucocorticoids. Patients who do not recover renal function after five days of pulse methylprednisolone are suggestive of resistance to this treatment, but there is a need for early diagnosis of this condition.
Biopsy is still the gold standard for diagnosing acute rejection and can help in the diagnosis of glucocorticoid resistance:
1. Acute vascular rejection
2. Mononuclear cells in the endothelium of graft vessels
3. Moderate to severe destruction of microvascular destruction
4. HLA molecules expressed in peritubular capillaries
5. C4d deposits in peritubular capillaries
Immune biomarkers can bring early results without the need for invasive tests such as biopsy. The early presence of T lymphocytes is a marker of rejection, mainly with cytotoxic action (CD8) or natural killers (CD16, CD56).
B lymphocytes (CD19 and CD20) activated and acting as deposits of immune complexes compromising the graft. The same occurs with macrophages (CD68) and circulating monocytes (CD14) associated with intimal arteritis and C4d deposits in peritubular capillaries.
Non-molecular biomarkers and zinc metabolism may suggest graft rejection resistance to glucocorticoid use. The expression of metallothioneins (MT) and tissue inhibitor metalloproteinase-1 (TIMP1) results in the inhibition of glucocorticoid-linked anti-inflammatory activities.
Decreased glucocorticoid receptors also decrease their effectiveness and should be considered in certain pathologies.
In kidney transplantation, the use of ATG is the most suitable alternative for lymphoablation. Even with the risk of leukopenia, cytokine release syndrome, and viral infections it is a superior alternative to muronomab.
The need for early diagnosis with good accuracy and low invasiveness is extremely important for the development of molecular diagnostic methods for appropriate therapies and increased graft survival.
a summary of this article
with modern immunosuppressive drug one year graft survival reach to to more than 90 percent but long term graft survival still low and more than 40 percent of transplanted patient loss or fail graft through 10 year post transplantation commonly caused by rejection .
steroid drug of great in treatment of rejection used since 1960,steroid use as oral or pulse steroid in acute treatment of rejection .according to study there is no difference between two group in form of efficacy but side effect more with oral compared to pulse steroid.
steroid consider anti inflammatory and immunosuppressive drug.
steroid resistant occur in 25 to 30 percent of patient with rejection.
Early prediction of steroid resistant of great value because:
1-avoid toxic effect of steroid .
2-to avoid irreversible graft damage.
How to assess for steroid resistant:
*Tissue biopsy ,presence of vascular involvement ,peritubular capillary C4d,presence of mononuclear cell on endothelial blood vessels wall (large or small vessel).
Depend on biomarker (immunological and non immunological).
Immunological:
*CD8+Lymphocyte infiltrate’s to graft corelated with steroid response .
*increase intragraft level of CD20 and B lymph immunoglobulin associated with steroid resistant .
*immunostaining for CD68 reveal presence of intra graft macrophage so indicator of steroid resistant and graft loss .
Non immunological :
novel finding related to Zink regulation through increase level of metallothionin (MT)or tissue inhibitor of metalloproteinase (TIMP).
so as to increase the sensitivity and specifity we need to use both immunological and non immunological.
How would this study change your practice?
steroid resistant should be assessed early in rejection to avoid unnecessary prolong course ,higher dose and repeat dose .
think about use of zinc with steroid to enhance response .
study should be continue to improved long term graft survival .
Acute rejection AR, is a risk factor for the allograft ,despite the major advances in immunosuppressive medications that has improved the first year graft survival to more than 90%. AR still reported to occur with incidence of 15 % .50 % of graft from deceased donor and 30 % of graft from living donors ,failed within 10 years. Acute rejection AR is a major risk factor for the adverse long term outcome of the renal allograft. Therefore diagnosing, treating and reversing the AR promptly is potentially improving the long term prognosis of the renal allograft.
IFTA, is the most prevalent cause of chronic allograft failure after the first year post transplantation. AR is the primary risk factor for IFTA. Although the incidence of AR has decreased significantly over the last decade, it’s negative impact on the allograft with subsequent development of IFTA has become more prominent.
Certain features of AR portend higher risk for IFTA, these include timing, recurrence,severity and therapy . Late AR (happening after 3 months post transplantation, recurrent rejections, acute vascular rejection (Banff class Ii) ,and unresponsiveness to the therapy,all linked to higher incidence of IFTA and allograft failure. AR is mainly CMR directed against mismatched donor antigen present on the cells of the allograft.
Basically treatment of acute CMR is with high dose pulse steroid ,which is working by binding to glucocorticoid receptor forming Gc_GR complex that inhibit NF_kF and prevent activation of inflammatory genes. However in 25_30 % of patients,the rejection episode is resistant to steroid therapy.
Second line therapy for steroid resistant AR is ATG which result in salvage of 70 to 90 % of cases.
Diagnosis of steroid resistant AR is dependent entirely on follow up of renal function parameters post pulse steroid therapy, steroid effect is noticed after 5 days when creatinine drops significantly. Steroid resistant is diagnosed when there is no reduction of creatinine after 5 days of starting steroid therapy. These five days are crucial for the long term adverse effect on the allograft, during which,the development and progression of nephron loss is undertreated with steroid alone . Furthermore, the patient will be exposed to the side effects of high dose corticosteroid therapy.
Henceforth, the identification of steroid resistant AR at the time of diagnosis is of prime importance to offset the two detrimental factors associated with the late diagnosis of steroid resistant AR.
Identifying the steroid resistant AR:
Acute vascular rejection
Presence of mononucleosis cells on endothelial cell surface of small and large blood vessels in the graft.
Presence of C4d in PTCs
Increased expression of cytotoxic T lymphocytes.
Natural killers
B_lymphocytes. CD20
Macrophage cells infiltration.
High intra_graft expression of metallothionien MT and tissue inhibitors of metalloproteinases.
Glucocorticoid Receptor expression level associated with steroid responsiveness.
Conclusion and take home message:
AR is an important factor linked with IFTA.
Prompt treatment will reverse the process
Identification of steroid resistant AR on time of diagnosis will reduce nephron loss,progression to IFTA and avoid unnecessarily high dose steroid.
III. Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection
Acute rejection, mostly seen in early post-transplant period, is associated with poor graft prognosis in form of chronic graft dysfunction and graft loss. 25-30% of rejection is not amenable to glucocorticoid treatment alone, hence is steroid resistant,and has been associated with higher risk of graft failure. ATG is used for treatment of steroid-resistant and recurrent acute rejection.
Steroids regulate 20% of all genes expressed in leukocytes, suppress inflammatory genes activated in rejection like genes encoding cytokines, chemokines, adhesion molecules and inflammatory enzymes. They inhibit leukocyte migration, cause induction of cell death in lymphocytes and have effect on growth and lineage commitment of T cells. Steroids act on GR (glucocorticoid receptor), activating it by removing the GR inhibitory complex and enter nucleus after dimerization, where they act on GRE (glucocorticoid response elements) and lead to increase in anti-inflammatory genes, reduction in pro-inflammatory genes, zinc dependent recruitment of HDAC-2, inhibiting active chromatin causing decrease in activation of pro-inflammatory genes as well as decreased cell proliferation during inflammatory process by inhibiting MAP kinase. So altered molecular mechanisms of GR signalling can cause steroid resistance.
Steroids resistant rejection is considered when the serum creatinine does not fall to less than 120% of the baseline within 14 days after pulse steroid therapy. The usual time period to assess steroid responsiveness is 5 days after initiation of the pulse steroid treatment. ATG treatment is usually required at this time (which has a 70-90% success rate in reversing rejection). Additional zinc intake is helpful in glucocorticoid signaling.
Steroid resistance is present in specific cell populations. Clinical and pathological parameters of steroid resistance include acute vascular rejection, mononuclear cells at endothelial cells of mall and large vessels in graft, immune response directed against vasculature, more extensive leukocyte infiltration iand C4d deposition in peritubular capillaries. Immune biomarkers of steroid resistance include increased cytotoxic T lymphocyte – NK cell signature (increased FasL mRNA, decreased FoxP3 in urine and increased dense granulation stain in biopsy), B lymphocyte signature (increased CD20 and B lymphocyte associated immunoglobulin in the graft), and intraglomerular and interstitial macrophage signature (CD68) as well as increased CD25-CD3e ratio and LAG-3 (lymphocyte activationgene-3). Non-immune biomarkers include removal of zinc ion by increased intragraft metallothioneins (MT) and TIMP-1 (tissue inhibitor of metalloproteinase-1) and F2R (coagulation factor II receptor). Decreased GR expression has been associated with reduced ratio of GRalpha/ GRbeta.
So steroid resistance has multiple factors and T cells with macrophages play important role in steroid response to the rejection.
A kidney biopsy with DSA should be done as early as possible in suspected rejection. in absence of response to steroids within 5 days, possibility of steroid resistance is high and hence ATG administration should be considered, if DSA negative and no evidence of AMR. Early use of second line treatment improves graft prognosis.
The changes in my practice after going through the article:
1) More vigilant to steroid resistance.
2) Early kidney biopsy
3) Zinc supplementation in acute rejection
4) Start ATG if no response after 5 days of starting steroid treatment.
5) Treat associated AMR (if biopsy evidence, DSA present) with IVIG/ plasmapheresis.
Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection .
Introduction:
The best modality of RRT in ESRD is Renal transplantation with improving quality of life but still acute rejection is a major challenges and one of the most common cause of poor graft outcome most of the attacks responding to anti-rejection measure especially glucocorticoid and other not responding so presence of biomarkers for steroid resistance rejection is important.
. Impact of acute rejection on graft outcome:
Incidence of acute rejection correlates with the graft failure and chronic allograft dysfunction, which depends on many factors such repeated attacks of rejection , type , time and responding to treatment or not.
. Treatment of acute renal allograft rejection:
1-Synthetic corticosteroids:
Idea started with increasing dose of daily maintenance steroid to treat AR, now pulse steroid is considered the cornerstone in treatment of AR.
2-Polyclonal and monoclonal antibodies:
It’s the first line of treatment steroid resistant acute rejection.
. Immuno-regulatory effects of corticosteroids:
In-brief GC led to downregulation of pro-inflammatory genes, GCs increase the expression of anti-inflammatory cytokines and transcription mediators which has a major role in rejection treatment which medicated via GR.
. Steroid resistance:
Majority of acute rejection cases in solid organ transplantation is responding to high dose GC but around 20-25 % partially respond or resistant to GC , and need other immunomodulatory drugs like ATG.
An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy.
. Assessment of risk for steroid resistance:
.1. Clinical and pathologic indicators of steroid resistant rejection:
Histological markers associated with liability of steroid resistant AR , mainly microvascular infiltration with inflammatory cells , leucocytes in PTC with C4d degradation in PTC with serological HLA DSA antibodies.
2. Prognostic biomarkers for steroid resistant rejection.
=Cytotoxic T lymphocytes and NK cells. The first immune component linked with resistance to anti-rejection treatment and graft outcome.
=Patients with steroid-refractory AR expressed increased intra-graft levels of the B cell marker CD20 and B-lymphocyte associated immunoglobulin.
=Immunostainings for CD68 revealed the presence of intra-glomerular and interstitial macrophages during AR as prognostic markers for steroid resistance and graft outcome.
=Non-immunological biomarkers.
A relatively novel finding is the link between zinc regulation and resistance to anti-rejection treatment with steroid.
=. Glucocorticoid receptor expression.
Decreased GR expression has been implicated as a cause of steroid resistance in a wide variety of diseases, including nephrotic syndrome , acute lymphoblastic leukemia [160], and asthma . The observed differences in GR expression between responders and non-responders might be a reflection of varying level of GR autoregulation which might be due to GR mutations.
. Clinical implications:
Steroid resistant AR is a multifactorial due to immunological and non-immunological causes like T cell and macrophages dominant and zinc dysregulation so we should be aware about this condition to avoid over dose of GC without benefit and also will gain side effects.
Conclusion
Acute rejection especially cellular rejection mainly responding to GC some time 20-25 % GC resistant AR, mainly dependent on many factors immunological and non-immunological (for example Zinc regulation and drug metabolism may play a role in the response to steroid therapy and features of ABMR with specific histological changes in renal biopsy).
How would this study change your practice?
Not all AR responding to GC.
Renal biopsy should taken as soon as possible and looking for histological features to decide regarding suitable treatment.
If not responding or stuck RFT start with ATG and if thee is features of ABMR start (IVIG+PE).
New biomarkers need more clinical evident studies.
III. Mechanisms and risk assessment of steroid resistance in acute kidney transplant rejection
Introduction
Acute rejection (AR) is a dominant risk factor for poor graft outcome.
AR is mostly a cellular immune response against mismatched donor antigens present on the cells of the allograft.
It occurs early post-transplant, with the highest risk in the 1st 3 months.
The majority of AR episodes are reversed with steroids, however 25-30% of cases fail to respond to steroids alone.
The diagnosis of steroid resistance, so far, mainly rests on the follow up of clinical parameters that reflect the graft function. It remains difficult to predict the response to anti-rejection treatment.
If steroid resistance could be predicted, it will prevent the unnecessary exposure to high-dose steroid therapy.
The impact of steroid-resistant rejection on graft outcome necessitates the search for a mean to assess the treatment response at an early stage of AR.
This article presents the current understanding of steroid-resistance in the setting of acute rejection.
It also gives an overview of biomarkers for the detection &/or prediction of steroid resistance in AR.
Treatment of acute allograft rejection
The immunosuppressive drugs used to decrease the occurrence of AR act by inhibiting the activation &/or effector functions of T cells.
Despite optimum HLA compatibility & use of induction & maintenance therapy, recipients can still develop AR.
Therapeutic options used for the reversal of AR include synthetic corticosteroids & polyclonal & monoclonal antibodies.
Steroids are used for both the prevention & treatment of AR.
High dose IV methylprednisolone is used in most centers as the 1st line treatment for AR.
ATG (a polyclonal antibody)is used only in steroid resistant rejections due to its risk of complications.
Corticosteroids
Anti-inflammatory & immunosuppressive effects are responsible for their therapeutic utility for the AR.
They exert protective effects on the allograft via direct & indirect regulation of immune-related gene transcription.
They suppress the inflammatory genes that are activated during AR, e.g. genes encoding for cytokines, chemokines, adhesion molecules, & inflammatory enzymes.
They also upregulate the expression of anti-inflammatory cytokines & transcription mediators.
Their other mechanisms include the prevention of leukocyte migration, induction of apoptosis in lymphocytes, & effects on the growth & lineage commitment of T cells.
The actions of GCs are mediated by the intracellular glucocorticoid receptor (GR) which have 2 isoforms, namely GRα & GRβ. The former is predominantly expressed, activated by GC binding & mediates most of the known immuno-modulatory effects.
Steroid resistance
In 25 – 30% of cases the AR cannot be reversed with corticosteroid therapy alone.
Such steroid-resistant patients require ATG, which results in a salvage rate of 70-90%.
AR is labeled as steroid resistant if the serum creatinine levels do not drop to within 120% of the baseline after pulse therapy with corticosteroids within 14 days after the start of the steroid.
The minimal time period for assessment of the response to steroids is 5 days after start of the pulse therapy.
Assessment of risk for steroid resistance
Prediction of steroid resistance at the time of biopsy obviate unnecessary exposure to high-dose corticosteroids
And would allow early introduction of salvage ATG therapy.
Clinical & pathologic indicators of steroid resistant AR
Parameters include:
– Acute vascular rejection
– presence of mononuclear cells at endothelial cells of vessels in the graft.
– presence of microvascular destruction the micro-vascular endothelium.
– extensive leukocyte infiltration into the PTCs.
– C4d deposition in PTC
Prognostic biomarkers for steroid resistant rejection
1.Immune biomarkers:
– cytotoxic T lymphocyte & NK cells.
– B lymphocytes: increased intra-graft levels of the B cell marker CD20 & B-
lymphocyte associated immunoglobulins
– Macrophages: Immunostainings for CD68 revealed intra-glomerular & interstitial
macrophages during steroid-resistant AR.
Challenges for biomarker identification in clinical context
The interpretation & validation of the prognostic biomarkers for graft outcome are difficult as the published data have diverse definitions, endpoints & patient cohort characteristics.
So later studies failed to verify the prognostic value of proposed immune biomarkers for steroid-refractory AR.
To overcome these challenges, the authors assessed the intra-graft expression levels of a panel of immunological markers with steroid responsive or steroid resistant AR.
The study showed that a combination of T cell activation markers CD25:CD3ε ratio & lymphocyte activation gene-3 (LAG-3) offers an improved prognostic value for assessing steroid response.
Non-immunological biomarkers
A novel finding is the link between zinc regulation & steroids-resistance.
Increased intra-graft expression of metallothioneins (MT) & tissue inhibitor of metalloproteinase-1 (TIMP1) is associated with steroid resistance.
Combination of immune- and non-immune biomarkers
No single biomarker can predict the steroid responsiveness with both high sensitivity & high specificity.
This is due to the fact that multiple mechanisms underly steroid resistance, as reflected by the heterogeneity in transcriptional regulation seen among AR biopsy samples.
A multivariate prediction model that combines multiple biomarkers could enhance both sensitivity & specificity of steroid resistance.
This model contains both immune (CD25:CD3ε ratio, LAG-3) & non-immune (MT-1, TIMP1, F2R) biomarkers as independent covariates. It offers a superior prognostic value .
Glucocorticoid receptor expression
Differences in response to GCs may be explained by variations in GR expression.
Decreased GR expression may cause steroid resistance.
The ratio of primary GRα & cytokine-induced GRβ isoforms might also impact responsiveness.
However, the link between GRβ expression levels & responsiveness to GCs could not be confirmed.
Genetic variability may also explain differences in treatment response. For example mutation in GR gene NR3C1 can affect the function of the GR & result in steroid resistance.
However very little is known about the relationship between GR expression & the response to GCs in the transplantation field.
Recent data, by the author, revealed no correlation between steroid refractory AR & the GR.
NR3C1 genotype distribution & GR expression levels were similar in kidney grafts from both responders & non responders to GC. More work is needed to confirm the role of the GR in recipients with GC resistance.
Clinical implications
Steroid resistance resides in specific cell populations, discussed above.
This may guide the treatment options of steroid-refractory AR.
Zinc regulation may play a role in this context.
Zinc intake might optimize GC responsiveness in recipients who express high intra-graft levels of MT & TIMP1 during AR.
.
The author found a multivariate prediction model cobining biomarkers related to different aspects of GC signaling.
This model offers a better prognostic value compared to conventional parameters & could identify non-responders who would benefit from immediate ATG treatment.
This may reduce exposure to high-dose GC, & may thus help avoid irreversible graft damage during the period that steroid-refractory AR is undertreated with steroids alone.
This models may also guide the development of novel therapeutic approaches.
This multivariate model that includes T cell activation markers & zinc regulating molecules as independent covariates, however does not reach 100% specificity & sensitivity for the prediction of steroid refractory AR.
Future perspectives
Validation & verification of the prognostic value of proposed biomarkers are required.
Prospective studies are needed before adopting these models in clinical practice.
The expression of microRNA transcripts is a relatively novel biomarker.
Analysis of microRNA expression profiles in graft biopsies may offer novel prognostic biomarkers for the outcome of AR.
Identification of non-invasive molecular markers in blood & urine may lead to earlier detection of graft dysfunction & timely intervention.
Conclusion
The response to high-dose GC for the AR treatment correlates with the expression level & characteristics of T cells & macrophages infiltrating into the allograft.
This is indicative that steroid resistance resides in specific cell populations & is not a feature of all lymphocytes.
Zinc regulation & drug metabolism play a role steroid-responsiveness during AR.
Additional zinc intake may optimize GC signaling & benefit transplant patients.
The use of a multivariate prediction model in practice might help a better assessment of steroid resistance & helps in the individualization of anti-rejection therapy.
The study, although presented huge information regarding steroid resistance & responsiveness, however it didn’t reach to a clear, conclusive & a reproducible non-invasive marker that would obviate the need for biopsy to delineate this dilemma.
However, the study gave good insights for the future works that should concentrate on prospective clinical studies.
So, at least for the present time, I would still stick to the current conventional practice in treating steroid-refractory transplant recipients.
Kidney transplantation is the best renal replacement therapy for ESRD. Despite the success of renal transplantation, approximately 40% of renal allografts fail within the first 10 years. Acute Rejection occurs in up to 10% of cases in the first year after transplantation. Diagnosis of acute rejection is based on clinical parameters and kidney biopsy results. It is difficult to predict the response to immunosuppression is based on clinical parameters and histopathologic assessment. Even after the introduction of immunosuppressive medication, AR continues to be a primary cause of renal allograft failure. the occurrence of AR correlates with a significant reduction in long-term allograft survival.
The treatment of acute rejection was historically as follows:
Synthetic corticosteroids
Early studies from 1960 demonstrated that episodes of acute rejection could be successfully managed with steroids. Side effects of steroids especially with the use of high doses were common.
In the 1970, anti-rejection treatment shifted to IV methylprednisolone instead of PO, to minimize the risk of side effects. Later studies evaluated both regimens and found them comparable in potency with fewer side effects with IV form.
Polyclonal and monoclonal antibodies
ATG therapy causes depletion of circulating T cells through mechanisms, including antibody- and complement dependent lysis and the induction of apoptosis. ATG is an effective treatment of AR with high graft survival rates. However, ATG has a lot of side effects including leukopenia, cytokine release syndrome, and viral infections.
Muromonab-CD3 is a monoclonal antibody which target CD3 molecule, which is associated with TCR. OKT3 therapy causes depletion of circulating T cells. OKT3 has been used as primary treatment of AR but associated with higher incidence of side effects compared to ATG.
The therapeutic effects of synthetic GCs are attributed to their anti-inflammatory and immunosuppressive effects. GCs regulate approximately 20% of all genes expressed in leukocytes. The major action of GCs is the suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes.
Steroid resistance
in approximately 25 to 30% of the patients the rejection episode cannot be reversed with corticosteroid therapy alone. However, ATG is effective in recipients with steroid-refractory rejection with successful rate of 70 to 90% Recipients of other solid organ transplants, including liver, lung and cardiac allografts have no response to steroids in acute rejection.
Prediction of steroid resistance at the time of biopsy could prevent unnecessary exposure to high-dose corticosteroid therapy and accelerate the administration of effective alternative treatment.
Several parameters have been associated with response to steroid treatment. Acute vascular rejection is related to resistance to high-dose steroid therapy and a subsequent higher chance of graft failure.
Unresponsiveness to steroid therapy has been associated with the presence of mononuclear cells at endothelial cells of large and small vessels in the graft.
steroid resistance is the presence of an immune response directed against the microvasculature.
Steroid-refractory AR has been associated with more extensive leukocyte infiltration into the peritubular capillaries (PTC).
C4d deposition in PTC has been associated with steroid resistance.
Non-immunological biomarkers
A relatively novel finding is the link between zinc regulation and resistance to anti-rejection treatment with steroids. Most important is metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) which are responsible for zinc regulation, it was found that increase graft expression of both may be associated with steroid resistance, thus there may be a rule of zinc supplementation in patients who express high levels of MT and TIMP1 during AR.
How would this study change your practice?
In clinical practice, knowing patients with acute rejection, who are resistant to steroids, alternative immunosuppression could be initiated instead, avoiding by this mean the side effects of steroids and giving better chance for the allograft to overcome rejection.
Review article
aim to assess the available biomarkers of steroid resistant AR and assess its complementary effect with the clinical and histopathological tools.
Introduction
————————
Acute rejection was the predominate cause of graft failure earlier in 1960 s with one-year graft survival was only 40% later on with the introduction of immunosuppressive therapy and improvement in the HLA crossmatching the graft survival improved significantly nowadays and the risk of AR reduced to < 15 % with improvement in the rate of early graft survival for more than 90, but still the 10-year graft survival reduced over time due to chronic rejection.
Acute rejection is due to the cellular immune response to the mismatched donor antigens more common in the first three months post transplantation and can be asymptomatic ,patients present with raising creatinine , and diagnosis based on clinical suspicion with the histopathological scoring of the graft biopsy diagnosis and classification based on Banff score characteristics including the assessment of the site type and degree of the inflammation in addition to the certain biomarkers that help in further assessment of AR and the likely response to treatments .
Many factors related to the AR episodes can predict the overall graft survival and outcome including the timing of AR , recurrence rate ,type of rejection and the response rate for the treatment , the late acute rejection most likely AMR can lead to chronic rejection or recurrence with progressive graft failure also acute vascular reaction with Banff class 11 associated with higher risk of graft failure in addition to the severity of AR and treatment failure also can lead to graft failure.
Treatment of acute renal allograft rejection:
Immunosuppression therapy used since 1950s for prevention and treatment of acute rejections by inhibiting the immune response mediated by the activation, effector T Cell cascades, kidney transplant recipients still at risk of acute rejections despite the optimization of the HLA crossmatching, use of induction and maintenance immunosuppression. Many therapeutic agents are availablefor the treatments of AR episodes.
Synthetic corticosteroids
Corticosteroids (GCs) used for both the prevention and treatment of AR since 1963.
Steroid, preferred PMP course s for treatment of AR with lower side effect than oral steroid, and nowadays PMP used as part of induction and also in treatment of acute cellular reaction while oral steroid is part of maintenance therapy in most centers .Steroids mainly act as anti-inflammatory immunosuppression agent that led to direct and indirect inhibition of cascades of inflammatory genes that lead to reduction of proinflammatory cytokine mediators, chemokines inflammatory mediators, and increase the anti-inflammatory cytokines and mediators
Around 25-30% of AR are not responsive to GC therapy.
Polyclonal and monoclonal antibodies:
1-ATG polyclonal T cell depleting agent from hoarse or rabbit act by different mechanisms as anti-body- and complement dependent lysis and the induction of apoptosis [61].
ATG is an effectives induction in high immunological risk and treatment of steroid resistant AR or recurrent ejections with favorable graft survival rates, its use limited due to higher risk of anaphylaxis, infection like CMV, BKV, and PTLD.
2-OKT3 monoclonal AB that act on CD3 pathway primarily potent T Cells depletion, previously used as induction therapy and treatment of steroid resistant rejection but due to side effects including sick sinus syndrome and serious infection was removed from the market since longtime.
Steroid resistant acute rejection:
Defined as an AR episode with failed response to pulse corticosteroids therapy within 14 days from initiation of treatment and patient’s serum creatinine levels not reduced by 120% from the pre-rejection baseline value [7,107–109]. the minimal time period for assessment of the response to steroids isfive days after initiation of the pulse therapy [96]. Failure for treatment of steroid resistant AR can lead to chronic rejection and progressive graft failure
Second line treatment by using Polyclonal antibody, ATG
Clinical and pathologic indicators of steroid resistant rejection:
presence of mononuclear cells at endothelial cells of large and small vessels in the graft [108]
·micro vascular injury Patients with moderate to severe microvascular destruction are less responsive to steroid compared to patients with only mild microvascular endarteritis [113]
more extensive leukocyte infiltration into the peritubular capillaries (PTC) (113).
Complement activation and C4 staining in the PTC indicate humoral anti HLA mediated immune response.
Prognostic biomarkers for steroid resistant rejection:
Immune biomarkers considered one of an important additional tools to assess the response to treatments and prognosis of AR episodes
New molecular genetic biomarkers directing on the identification of the lymphocyte populations that are associated with poor graft outcome. Resistance to GCs has been associated with increased expression of cytotoxic T lymphocyte-, natural killer (NK) cell-, B lymphocyte-, and macrophage signatures [99,101,120–12).
The bulk of CD8+ T cells infiltration within the allograft was linked to response of AR
treatment with GCs [123], while other molecular markers like increased mRNA expression levels of cytotoxic Tcell and NK cell (99), relatively high FasL mRNA expression [101] and dense granulysin staining (120) ,fasl RNA, low FoxP3 expression in urinary sediments [125] all correlated with refractory AR .
macrophage infiltration associated with intimal arteritis [132] and C4d deposition
in PTC [133] and steroid resistant AR.
B lymphocytes infiltration and B cells markers intraglomerular expression of CD20 and B-lymphocyte associated immunoglobulins associated with steroid resistant AR, [99,120,121].
the predictive value of immune biomarkers is hindered by molecular heterogeneity among kidney biopsy samples with AR. This observation may be a reproduction of the density of the mechanisms involved in response to steroid treatment, however the use of combination of biomarkers like (CD25:CD3ε ratio, LAG-3) and non-immune (MT-1, TIMP1,F2R) as independent covariates will offer a superior prognostic value for assessing responsiveness to GC therapy compared to both conventional clinical and histopathological indicators as well as single biomarker. This observation may be a reproduction of the density of the mechanisms involved in response to steroid treatment.
Zinc regulation may play a role in the response to steroid therapy during AR. Kidneytransplant recipients who express high intra-graft levels of MT and IMP1 during AR might benefit from extra zinc intake for optimal GC signaling, as High expression of metallothionein (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with steroid resistance [142].
Difference in glucocorticoid receptors expression ( GRβ and GRα) ,activation , GR genetic mutation will affect the response to steroid therapy in many diseases like asthma , nephrotic syndrome and lymphoblastic leukemia but in transplantation field not yet confirm its effect and need more studies
MicroRNA expression as a novel biomarker for response to steroid Therapy
Non-invasive methods for monitoring of graft outcome
Future perspective will be focusing on using noninvasive blood and urinary biomarkers for early and frequently assessing the graft dysfunction and help in timely intervention , still we need more studies for validation of the clinical use of many markers including peripheral blood mononuclear cells (PBMC) exposed to GCs which have been used to correlate gene expression profiles with clinical disorders, including steroid responsiveness [74,142,197–199].
Conclusions remarks:
Steroid resistant is complex and due to many immunological and nonimmunological factors like expression of certain types of T- lymphocytes, zinc regulating molecules effects A multivariate prediction model, containing biomarkers related to different aspects of GC signaling, offersthe best prognostic value for assessing steroid response.
will wait till the validation of these future promsing molecular genetic biomarkers we need more prosepctive studies to confrim thier value in the field of the kidney transplant we still depend on the clinical and histopathological evidence for diagnosis and treatment of steriod resistant AR . This review article shedding lights for the future move toward the use of noninvasive molecular biomarkers for early diagnosis and timely intervention to treat AR awhich can impact the graft survival and outcome.
Kidney transplant is the best option in patients with ESRD and successful rate of transplant reach to 90%. despite improvement in outcome of graft but still acute alo graft rejection within one year of transplant can happen at any time. Acute mediated rejection mainly due to cellular rejection and treated with pulse therapy of steroid & shows reverse graft rejection within 15 days. it’s difficult to predict graft rejection because early detection can manifested by clinically and histologically and early treatment can prevent graft loss. but in 20% of cases shows resistance to steroid. once steroids resistance predicated should be add IV ATG to avoid graft loss.
steroid resistance can predicted after initiation of steroid shows fail to decrease level of creatinine & histological show vascular injuries ( Banff calss II), T cell infiltration.
Steroid is potent anti inflammatory and immunosuppressive drug. Resistance to steroid can happen due to disturbance in regulating of steroid to suppress pro inflammatory genes ( chemokine / cytokines and molecular adhesion), inside nucleus of cell. In first 5 days from initiation of steroid; it’s difficult to differentiate from steroid response & resistance after 5 days if fail to reduce creatinine level indicating patients have resistance to steroid and should start ATG.
there’s Immunological and non immunological bio markers which are associated with steroid resistance:
Cytotoxic T cell lymphocytes & natural killer
Macrophage infiltration
B cell infiltration (CD20)
non immunological factors:
Metalloproteinase I // Metallothioneins
Coagulation factors Ii receptor
micro RNA transcription .
In our Practice should be monitoring serum creatinine daily & put possibility of drug resistance to steroid if fail decrease serum creatinine and should start ATG and plain patient for renal biopsy and according to banff classification detects type of rejection.
Acute rejection (AR) is a dominant risk factor for adverse graft outcomes. Even after the introduction of immunosuppressive medication, AR continues to be a primary cause of renal allograft failure. Various AR parameters determine the risk for adverse graft outcomes, including timing, recurrence, severity, and therapy sensitivity of AR episodes.
Treatment of AR episodes consists of:
Immunoregulatory effect of GCs:
Corticosteroids have both anti-inflammatory and immunosuppressive effects. These effects are obtained through direct and indirect regulation of immune-related gene transcription. The major action of GC is the suppression of inflammatory genes encoded for cytokine, chemokines, adhesion molecules, and inflammatory enzymes, GC also increases the expression of anti-inflammatory cytokines and transcription mediators, they can also prevent leukocyte migration, induction of lymphocytes death, and effect on the growth and lineage commitment of T cells.
steroid resistance:
Around 20-30% of rejection episodes can not be reversed by GC alone, and this poor response can happen in recipients of other organs such as liver, lung, heart. More rigorous immunotherapy is needed in such a case, such as ATG, which treat 70-90% of the cases.
AR episode is considered steroid-resistant when the patient’s serum creatinine level does not return to within 120% of the pre-rejection baseline value after pulse therapy with GC within 14 days after the start of the steroid therapy.
Assessment of risk for steroid resistance:
Future perspectives:
Acute renal allograft rejection negatively affect the long-term graft outcome, the diagnosis depends on clinical and histopathological assessment of graft biopsy, which can determine the severity but can’t predict the response to treatment.
Biomarkers of glucocorticoid (GC) resistant rejection may help in assessing the risk of poor graft outcome and the probability of response to anti-rejection treatment.
Treatment of acute rejection:
IV methylprednisolone is the first line of treatment with less side effects than oral prednisolone.
ATG therapy is mainly used for treatment of steroid resistant acute rejection and recurrent cases due to the risk of complications.
Steroid resistant:
It is a complex and multi-factorial condition, 25-30% of recipients may have rejection episodes which can’t be reversed with steroids and need more vigorous immunosuppression.
acute rejection episode is considered steroid resistant when serum creatinine fails to return to 120% of pre-rejection baseline within 14 days after pulse steroids.
minimal time period for assessment of response is 5 days after initiation of pulse steroid
Prediction of steroid resistance at time of biopsy allow avoiding:
Unnecessary exposure to high dose steroids
Development and progression of graft damage during the period of uder-treatment with steroids.
Clinical and pathological indicators of steroid resistant rejection:
Acute vascular rejection is related to resistance to high dose steroid.
Presence of mononuclear cells at endothelial cells of large and small vessels in the graft associated with steroid resistance.
Moderate to severe microvascular destruction responds less adequately to steroid therapy.
Extensive leucocyte infiltration into peritubular capillaries associated with steroid resistance.
It remains difficult to predict the response to steroids according to histopathological assessment.
Prognostic biomarkers for steroid resistant rejection:
Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness may provide complementary parameters for risk of adverse graft outcome.
Immune biomarkers:
Both T cells and macrophages have important role in response to steroid therapy.
Resistance to GC is associated with increased expression of cytotoxic T lymphocyte, NK cells, B lymphocytes and macrophage signatures.
The extent of CD8+ T cells infiltration within allograft correlated with response to treatment with GC.
Macrophage infiltration in the graft is related to response to GC therapy.
Challenges for biomarker identification in clinical context:
Clinical interpretation of these data is difficult as definition of steroid resistance and cohort characteristics vary in different studies, so the prognostic value of proposed immune biomarker can’t be verified.
Non-immunological biomarkers:
A recent finding is the link between zinc regulation and steroid resistant acute rejection.
Recipients who express high intra-graft levels of MT and TIMP1 during acute rejection might benefit from extra zinc intake for optimal GC signaling
Coagulation factor II receptor (regulator of intracellular signaling pathways) may affect GC action and need further research to determine the mechanism.
Combination of immune and non-immune biomarkers:
No single biomarker can predict the response to steroid treatment.
Combination of biomarkers could improve sensitivity, specificity and predict the response to GC in treatment of acute rejection.
How would this study change your practice?
Steroid resistant acute rejection can’t be predicted through histopathological assessment.
Recipients with acute rejection may benefit from extra zinc intake which may have a role in response to steroid therapy.
Acute rejection AR occurrence negatively affects graft outcome, it occurs more in the first three months post-transplant, once it happens, no one can predict its response to the treatment and extent of its negative impact on the graft outcome.
AR is reduced in incidence after introduction of immunosuppression medications from 90% to 15%, also there is substantial improvement of short-term survival at one year, but long-term survival has marginal improvement at 10 years. in spite of all of these , AR remains the first cause of graft loss, also it affects the occurrence of CAN chronic allograft nephropathy (IFTA) ; interstitial fibrosis and tubular atrophy which leads to graft loss after 1 year.
Treatment of acute renal allograft rejection:
1- Steroid the first medication used to treat and prevent rejection, high dose oral steroid oral prednisolone is required to maintain the status of no rejection or prevent rejection but will induce its toxic GIT side effects because it is required with high doses, so intravenous methylprednisolone used in high dose in induction of immunosuppression hence prevention of rejection and also in treating acute rejection episodes, and associated with less GIT side effects, so it is first line therapy.
2- Second line therapy is ATG antithymocyte globulin which is polyclonal antibody used in induction of immunosuppression and in treating resistant or severe cases of acute cellular rejection, it is antibody depleting agent but has some side effects like pancytopenia, fever, chills, headache, cytokine release syndrome /storm
Steroid has direct and indirect effects on immune related gene transcription, it suppress inflammatory genes which are 10-100 genes and also it increase anti-inflammatory cytokines, and it induces apoptosis of lymphocytes and prevent leucocyte migration hence prevent all consequences of acute rejection.
Steroid resistance :
Diagnosis of steroid resistance primarily relies on posttransplantation follow-up of clinical parameters reflecting renal allograft function. An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy
The minimal time period for assessment of the response to steroids is five days after initiation of the pulse therapy [
This untreated resistant cases can lead to chronic graft loss, so ATG should be used to treat these resistant cases.
Pathological indicators of steroid resistant cases:
1- Acute vascular rejection
2- presence of mononuclear cells at endothelial cells of large and small vessels in the graft
3- immune response directed against the microvasculature ; Patients with moderate to severe microvascular destruction respond less adequately to steroid therapy compared to patients with only mild destruction of the microvascular endothelium
4- more extensive leukocyte infiltration into the peritubular capillaries (PTC)
5- C4d deposition
my practice ; if there is no or little response to 3- 5 days pulse steroid, will do biopsy and start ATG until the result of biopsy appeared which may result in AMR and need plasmapharesis and ivig
Impact of acute rejection on graft outcome
The one-year graft survival rates exceeded 90% on short-term , the long-term graft outcome advance is not enough .
10% of graft failure was due to acute renal allograft rejection.
Renal interstitial fibrosis and tubular atrophy (IFTA) is the most common cause of chronic allograft failure after the first post-transplant year.
Risk of graft failure increases with time after transplantation , being more common to occur 3 months or more after transplantation , also those with recurrent AR episodes, and those with acute vascular rejection and cases resistant to therapy have a higher risk of graft failure .
Acute renal allograft rejection treatment
Therapeutic options for AR episodes treatment
-Corticosteroids
Both IV and oral steroids are successful in treating AR ,in fact pulse therapy with intravenous methylprednisolone has less side effects than oral prednisone therapy that is why intravenous pulse therapy with high-dose methylprednisolone is applied.
–Polyclonal and monoclonal antibody
ATG derived from rabbits and horses injected with human lymphocytes .
ATG therapy depletes circulating T cells by antibody- and complement dependent lysis and inducing apoptosis.
ATG is effective but can lead to side effects as leukopenia, cytokine release syndrome, and viral infections because of that it is saved for treating steroid resistant and recurrent AR.
Immunoregulatory effects of corticosteroids
Is due to it’s anti-inflammatory and immunosuppressive effects through direct and indirect regulation of immune-related gene transcription.
It’s main action is the suppression of inflammatory genes including genes encoding for cytokines, chemokines, adhesion molecules, and inflammatory enzymes and increase the expression of anti nflammatory cytokines .
Corticosteroid signaling
After administration, GCs diffuse across the cell membrane and bind to the cytoplasmic GR, the cytoplasmic GRα is associated with an inhibitory complex. This association stabilizes the hormone-responsive form of the receptor when ligand-induced activation occurs , the GR changes and dissociates enabling rapid translocation of the GC-GR complex to the nucleus regulating gene transcription through direct and indirect signaling pathways. These pathways inhibit the transcription of pro-inflammatory molecules, it’s alteration can lead to steroid resistance.
Steroid resistance
Steroid-resistant rejection cases are treated with ATG, with response rate of 70 to 90%
steroid resistance is diagnosed after pulse steroid therapy is given for 14 days and the serum creatinine level do not return to within 120% of the pre-rejection baseline value ,meanwhile 5 days are needed after start of pulse therapy to assess the response.
Assessment of risk for steroid resistance
Indicators of steroid resistance
Acute vascular rejection and the presence of mononuclear cells at endothelial cells of large and small vessels in the graft is related to resistance to high-dose steroid therapy .
Cases with mild destruction of microvascular endothelium respond better to steroid therapy more than those with moderate to severe destruction.
Circulating leukocytes target HLA molecules expressed on the PTC, leads to cellular rejection.
Prognostic markers of steroid resistance rejection
Immune biomarkers
The presence of T lymphocytes and natural killer cells are the first to appear and the extent of CD8 infiltration correlates with response to steroids .
B cell infiltration in a renal allograft can differentiate between steroid resistant and steroid response AR .
The presence of intraglomerular and interstitial macrophages are prognostic markers for steroid resistance also macrophage infiltration is associated with intimal arteritis and C4d deposition.
The expression of a broad panel of immunological markers within renal allografts with steroid responsive or steroid resistant AR was evaluated.
A combination of T cell activation markers CD25:CD3ε ratio and lymphocyte activation gene-3 (LAG-3) provides a prognostic value for assessing steroid response.
Non immunological biomarkers
The resistance to steroids therapy was associated with Zinc regulations indicating that Zn can be given to reduce steroid resistance
Intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is accompanied with steroid resistance .
TIMP1 can diminish the zinc-requiring anti-inflammatory effects of the GR.
Combination of biomarkers
Can increase sensitivity and specificity, and enables better risk assessment of steroid resistance .
Glucocorticoid receptor expression
Response variation to treatment with GCs can be due to variations in GR expression.
Future perspectives
Validation of the prognostic value of biomarkers
MicroRNA expression as a novel biomarker for response to steroid therapy
Non-invasive methods for monitoring of graft outcome
This study can change my practise
by shedding light on
-the new prospectives of searching for non invasive prognostic markers for steroid resistance other than invasive biopsy by trying to combine both immunological and non immunological biomarkers and investigating new blood and urinary markers
-Zinc was recommended to be used for steroid resistance cases
· Acute rejection (AR) represents a great threat on allograft survival, its incidence nowadays about 15 % and considered responsible for graft loss in 10 % of kidney transplant recipients. It increase risk of chronic immune mediated graft damage (transplant glomerulopathy), previously known chronic allograft nephropathy (CAN).
· Initially, steroids addition and optimization of maintenance immunosuppressive therapy used to treat AR. However, IV pulse steroids are now 1st line of treatment of AR.
· Steroids act through binding to cytoplasmic receptors (GR), then conformational changes then translocation to nuclear receptors to control many transcription genes to:
o Increase transcription of anti-inflammatory mediators.
o Decrease expression of pro-inflammatory mediators as cytokines and chemokines.
· Diagnosis of clinical AR depends mainly on clinical parameters (rising creat) and the golden standard is allograft biopsy proven histopathological damage of the graft.
· 20-30% of AR episodes are steroid resistant (creatinine does not decrease to 120% of baseline, or remained increased by more than 20 % of basal level ) after pulse steroids after 14 days of pulse steroids.
· The definition of steroid refractory AR remains variable and cut off level duration to assess response to pulse steroids also variable, but most of studies concluded that 5 days is minimal duration to determine steroid response.
· Those cases can be treated by r ATG with effective response in 70-90 % of cases.
· Some clinical predictors of steroid refractory AR:
o Late onset after 3 months, recurrent episodes of AR, no response to pulse steroids after 5-7 days.
· Some histopathological evidence of steroid resistance are :
o Vascular rejection (Banff II or III).
o Evidence of microvascular inflammation.
o Mononuclear infiltration at endothelium of blood vessels
o Extensive leukocytes infiltration in ptc.
o +ve c4d in ptc (indicating activation of complement system).
· Early detection of steroid resistant AR is crucial to avoid toxic effects of large steroid dose and to allow start of alternative therapy to salvage the graft. Hence, continuous research to find biomarkers for prediction of steroid resistance rather than pathological markers.
· Till now, no single biomarker with adequate sensitivity and specificity.
· Immunological biomarkers as:
o Increased B cell markers as CD 20 and Ig.
o Increased CD 8+ T cytotoxic and NK cells markers (high fasL mRNA, or decreased urine foxp3).
o T cell activation marker (CD25:CD3)
o Increased marker of macrophage infiltration (CD68).
· Non immunological markers:
o Increased expression of metallothionines (MT) which decrease zinc ions required for GR signaling.
o Inhibition of metalloproteinase.
o Role of GR downregulation which is evident in nephrotic syndrome and bronchial asthma, not proved in field of transplantation (need further research).
Q. implications of the study?
· Combined clinical and pathological evidence are the only or widely used tools till today to detect steroid resistant rejection as early as possible
· Further studies to detect best biomarker to detect steroid refractory AR.
· Zinc supplementation may help in improving response to steroids.
Acute rejection impact on the kidney
· Chronic allograft nephropathy and IFTA
· Reduced graft survival and graft loss
Episodes of acute rejection whether it is early or late are generally associated with poor graft survival but not all episodes are associated with the same impact on the kidney , this may depend on some factors:
Current treatment of acute TCMR
1. Pulse methylprednisolone followed by oral prednisolone taper
2. Augmentation of immunosuppressive medications
3. ATG (deplete T cells) used only in TCMR with Banff grade > IA especially if resistant to CS
Corticosteroids in treatment of AR
This time delay to asses steroid sensitivity may have bad impact on the graft thus it is important to anticipate steroid resistance, the following are parameters that can be used to assess steroid responsiveness :
1. The presence of acute vascular rejection in graft biopsy
2. Presence of mononuclear cells at the vascular endothelium of small and large blood vessels
3. Moderate to severe microvascular endothelial destruction
4. Aggressive inflammatory cell infiltration of PTCS
5. C4d staining of PTCS
6. Immunologic biomarkers : since the Type of infiltrating lymphocyte population may alter steroid responsiveness, cytotoxic T lymphocyte (CD 8 +), NK cells, macrophages (CD68), B lymphocytes (CD 20)are associated with steroid resistance, immune biomarkers includes CD25:CD3ε ratio andLAG-3
7. Non immunologic biomarkers : most important is metallothioneins (MT) and tissue inhibitor ofmetalloproteinase-1 (TIMP1) which are responsible for zinc regulation, it was found that increase graft expression of both may be associated with steroid resistance, thus there may be a rule of zinc supplementation in patients who express high intragraft levels of MT and TIMP1 during AR
8. Glucocorticoid receptor expression but currently no correlation found between steroid responsiveness sand GC receptors
How would this study change your practice?
with poor prognosis
Thank you Sherif
If creatinine level for example is 1mg/dl before rejection (baseline) and reach to 3mg/dl after rejection, and we started steroid for the treatment of AR, if serum creatinine fail to return to 1.2 mg/dl (120% of the baseline) at 2 weeks after treatment of rejection, this is called steroid-resistant AR.
This definition is not practical since I should wait for 2 weeks to assess steroid responsiveness, in practice we start treatment with either steroids or steroid + ATG according to Banff classification from the start with an assessment of creatinine daily or every other day according to the severity and after discharge, creatinine is monitored in weekly basis till reaching the baseline.
Please give a summary of this article;
Resistance to steroid therapy is a complex and multi factorial condition, in which both immunological and non-immunological factors can be involved. The response to high-dose corticosteroid therapy for the treatment of acute renal allograft rejection correlates with the expression level and characteristics of T cells and macrophages infiltrating into the renal allograft. These findings indicate that steroid resistance resides in specific cell populations and is not a feature of all lymphocytes.
The therapeutic effects of synthetic GCs for the treatment of acute renal allograft rejection are attributed to their anti-inflammatory and immunosuppressive effects.
The major action of GCs is the;
1- suppression of inflammatory genes that are activated during AR, including genes encoding for cytokines, chemokines, adhesion molecules, and in flammatory enzymes .
2- down regulation of pro-inflammatory genes, GCs increase the expression of anti- inflammatory cytokines and transcription mediators].
3- glucocorticoid (GC) therapy can suppress AR through a variety of other mechanisms, including the prevention of leukocyte migration, induction of cell death in lymphocytes, and effects on the growth and lineage commitment of T cells .
4- indirect suppression(trans-repression) of pro-inflammatory genes that are activated during AR .
An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy . The minimal time period for assessment of the response to steroids is five days after initiation of the pulse therapy .
Prediction of steroid resistance at the time of biopsy could;
1- prevent unnecessary exposure to high-dose corticosteroid therapy.
2- The development and progression of irreversible nephron loss during the period that steroid resistant AR is undertreated with steroids alone could be avoided.
Biomarkers for molecular and cellular mechanisms involved in graft survival and medication responsiveness could provide complementary parameters for assessing the risk of adverse graft outcome
1. Immune biomarkers; allograft-infiltrating inflammatory cell types, were found to be informative with respect to therapy response (immune (CD25:CD3ε ratio, LAG-3) .
2- Non-immunological biomarkers (MT-1, TIMP1, F2R)
3- Combination of immune- and non-immune biomarkers
combination of biomarkers in a multivariate prediction model could enhance sensitivity and specificity, and facilitate risk assessment of steroid resistance in patients suffering from AR.
4-Glucocorticoid receptor expression; Decreased GR expression has been implicated as a cause of steroid resistance in a wide variety of diseases, including nephrotic syndrome , acute lymphoblastic leukemia , and asthma . The ob-served differences in GR expression between responders and non responders might be a reflection of varying levels of GR autoregulation.
Clinical implications;
1-Investigations of immune-related biomarkers revealed that both T cells and macro- phages play an important role in the response to steroid therapy. Combined, these findings indicate that steroid resistance resides in specific cell populations. This may guide the therapeutic approaches for treatment of steroid-refractory AR episodes.
2- Zinc regulation may play a role in the response to steroid therapy during AR. Kidney transplant recipients who express high intragraft levels of MT and and TIMP1 during AR might benefit from extra zinc intake for optimal GC signaling.
3- Molecular heterogeneity among biopsy samples may explain the difficulties in validating the prognostic value of previously proposed biomarkers for steroid resistance. In addition, it demonstrates the importance of using internal and external validation techniques to verify the robustness of potential biomarkers.
4- a multivariate approach could identify patients with insufficient response to anti-rejection treatment with GCs, who would benefit from immediate ATG treatment.
5-Availability of a multivariate biomarker model in the clinic may lead to reduced exposure to high-dose corticosteroid therapy. More importantly, it may help avoid the development and progression of irreversible nephron loss during the period that steroid-refractory AR is undertreated with steroids alone.
6-multivariate models provide insight into the causative mechanisms in steroid-refractory AR episodes, which may guide the development of novel therapeutic approaches.
Future perspectives;
1- Validation of the prognostic value of biomarkers.
The prognostic value of the biomarkers should be confirmed in a prospective study before they can be introduced into the clinic.
2- MicroRNA expression as a novel biomarker for response to steroid
therapy Because of their relatively stable expression, microRNAs are emerging as potential biomarkers. Analysis of microRNA expression profiles in renal biopsies may lead to the identification of novel prognostic biomarkers for the outcome of acute renal allograft rejection.
3- Non-invasive methods for monitoring of graft outcome
Identification of molecular markers in blood and urine may provide means to monitor graft function more frequently, which could lead to earlier detection of graft dys function and timely intervention of the immune process.
How would this study change your practice?
I understand the importance of early diagnosis of steroid resistant acute rejection ( to prevent unnecessary exposure to high corticosteroid and development of irreversible nephron loss during period that steroid resistant AR undertreated with steroids alone could be avoided ) and kidney transplant recipients may benefit from additional zinc intake to optimize GC signaling.
Thanks Abdulrahman for your reply
Let us think about the definition of steroid resistant rejection. Ary you happy with the definition mentioned in the given article?
Incidence of AR from over 80% in the 1960s to below 15% nowadays.
one-year graft survival rates in excess of 90%.
Approximately 50% of grafts from deceased donors and 30% of grafts from living donors fail within ten years after kidney transplantation .
The graft attrition rates after the first year are between 3% and 5% annually. This is mainly due to death with a functioning graft and chronic allograft failure.
AR is also correlated with the development of chronic allograft failure.
Risk of graft failure –
increases as the time between engraftment and occurrence of AR increases, and is most pronounced with late AR episodes (occurring 3 months or more
after engraftment) .
patients experiencing repeated AR episodes are at greater risk of adverse graft outcome than those with no or only one episode .
patients with acute vascular rejection (Banff classification grade II) have a higher risk of graft failure compared to patients with acute tubulointerstitial rejection.
rejection episodes unresponsive to AR treatment.
Treatment of acute renal allograft rejection
Corticosteroids – pulse therapy with intravenous methylprednisolone is associated with fewer side effects than oral prednisone therapy.
Polyclonal and monoclonal antibodies- ATG is mainly used for the treatment of steroid-resistant AR and recurrent AR.
Immunoregulatory effects of corticosteroids-
GCs increase the expression of antiinflammatory cytokines and transcription mediators
prevention of leukocyte migration,
induction of cell death in lymphocytes,
effects on the growth and lineage commitment of T cells .
The actions of GCs are mediated by the intracellular glucocorticoid
receptor (GR).GRα is activated by GC binding and mediates most of the
known immunomodulatory effects. GRβ isoform expresses a different C-terminal region which inhibits GC binding.
Steroid resistance
in approximately 25 to 30% of the patients the rejection episode cannot be
reversed with corticosteroid therapy alone.
An AR episode is considered steroid resistant when the patient’s serum creatinine levels do not return to within 120% of the pre-rejection baseline value after pulse therapy with corticosteroids within 14 days after the start of the steroid therapy .
ATG treatment is generally required.
the minimal time period for assessment of the response to steroids is
five days after initiation of the pulse therapy.
This 5-day period is also the average time delay used by clinicians before considering a rejection as being steroid resistant.
Assessment of risk for steroid resistance-
Clinical and pathologic indicators of steroid resistant rejection-
Acute vascular rejection on biopsy.
presence of mononuclear cells at endothelial cells of large and small vessels in the graft .
presence of an immune response directed against the microvasculature.
more extensive leukocyte infiltration into the peritubular capillaries (PTC).
C4d deposition in PTC has been associated with steroid resistance.
Prognostic biomarkers for steroid resistant rejection
Immune biomarkers –
Cytotoxic T lymphocytes and NK cells.
B lymphocytes
Macrophages
combination of T cell activation markers CD25:CD3ε ratio and lymphocyte activation gene-3 (LAG-3) offers an improved prognostic value for assessing steroid response.
Non-immunological biomarkers-
Relatively high intragraft expression of metallothioneins (MT) and tissue inhibitor of metalloproteinase-1 (TIMP1) during acute renal allograft rejection is associated with steroid resistance. Increased intragraft MT expression may lead to removal of zinc ions that are normally used in GC signaling.
Differences in response to treatment with GCs may be explained by variations in GR expression.
The results of a questionnaire submitted to 17 transplant centers by Cantarovitch and Soulillou indicated that the mean period before considering a rejection as steroid resistant ranged from 3 to 7 d (median, 5 d).
Steroid-Resistant Kidney Transplant Rejection: Diagnosis and TreatmentH. ANDREAS BOCK
Steroid resistance has been defined differently by different groups, but most have defined it as non-response to therapy after 3-7 days (median 5 days). A study revealed that the creatinine response to steroid sensitive and steroid resistant rejection diverges after 5 days of steroids, hence if no response to 5 days of steroids, next line of treatment (ATG) should be given.
Waiting for 14 days to see the response is not prudent as the response to therapy would be better if initiated early.
Reference:
1) Bock HA. Steroid-resistant kidney transplant rejection: diagnosis and treatment. J Am Soc Nephrol. 2001 Feb;12 Suppl 17:S48-52. PMID: 11251032.
2) Shinn C, Malhotra D, Chan L, Cosby RL, Shapiro JI. Time course of response to pulse methylprednisolone therapy in renal transplant recipients with acute allograft rejection. Am J Kidney Dis. 1999 Aug;34(2):304-7. doi: 10.1016/s0272-6386(99)70359-8. PMID: 10430978.