3. A 57-years-old potential live donor for his cousin who is 46-years-old. The results of HLA match and crossmatch is shown below.
- Please comment on the HLA match and the crossmatch results shown below.
- What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
- Will you proceed for the direct transplantation?
- If yes, what is your immunosuppression protocol
- If no, what are the alternatives?
1)Please comment on the HLA match and the crossmatch results shown below.
HLA broad 022 split 122
DSA anti HLA B58 MFI 8488, anti HLA Bw4 MFI 7959
Positive flow cytometry to T and B cells
High immunological risk.
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
Broad mismatches less specific. Split mismatch more specific contributed to poor allograft outcome.
Will you proceed for the direct transplantation?
Nope
If yes, what is your immunosuppression protocol
Desensitization : Cycle plasmapheresis and IV IG.
Induction : ATG
Maintenance : Tacrolimus MMF Prednisolone
If no, what are the alternatives?
Pair kidney exchange program or deceased renal transplant.
Highly sensitised patient with high immunological risk
For desensitisation protocol
Plasmapheresis with IVIG and rituximab
Immunosuppression therapy steroid , tacrolimus and MMF
The broad 022
The split 122
HLA cross match
0-2-2 mismatch and 1-2-2 mismatch
Direct transplantation or not
The patient is highly sensitized and thus is of high immunological risk. This means we will not get good outcome post transplant without taking certain precautions. Getting a suitable donor will be of significant benefit in post transplant outcome in this patient. It will also significantly reduce complications. I would wait for a better donor. In addition, desensitization protocols with plasmapheresis and possibly rituximab is essential.
IS protocol
Desensitization using plasmapheresis , rituximab, IVIG
Induction therapy – ATG
Maintenance IS therapy – MMF, tacrolimus and prednisolone
Alternatives
Comment on HLA and the crossmatch
022 mismatch on the broad level
122 mismatch on the split level
positive B , T cell cross match, due to presence of DSAs B58 with MFI 8488
and Bw4 with MFI 7959
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
when do HLA typing on low resolution using serological methods we detect difference at antigen level( broad) , while high resolution typing using molecular methods will detect the allelic variant( split)
Opelz G et al.showed that matching for HLA split antigen resulted in better outcome than matching for broad HLA antigen.
Will you proceed for the direct transplantation?
No , the patient is highly sensitized
If yes, what is your immunosuppression protocol
do sensitization (plasmapheresis, IVIG plus Rituximab)
induction ( ATG/Almetuzemab)
maintenance therapy : Tac, MMF, steroid
If no, what are the alternatives?
wait for more compatible donor
or kidney paired donation
Please comment on the HLA match and the crossmatch results shown below.
· The HLA crossmatch showed 0-2-2 mismatch at the level of broad antigen and when taking the split Ag in consideration,the mismatch become 1-2-2.
· The crossmatch result showed positive T cell crossmatch which may be technical or lab error. Luminex or SAB technique should be considered.
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
· Split Antigen: Ag that has a more refined or specific cell surface reaction relative to abroad antigen. Example: HLA-B51 and HLA-B52 are split antigens of HLA-B5. In this case scenario A30 and A31 are split antigens.
· HLA mismatch was significantly associated with higher risks of overall graft failure, death-censored graft failure and all-cause mortality. Even split antigen mismatch was to be with adverse outcome on the graft survival.
Will you proceed for the direct transplantation?
Yes; I will proceed
If yes, what is your immunosuppression protocol
I will follow desensitization protocol(plasmapheresis, IVIG plus Rituximab)
For maintenance immunosuppression I will consider the triple of TAC, MMF and Prednisolone.
If no, what are the alternatives?
The alternative to this risky donation and transplant is:
· Exchange or Paired kidney Donation.
· Altruism
· Waiting list of deceased donation
Comment on the HLA match and the crossmatch :
Based on broad Antigens 1-2-2 mismatch (as HLA A30 , HLA A31 have the same broad antigens HLA A 19 )
Based on split Antigens 2-2-2 mismatch
Previous +ve flowcytometry crossmatch for both B and T cells
and now for T cells and Presence of DSA anti HLA B 58 ( MFI 8488 )
so the patients has high immunological risk of early AB mediated rejection.
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
Some Previously broad Antigens splitted into two or more split antigens for examples the A9 broad antigen was split to A23 and A24 split antigens, whereas the DR2 broad antigen was split to DR15 and DR16 split antigensHLA matching criteria may vary with regards to consideration of broad or split antigens. Split antigen matching appears to be more common and clinically important for HLA-A and-B antigens than for HLA-DR antigens with clinical significance depending on split antigens matching.
Yes affect the the transplantation outcomes as Split HLA antigen mismatch affect graft and patient outcomes like broad antigens mismatch, independent of donor type, initial immunosuppression, and even the presence of DSA
Will you proceed for the direct transplantation?
No as the patient has high immunological risk of early AB mediated rejection.
due to presence of DSA anti HLA B 58 ( MFI 8488 ) , and presence of Previous +ve flowcytometry crossmatch for both B and T cells and now for T cells.
If yes ?
First desensitization protocols according to local policy using plasma exchange ,Rituximab and IVIG
with reassessment of PRA by luminex before renal transplantation in addition to another flowcytometry crossmatch.
Use of ATG in induction in addition to Steroids , MMF and Tacrolimus based immunosuppression .
Protocol biopsy after transplantation and follow-up of DSA post Kidney transplantation for early detection of ABM rejection.
Alternatives ?
Desensitization protocols combined with Kidney paired donation program
Another compatible donor with less HLA mismatching.
References:
Hata Y, Cecka JM, Takemoto S, Ozawa M, Cho YW, Terasaki PI. Effects of changes in the criteria for nationally shared kidney transplants for HLA-matched patients. Transplantation 1998; 65 (2): 208.
Lim W, Chadban S, Clayton P, et al. Human leukocyte antigen mismatches associated with increased risk of rejection, graft failure, and death independent of initial immunosuppression in renal transplant recipients. Clin Transplant 2012; e-pub.
Please comment on the HLA match and the cross match results shown below.
o ABO incompatibility: Unknown.
o HLA matching: High level of mismatching at both the broad level (broad 022) and the split level(122). A30, A31are the split antigens of the broad antigen A19.
o Cross matching: This is a wet FCXM that was historically positive for both T and B cell with negative auto-cross match and recently positive for T cell but negative for B cell and auto- cross match. This positive T with negative B cell cross match may indicate a technical error, the presence of an autoimmune disease like SLE, treatment with Rituximab(a monoclonal AB) or the presence of non-HLA antibodies. This positive T cell cross match reflects the underlying presence of class I DSAs ;B58 with MFI 8488 and to the public antigen Bw4 whose DSA can cross-react with many antigens including B58(GREGs). CREGs minimize the chances to re-transplantation and account for the third party antibodies
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
Broad antigens ( super type) have poor specificity and they were identified at an earlier time with serological techniques, but the more advanced molecular DNA technologies enabled us to identify newer antigen subclasses called split antigens(subtype) which are the more refined cell surface antigens in relation to the broad ones. Split antigen matching is more specific and it is associated with better graft outcomes. In highly sensitized like the above patient, epitope matching is feasible but costly(high resolution typing) and has the benefit to identify acceptable and non-acceptable antigens.
Will you proceed for the direct transplantation?
I will not proceed to directly transplant this highly sensitized patient (HLA- B 58 and Bw4 with high MFI) because:
o Positive FCXM T cell cross match is a contraindication to transplantation.
o CDC cross match is not done, if positive , exclude this offer
o Check MCS, if > 250, exclude this offer. However, if MCS is <250, it is possible to proceed to this transplant after implementing a desensitization protocol to achieve a negative cross match.
If yes, what is your immunosuppression protocol
o Desensitization protocol: plasma exchange(3-5sessions) +IVIG(2 mg/kg) and possible Rituximab in some protocols.
o Induction with a lymphocyte depleting agent (ATG or Alemtuzumab)
o Maintenance immunosuppression: Triple therapy; Tacrolimus (maintain high trough level in the first few months between 8-10 ng/ml), MMF, Prednisolone.
o Follow DSA by Luminex SAB and possible protocol biopsy with following proteinuria level.
If no, what are the alternatives?
o Look for a better compatible living donor
o Keep on deceased donor waiting list.
o Paired Kidney Donation
References:
1- kidney transplantation handbook 6th edition.
2- kidney transplantation in adults :overview of HLA sensitization and cross match testing
up to date medicine 2022.
3- Tan MS, Wang M, Chang S-H, Al-Hamad T, Liu Ch. Association of Bw4/Bw6 mismatch across class I HLA loci with renal graft outcomes in first time transplants. Human Immunology. 2021 Oct; 82(10): 767-774
4- -Opelz G. Importance of HLA antigen splits for kidney transplant matching. Lancet. 1988 Jul 9;2(8602)
Broad HLA mismatch is: 0-2-2
Split HLA mismatch is: 1-2-2
HLA-A30 & HLA-A31 are split antigens for HLA-A19 broad antigen.
the broad antigen may consist of split antigens
split antigen matching has better outcome and impact on graft survival
this patient is high risk for tx so if we will proceed for direct tx he needs induction by ATG and triple Is medications with close monitoring and follow up
I prefer to not go for direct tx and enroll the patient in paired kidney donation program or trial for desensitization
Comment on the report:
ABO: Donor A+, Recipient blood group not mentioned.
HLA:
Broad mismatch: 2.2.0
Split mismatch: 2.2.2
What difference between broad and split mismatch?
Broad mismatch tests for a broad HLA antigen (A, B, DR). While split mismatch tests for more specific antigens split from the broad one.
What’s the impact of split mismatch on graft survival?
It was proven that the lower the split mismatch, the longer the graft survival.
Will you proceed with transplantation?
This is a case of a highly sensitized patient with a high mismatch, transplanting such a patient would carry a high probability of graft rejection.
I’d enroll the patient in a kidney paired exchange program looking for a more suitable donor.
If yes, what is your immunosuppression protocol?
For high-risk recipients;
Desensitization using: IVIG, Rituximab, plasma exchange, or immunoadsorbent.
Induction therapy: Depleting antibodies (ATG).
Maintenance therapy: CNI, MMF, steroid.
If not, what are the other options?
1. Enrol in a paired kidney exchange program looking for a more suitable patient.
2. Desensitizing the patient using one or more of the following protocols: IVIG, Rituximab, plasma exchange, or immunoadsorbent.
3. If in need for renal replacement therapy meanwhile, I’ll initiate peritoneal dialysis as it has better outcomes after transplantation compared to hemodialysis.
1- Please comment on the HLA match and the crossmatch results shown below.
HLA typing
– This is a report of HLA typing and flowcytometry crossmatch of patient (????) with a potential donor (????). unknown date .
– ABO group is masked.
– Broad mismatch :022
– Split mismatch :122
– Historical flow cytometry crossmatch was positive for both B &T cells. Except the sample dated 15/nov /2021 which shows negative FC CXM for B cell but positive FC CXM for T cell . this result is could be explained as a technical error(lab error ). As a FC CXM is a highly sensitive method for detection of DSA , appositive FC CXM make this patient of moderate risk group.
– The MFI for the DSA against HLA-B58 is 8488, and that against HLA-Bw4 is 7959.( significantly DSA- above the cut off )
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
Broad antigens are the antigens which composed of more than epitope ( immunologically active antigenic small molecule )and the antibodies against these antigen can react against these multiple epitope, and cross react with these epitope . accordingly the previously known antigens has been discovered(by modern molecular technique) to be be composed of more than one antigen ( called split antigens ) for example the broad antigen A19 is composed of two split antigens (A30-A31)
Split antigens are fractionated( specific epitope ) part of previously known broad antigens .
cross matching depending on split Ag has better short and long term outcome when compared to transplant outcome depending on broad Ag .
Will you proceed for the direct transplantation?
No because there is
· High miss match( Broad mismatch :022 , Split mismatch :122
· Two miss match at DR level .
· Patient is highly sensitized against HLA Ag (B58)
If yes, what is your immunosuppression protocol
First this patient will need a course of desensitization (plasmaphresis ,rituximab , IVIg )
Induction with ATG and maintenance with tacrolimus based triple medication (tac,prednisone ,MMF)
Monitoring with
· DSA
· Protocol biopsy
If no, what are the alternatives?
1. Waiting for another better cross matched donor.
2. Paired donor exchange .
· Please comment on the HLA match and the crossmatch results shown below.
· HLA 022 broad 122 split positive FXCM negative CDC cross match presence of DSA with high MFI .This high risk transplant .
· What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
· Broad antigen A19 {A30 and A31 split form } .HLA split result in better transplant out come .
· Will you proceed for the direct transplantation?
· This high risk transplant and live related donor I will not proceed .
If yes, what is your immunosuppression protocol
I can proceed with desensitization protocol with Plasma Exchange + rituximab + IVIg
Induction with ATG {available in my center }
Maintenance with Tacrolimus + MMF + Prednisone
·
If no, what are the alternatives?
To look for anther donor or pair exchange .
·
·
ABO: no available
HLA broad mismatch: 0-2-2
HLA Split mismatch: 1-2-2
DSA positive
Cross match positive
High risk donor offer.
I will not proceed because it is high risk donor offer.
The patient will need desensitization beforehand: Plasma exchange, IVIG, Rituximab.
Repeat cross-match and DSA before TX.
Induction IS: ATG or Almetuzumab
Maintenance: CNI, MMF, steroids
wait for more matched donor (living or deceased) or via paired kidney exchange program.
Please comment on the HLA match and the crossmatch results shown below.
there is a 0 2 2 mismatch at the broad antigen level
and 1 2 2 mismatches at split antigen
positive CXM (historical crossmatch)
last CXM positive T and negative B CXM which could be explained; by either technical error or non-HLA DSA, or low level DSA
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
surface antigen protein on the HLA molecules are termed broad antigen when first discovered these proteins then found to be consist of subunit proteins named splits antigen
for example A9 broad antigen consists of A23 and A24
the degree of match at split antigen level affects the graft outcome. the more the matching at the split antigen level the more favourable the graft outcome.
Will you proceed for the direct transplantation?
this case is high risk so, I will not proceed for direct transplantation.
positive crossmatch associated with high risk of hyperacute rejection. positive DSA with high level also increase the risk of rejection. positive anti-Bw4DSA can act against other antigens like A23, 24, 25, 32 B 13, 27, 37, 38, 44, 47, 49, 51, 52, 53, 57. 58. 59, 63. 77. as Bw4 is a public antigen so, crossreact with all of the above.
our patient has Bw 58 antigen
If yes, what is your immunosuppression protocol?
we need to do desensitization with plasmapheresis, IVIG, and Rituximab to achieve negative crossmatch
induction with ATG and maintenance with triple (Tac+ MMF+ steroid)
with post-transplant monitoring of DSA and possible protocol biopsy
.
If no, what are the alternatives?
Paired kidney donation
Please comment on the HLA match and the crossmatch results shown below.
Broad 0 2 2
Split 1 2 2
DSA HLA B MFI > 8000
FCXM Positive
CDC Negative
High-risk patient
Will you proceed for the direct transplantation?
No, highly sensitized patient. There is a need for pre-transplant care to reduce the risk of rejection. The ideal is to wait for a more compatible kidney or proceed with desensitization care with a protocol of rituximab, plasmapheresis, and immunoglobulins until acceptable DSA is achieved.
If yes, what is your immunosuppression protocol
rituximab, plasmapheresis, and immunoglobulins until acceptable DSA is achieved
rATG
CNI + MMF + steroids
If no, what are the alternatives?
Kidney paired donation or unacceptable antigens protocol
A] Please comment on the HLA match and the crossmatch results shown below.
B] What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
C] Will you proceed for the direct transplantation?
D] If yes, what is your immunosuppression protocol
E] If no, what are the alternatives?
REFERENCES
Hong Do Nguyen, Rebecca Lucy Williams, et al. The Evolution of HLA-Matching in Kidney Transplantation. February 13th, 2013. DOI: 10.5772/54747
Prabhaker Putheti, Vijay K SHarma, et al. T Cell Positive B Cell Negative Flow Cytometry Crossmatch (FCXM): Frequency, HLA-Locus Specificity, and Mechanisms Among 3073 Clinical FCXM Tests. May 2021. DOI:10.1101/2021.05.20.21257541
Abu Jawdeh BG, Cuffy MC, Alloway RR, Shields AR, Woodle ES. Desensitization in kidney transplantation: review and future perspectives. Clin Transplant. 2014 Apr;28(4):494-507. doi: 10.1111/ctr.12335. Epub 2014 Mar 12. PMID: 24621089.
Please comment on the HLA match and the crossmatch results shown below.
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
Each broad antigen are cell surface protein, which are made up 2 or more subunits, called split antigens, which bind to more specific antibodies.
Because of more specific antibodies binding with split antigen, split antigen matched graft has better outcome compared to relatively non specific Broad antigen matched. But it is easier to do broad antigen matching.
This is a high risk patient for Tx with high HLA mismatch, positive cross match and High level of DSA. I would not like to go for Tx now. Chances of rejection is very high.
If yes, then this patient needs desensitization with PreTx PE, IVIG and Rituximab and on reduction of DSA level to acceptable level, we can proceed with Tx with ATG as induction and triple immunosuppression of pred, tac and MMF.
Looking for another donor,
Enrol in paired kidney Transplantation,
or to continue on MHD
Please comment on the HLA match and the crossmatch results shown below.
Broad HLA mismatch is: 0-2-2
Split HLA mismatch is: 1-2-2
HLA-A30 & HLA-A31 are split antigens for HLA-A19 broad antigen.
T cell + B cell – crossmatch may indicate one of the following:
There is DSA against both HLA-B58(MFI=8488).
There is also anti-HLA-Bw4(MFI=7959).
Testing done more than 6 months ago; the date of transplantation is not defined.
========================================
· What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
·Broad antigen:
In the testing of cell surface antigens, a broad antigen is a serological specificity that is poor or broad compared to other specificities and can be defined as 2 or more split antigens.
Split antigen:
Is an antigen that has a more refined or specific cell surface reaction compared to a broad antigen.
Examples:
– HLA-A23 & HLA-A24 are split antigens of the HLA-A9 broad antigen
– HLA-A29,-A30,-A31,-A32,-A33,&-A74 are split antigens of the HLA-A19 broad
antigen.
– HLA-B51 & HLA-B52 are split antigens of the HLA-B5 broad antigen
– HLA-DR15 & HLA-DR16 are split antigens of the HLA-DR2 broad antigen.
– HLA-Cw9 & HLA-Cw10 are split antigens of the HLA-Cw3 broad antigens.
– HLA-DQ5 & HLA-DQ6 are split antigens of the HLA-DQ1 broad antigen.
——————————————————————–
Matching for HLA antigen “splits” results has a better transplant outcome than matching for “broad” HLA antigens.
At 3 years, there was an 18% difference between the survival rates of grafts with 0 or 4 mm among transplants typed for HLA-A and B antigen splits whereas the difference in transplants typed for broad antigens was only 2%.
Analysis of HLA-A, B antigens together with HLA-DR antigens showed an even greater advantage of matching for antigen splits. (4)
=========================================
· Will you proceed for the direct transplantation?
Bw4( and also Bw6) epitope is expressed by virtually all HLA-B molecules; it is also found on a few HLA-A proteins. Thus, high-level patient antibody to Bw4 (or to Bw6) will preclude transplantation with the majority of available donors.
This patient has high anti-HLA-Bw4(MFI=7959), high DSA against HLA-B54(MFI=8488).
So he is a highly sensitized recipient and it will be so difficult to proceed to transplantation with the current donor.
=========================================
· If yes, what is your immunosuppression protocol
If no other alternative donors and further waiting is not
Acceptable, one might decide to do desensitization with
a combination of apheresis and rituximab to reduce the
DSA to acceptable levels plus a negative cross match
Induction with ATG followed by a triple therapy with
tacrolimus, MMF, and prednisolone
========================================
· If no, what are the alternatives?
Enrolment in paired kidney donor program
Desensitization
Combination of PKD & desensitization:
– Two patients with ESRD, DSA against HLA- Bw4/ Bw6 & a positive FCM- B
cell XM were successfully transplanted in Belfast from a pooled pair
program after desensitization. (3)
Reference
1.Eurotransplant Manual© –version 2021 April 14. 20210 – subject to change
2. Charles T. Lutz.HLA Bw4 and Bw6 Epitopes Recognized by Antibodies and Natural Killer Cells. Curr Opin Organ Transplant. 2014 August ; 19(4): 436–441. doi:10.1097/MOT.0000000000000103
3.Mahendra NM, Miceal C, Aisling C and Jeanie M. HLA Incompatible Successful Renal Transplantation Across Bw4/Bw6 Alleles in Two Patients. Austin Transplant Sci. 2018; 3(1): 1007.
4. Gerhard Opelz IMPORTANCE OF HLA ANTIGEN SPLITS FOR KIDNEY TRANSPLANT MATCHING. The Lancet. https://doi.org/10.1016/S0140-6736(88)90001-3
comment on the HLA match and the crossmatch results
*ABO group :no data available.
*HLA Matching:
Broad antigen level : 0-2-2 mismatch as HLA A 30-31 are split to HLA A19
Split antigen level : 122 mismatch .
-negative auto crossmatch in the 3 samples
-Positive FCXM of both B& T cell except for B cell which was negative on 15-11-2021only after 2 positive results they may occur with technical error or Non HLA antibodies.
* high DSA cumulative level
(HLA B58 MF 8488, HLA Bw4 MFI 7959).
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
Broad antigens have poor specificity and they can be divided into 2 or more split antigens that have more specific reaction than the broad antigens
Will you proceed for the direct transplantation?
This patient is very high risk patient due to :
-Increase numbers of mismatches especially DR
-positive crossmatch
-high DSAs MFI
All these factors are associated with high risk of rejection.
So i would recommend to find more matched donor.
If yes, what is your immunosuppression protocol
This is very high risk patent
Desensitization : Plasma Exchange and low dose IVIG ,Rituximab.
Till negative cross match and low DSA titer .
Induction with ATG
Maintenance on triple immunosuppression Tacrolimus based with high level
Follow up of DSA and protocol biopsy in the first is very important for early detection of ABMR
If no, what are the alternatives?
Paired kidney exchange.
Dear Dr Farag
This is a copy and paste from a colleague’s (Mohamed Mohamed) reply. This is very unethical; therefore, you have been referred to the Academic Integrity Officer for investigation. See below:
Mohamed Mohamed
12 days ago
Please comment on the HLA match and the crossmatch results shown below.
Broad HLA mismatch is: 0-2-2
Split HLA mismatch is: 1-2-2
HLA-A30 & HLA-A31 are split antigens for HLA-A19 broad antigen.
FCM-XM positive for both B & T cells
There is DSA against both HLA-B58(MFI=8488).
There is also anti-HLA-Bw4(MFI=7959).
Testing done more than 6 months ago; the date of transplantation is not defined.
========================================
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
·Broad antigen:
In the testing of cell surface antigens, a broad antigen is a serological specificity that is poor or broad compared to other specificities and can be defined as 2 or more split antigens.
Split antigen:
Is an antigen that has a more refined or specific cell surface reaction compared to a broad antigen.
Examples:
– HLA-A23 & HLA-A24 are split antigens of the HLA-A9 broad antigen
– HLA-A29,-A30,-A31,-A32,-A33,&-A74 are split antigens of the HLA-A19 broad
antigen.
– HLA-B51 & HLA-B52 are split antigens of the HLA-B5 broad antigen
– HLA-DR15 & HLA-DR16 are split antigens of the HLA-DR2 broad antigen.
– HLA-Cw9 & HLA-Cw10 are split antigens of the HLA-Cw3 broad antigens.
– HLA-DQ5 & HLA-DQ6 are split antigens of the HLA-DQ1 broad antigen.
——————————————————————–
Matching for HLA antigen “splits” results has a better transplant outcome than matching for “broad” HLA antigens.
At 3 years, there was an 18% difference between the survival rates of grafts with 0 or 4 mm among transplants typed for HLA-A and B antigen splits whereas the difference in transplants typed for broad antigens was only 2%.
Analysis of HLA-A, B antigens together with HLA-DR antigens showed an even greater advantage of matching for antigen splits. (4)
=========================================
Will you proceed for the direct transplantation?
Bw4( and also Bw6) epitope is expressed by virtually all HLA-B molecules; it is also found on a few HLA-A proteins. Thus, high-level patient antibody to Bw4 (or to Bw6) will preclude transplantation with the majority of available donors.
This patient has high anti-HLA-Bw4(MFI=7959), high DSA against HLA-B54(MFI=8488).
So he is a highly sensitized recipient and it will be so difficult to proceed to transplantation with the current donor.
=========================================
If yes, what is your immunosuppression protocol
If no other alternative donors and further waiting is not
Acceptable, one might decide to do desensitization with
a combination of apheresis and rituximab to reduce the
DSA to acceptable levels plus a negative cross match
Induction with ATG followed by a triple therapy with
tacrolimus, MMF, and prednisolone
========================================
If no, what are the alternatives?
Enrolment in paired kidney donor program
Desensitization
Combination of PKD & desensitization:
– Two patients with ESRD, DSA against HLA- Bw4/ Bw6 & a positive FCM- B
cell XM were successfully transplanted in Belfast from a pooled pair
program after desensitization. (3)
Reference
1.Eurotransplant Manual© –version 2021 April 14. 20210 – subject to change
2. Charles T. Lutz.HLA Bw4 and Bw6 Epitopes Recognized by Antibodies and Natural Killer Cells. Curr Opin Organ Transplant. 2014 August ; 19(4): 436–441. doi:10.1097/MOT.0000000000000103
3.Mahendra NM, Miceal C, Aisling C and Jeanie M. HLA Incompatible Successful Renal Transplantation Across Bw4/Bw6 Alleles in Two Patients. Austin Transplant Sci. 2018; 3(1): 1007.
4. Gerhard Opelz IMPORTANCE OF HLA ANTIGEN SPLITS FOR KIDNEY TRANSPLANT MATCHING. The Lancet. https://doi.org/10.1016/S0140-6736(88)90001-3
HLA Match and cross match results: The recipient is 57 year old offered a kidney from a 46 year old donor. We assume that the Blood group is compatible and proceed to analyze the other reports….HLA typing of the donor and the recipient are Broad HLA mismatch 022…At the split antigen mismatch 122…This is due HLA A 30 and A31 are both split antigens for HLA A19….The cross match report has been reported through the Flow cytometry and the DSA by Single antigen bead technique….The historical FCXM for T cell and B cell cross match were positive except for the last reading in which the T cell cross match is positive, but the B cell cross match is negative..Both T and B cell cross match are negative…..
a positive T cell cross match in the presence of negative B cell cross match implies Lab error or technical error or maybe due to non HLA antibodies….It needs to repeated another time for lab error. Mechanism for differential expression of T cell and B cell cross match are differential antigen expression between HLA class 1 and 2 antigen….
DSA is positive for HLA B58 MFI 8588 and HLA Bw4 with MFI 7959…HLA B58 is a rare antigen according the HLA nomenclature but there is a significant MFI titre, this is significant and hence it needs to be desensitized before transplant..
Broad and split antigen mismatch and outcomes: Broad antigens are HLA molecules with poor specificity and they can be divided into 2 or more split antigens that have more specific reaction than the broad antigen….So the split antigen becomes more specific than the broad antigen..The studies show that the graft outcomes with broad and split antigens mismatch is associated strongly..In a study published at the lancet in 1988 by Gerhald oplez et al, the difference in the survival at 3 years between grafts with 0 or 6 mismatches for HLA a, B, DR was 31% using the antigen split technique in contrast to 6 percent difference with broad antigens…studies from the UNOS registry showed that risk of graft failure is increased with the number of mismatches 13% graft failure with 1/6 mismatch and 64% in 6/6 mismatch…It has been shown that HLA mismatch increase the risk of denovo HLA antibodies of the Class II type…In the above all examples to predict the graft outcome we need better HLA typing based on split mismatches, which will get missed we analyze only the broad mismatch…
Will you proceed for Transplantation?
The donor and the recipient has higher HLA mismatch, Positive T cell Cross match and High DSA MFI values…It is not advisable to proceed for transplant without desensitization
If yes what is your immunosuppression protocol?
In FCXM, I would request for MCS..if MCS<250 we can proceed for desensitization..The DSA RIS is 5+5 score for the 2 DSA and the total RIS is 10..as the RIS <17, we can proceed for desensitization…
I would use Rituximab 375mg/m2 for 2 doses each given 1 week apart starting from minus 2 weeks before transplant..I would also use Plasmaphresis with IVIG 5 sessions with triple immunosuppression starting minus 2 weeks before transplant….I would repeat the T cell and B cell FCXM…B cell FCXM could be positive because of rituximab….I would expect a negative T cell cross match after desensitization…..
I would use Inj Antithymocyte Globulin 1-1.5mg/kg for 3 to 4 doses during and in the first few days after transplant depending on the differential count…I would maintain the patient on standard triple immunosuppression protocol after the transplant with tac level between 5 to 10mg/ml…I would do protocol biopsy after 1 month of transplant and monitor DSA SAB every month for 6 months……I would then monitor DSA annually..
If no what are the other options?
I would counsel the family for another suitable living donor if the above risks and strategy are not accepted….We can go for paired kidney exchange program …The patient can also get listed in the deceased donor program…But the problem is HLA Bw4 is a public epitope…Antibodies against this antigen will cross react with other HLA antigens and lead to DSA positivity against many HLA antigens …
Please comment on the HLA match and the crossmatch results shown below.
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
Will you proceed for the direct transplantation?
If yes, what is your immunosuppression protocol
If no, what are the alternatives?
▪︎comment on the HLA match and the crossmatch results
*ABO group :no data available.
*HLA Matching:
-There is 122 mismatch at split level .
-Where in broad antigen level there is 022 mismatch as the broad antigen HLA-A 109 splits to A 29,30 ,31,32,33,74.
-negative auto crossmatch in the 3 samples
-Positive FCXM of both B& T cell except for B cell which was negative on 15-11-2021only after 2 positive results they may occur with technical error or Non HLA antibodies.
* high DSA cumulative level
(HLA B58 MF 8488, HLA Bw4 MFI 7959).
▪︎What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
early discoverd major antigens are known as broad antigens these antigen later with advances in HLA typing broad antigen appeared to split to more specific antigenic alleles.
Matching at split level is better and improved outcome of transplantation.
As mismatch at split level was associated with poor graft survival.
▪︎Will you proceed for the direct transplantation?
This patient is very high risk patient with positive crossmatch, high DSAs MFI, 2 mismatch at HLA-DR
All these factors are associated with high risk of rejection.
So i would recommend to find more matched donor.
▪︎If yes, what is your immunosuppression protocol
This is very high risk patent
First desensitization with Plasma Exchange and low dose IVIG ,Rituximab
Tacrolimus and mycophenolate mofetil ti start befor transplantation
until crossmatch becomes negative and MFI below 3000 but this number is different between centres .
then induction with ATG or alemtuzumab and methylprednisolone intraoperatively
And maintenance on triple immunosuppression
Follow up of DSA and protocol biopsy in the first is very important for early detection of ABMR
If no, what are the alternatives?
Paired kidney exchange.
HLA mismatch 022 ( Broad ) , 122 ( split ) , as both A30 & A31 are split antigens for the A 19
FCXM is positive for both T & B cells ( which means either Class I Ab or Class I & class II Abs ) , except for the last test which was positive for T cells only ( which are more expressive of Class I HLA ) . The other explanation in general ( but not here ) is the presence of autoAbs ( here autoAb is negative )
DSA agianst HLA B58 with high MFI , DSA against HLA Bw4 ( again targeting B 58 )
Broad HLA Ag is the main Ag which can have split Ags private epitopes ) , Split HlA
matching has more impact on the Tx outcome
with this high mismatch 5/6 & DSA : No
Desensitization ( PLEX , IVIG , RItuximab ) till DSA is undetectable or XM turns negative , then induction with ATG , IV MP , Tacrolimus , MMF , keep on maintenance triple therapy
DSA monitoring ( as desensitized ) at day 4 , weeks 2,4,8 , 6 months , 1 year and annually , with protocol Bx
wait for a more suitable donor , share in KPD program
🍁* Broad HLA Ag mismatch 0.2.2(as A30 and A 31 are considered splits antigen for A19).
Split HLA Ag mismatch1.2.2
*T and B cell FCXM are positive except 1 negative B cell FCXM IN 12/11/2011 (which may be due to lab error )
T and B autoFCXM are negative .
DSA : anti HLA B58 which is a rare antigen (MFI 8488) and Anti HLA Bw4 which is a very common and these anti bodies may react to many other HLAs
ABO matching is not mentioned in the case
🍁Broad antigen is HLA Molecule with poor specificity
Divided into 2 or more split antigens with higher specificity and more accutate prediction of Graft outcome
🍁I will not proceed directly for this Tx because the patient is highly sensetized with very poor prediction of Graft survival
🍁if I have to proceed with this Tx
Adequate desensitisation is required with IVIG , Plasmapharesis and Retuximab
Together with induction with ATG
and triple Immunosuppressive drugs
Tacrolimus: Target trough level of 8-10 ng/ml
Mycophenolate mofetil (MMF): 1000 mg twice a day
Corticosteroids: Injection methylprednisolone 500 mg intravenous on the day of surgery, followed by tablet prednisolone 1mg/kg/day for 3 days and then 20 mg/day, to be tapered to 5 mg/day over next 6 to 8 weeks
With regular DSA testing
Once in 1st 3 months and then once yearly
🍁search for another living or deceased donor or paired exchange organ donation
A30 and A31 are split of A19 so, this HLA report is 0 2 2 broad and 1 2 2 split.
This pateint has positive T cell FCTXM current serum, and positive both T cell and B cell in the past in addition to the presence of DSA with high MFI, so highly sensitized, I will not proceed and better to lool for another donor.
This pateint for desensitization with plasmapgeresis, IVIG before transplant.
Induction with ATG or basiliximab and maintenance with triple MMF, TAC and prednisolone with follow up of DSA level.
protocol biopsies is advised.
other options either paired kidney exchange donation or deceased donor
1)HLA A30 and HLA A31are splits of HLA A19. HLA B58 is a split of B17. HLA B15, B40, and B58 are broad antigens. DR4 and DR3 are broad and DR11 is a split of DR5. Consequently, there are HLA A, B, DR 122 (split) and 022 (broad) HLA mismatches.
Both T cell and B cell flow crossmatch were positive most of the times. And anti HLA-B58 DSA was positive with high intensity (MFI more than 8000). In addition, anti HLA Bw4 DSA is positive with high intensity (MFI more than 7000).
Interpretation of HLA antibody reactivity should consider different HLA-Bw4 epitopes associated with HLA-B and HLA-A alleles.
The anti-HLA antibodies can react with ‘private’ epitopes, which are shared by very few other HLA allele products, or ‘public’ epitopes, which are encoded by many HLA alleles. Perhaps the most important public epitopes are Bw4 and Bw6. Either the Bw4 or the Bw6 epitope is expressed by virtually all HLA-B molecules; Bw4 is also found on a few HLA-A proteins.
Consequently, patient’s high-level antibody either to Bw4 or to Bw6 will preclude transplantation with the majority of available donor kidneys.
2) HLA antigens are first categorized into broad categories. Then, over time, HLA antigen classifications have evolved and it has allowed to detect differences in antigens and split antigens are recognized. For example, A23 and A24 are splits of A9 broad antigens. HLA splits antigen matching results in better transplant outcomes than HLA broad matching.
3) I suggest it is better not to proceed with direct transplantation, because of donor age, multiple HLA mismatch, highly sensitized recipient with presence of high intensity DSA, and positive both T-cell and B-cell flow cytometry as well.
4) If there is no other option, I will do pretransplant desensitization with plasmapheresis, IVIG and rituximab or possibly the more recently introduced complement inhibitor eculizumab, anti-CD20 obintuzumab, or IgG cleaving enzyme imlifidas.
I will consider induction therapy with ATG or Alemtuzumab and methyl prednisolone pulses and maintenance therapy with tacrolimus, MMF and a low dose of prednisolone.
5) Kidney paired donation is a better option for this patient. Although in the presence of anti HLA BW4 (public epitope), finding an acceptable donor is very difficult.
HLA broad mismatch is 022 because HLA- 30,31 are split antigens of A19.
HLA split mismatch would be 122
Current Flow X match is positive for T cell and negative for B cell though previously it was positive for both T and B cells indicating a technical error?
DSA against B58 is having MFI 8488 and against
Bw4 7959.
Bw4 is a public epitope shared by many HLA antigens including B58
Nothing is mentioned about CDC cross match and MCS for flow X match but with these DSA s it seems there will be significant channel shift and proceeding for Tx is not possible
Better matching for split Ag has lead to better transplant outcome.
This patient would require desensitization before transplant in case if he has no other donor
Best would be to enroll him in PKD program
1.In this report of HLA typing & FCXM dated 15/11/2021; HLA-A30,A31 are split antigens of HLA-A19 and therefore HLA mismatch are 022(broad) and 122(split). Latest FCXM was positive T cell and negative B cell. DSA against B58 at MFI of 8,488 and anti HLA Bw4 at MFI of 7,559. Ideally one would like to know the results of CDCXM & cPRA but in any case this is high risk patient due to the presence of positive FCXM & positive DSA
2.Split antigen are more refined and has specific cell surface reaction relative to broad antigen. recognition of HLA mismatching at the level of split antigen is associated with better transplant outcomes compared with broad antigen
3.This is high risk category due to positive FCXM & pre-transplant DSA, therefore is not advisable to proceed for direct transplantation.
4.If we decided to go then this patient will first require de-sensitization in form PP, IVIG, RTX prior to transplantation until FCXM is negative or DSA is below 3000. Induction protocol will be ATG & IV methypred followed by maintenance with tacrolimus, oral pred, and MPA. Post TX monitoring for DSA and protocol biopsies are essential in the first 3 months
5.If no , options are ; wait for compatible donor, enrollments in programs like USA KAS, Euro-transplant acceptable mismatch program, PKD
comment on this report:
there’s no comment on ABO compatible
This case is HLA incompatible with positive T cells and B cells but last flow cytometry positive for T cells and negative for B cells; it’s may be lab error
There’s presence of high level of DSA against B58 and Bw4
there’s mismatch ABC DR 022 broad and 011 split.
Broad antigen is serological specificity that is poor or broad relative to other specificities and can be defined as 2 or more split antigens.
Split antigen more specific cell surface reaction relative to a broad antigen and effecfive in matching than broad.
Split is more immunological difference than broad in outcome of graft survival.
I will not accept the case for kidney transplant because high immunological risk for rejection
If yes: induction with Iv ATG and pulse therapy of steroid and plasma exchange
Maintenance therapy are low dose steroid and MMF and Tacrolimus
* If no, what are the other options?
Looking for another compatible donor or Donor paired exchange program.
This is a histo-compatibility report showing HLA mismatch : broad is 0-2-2, split is 1-2-2(A30and 31 are split of A19)
The last FCXM (10 days before the result): T cell is positive and B cell is negative ( could be techniqual error ) with historical positive T and B. the autocross match is negative for both T and B cells.
There are DSAs against B58 with MFI 8488, Bw4 with MFI 7959
Broad mismatch use serology while split use molecular methods. This split was associated with better graft survival
This is high risk transplant as there are DSA with high MFI and 2 DR mismatch. So I would look for other options.
o Desensitization wit IVIG, Plasma exchange and rituximab
o ATG as induction
o Triple immunosuppressant as maintenance including tacrolimus
o Avoidance of steroid minimization or avoidance protocols
o Protocol biopsies and DSA level follow up
Exchange donation ,deceased donation , change into another related donor
Please comment on the HLA match and the crossmatch results shown below ?
Blood group not mention so we consider compatible.
Broad antigen 122
on level of split antigen 022
Patient has positive historic flow crossmatch for T and B lymphocyte bur recent flow crossmatch positive for T negative for B could due to technical error or non HLA Ab
DSA anti HLA B58 8488MFI,antiHLA Bw 7959MFI
So patient with high immunological risk .
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation
Broad antigen is common antigen or parent antigen previously consider similar but with advance technological study at the level of epitop they discover to be different ,as far as possible compatible donor at level epitop (split matching ) associated with successful transplant and superior short and long graft survival .
Will you proceed for the direct transplantation?
If we have no other choice and patient on prolong waiting list ,sure survival from transplantation with this risk better than stay on hemodialysis .
If yes, what is your immunosuppression protocol?
Desensitization protocol with plasma exchange ,IVIg, rituximab .
Induction with ATG .
Immunosuppressive drug (TAC based regimen ).
Post transplant DSA monitoring ,and protocol biopsy at 1 year .
If no, what are the alternatives?
Change the donor through allocation system.
or PKD (paired kidney donation ).
1.Please comment on the HLA match and the cross match results shown below.
HLA-A,B,DR broad antigen mismatch 022 while split antigen mismatch is 122
HLA-A19 is a broad antigen with HLA-A 30 and 31 are split antigens
Historic B cell and T cell were positive also the Auto X-m results showed negative both T & B cell excluding presence of autoantibodies
Current T cell is positivity which may indicate positivity in class I antigen witch are more expression on T lymphocytes. positive T and negative B cell cross match may be due to lab error.
DSA anti-HLA B58 with 8488 MFI and anti-HLA Bw4 with 7959 MFI (anti-HLA Bw4 is cross reactive epitope group and can bind to several antigens sharing the same public epitope including B58 that is present in the donor).
2.What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
*Broad HLA antigens are detected by serological methods and have split antigens e.g. A19 has A30 And A31.
Split antigens can be detected by molecular techniques.
HLA split mismatches give poor graft survival, while matching split antigens provides better graft survival.
3.Will you proceed for the direct transplantation?
No, i will not proceed for direct transplantation with DSA with high MFI and this positive cross match
4- If yes, will do desensitization by plasmapheresis and IVIG until negative CM obtained, and induction by ATG, maintain on Tac, MMF, prednisolone
5- If no, will go another donor or PKD program .
REF
1. Analysis of HLA-DR split-specificity matching in cadaver kidney transplantation; a report of the collaborative transplant study, G Oplelz et al, Transplantation,1997.
1-The crosshatch show that HLA-A,B,DR
broad antigen mismatch 022
split antigen mismatch is 122
HLA-A19 is a broad antigen (( HLA-A 30 and 31 are split antigens))
Previous B cell and T cell FCXM were positive twice while the last FCXM is positive only for T cell with negative B cell FCXM this indicate the presence of a HLA class I antigen
Negatives autocrossmatch
High titer of DSA against HLA class I ((B58,Bw4))
Bw4 is good example of a public epitope which is present in half of the HLA B molecules and in some HLA A molecules.
High risk transplant
2- split antigen is an antigen that has a specific cell surface reaction relative to a broad antigen. (Example: HLA-B51 and HLA-B52 are split antigens of HLA-B5)
Split antigens are considered sub groups of broad antigens, Split is more specific than broad antigen.
e.g., HLA-DR 6 (which is the broad ag), (DR13, DR14) (they are the split antigens for DR6).
Split is more specific than broad antigen and Split antigen compatibility is more important and it gives good graft survival and good graft outcomes
3-Because of positive T cell cross match, HLA mismatch, high titer of DSA more than 2000
all these factors make this transplantation having high risk for rejection
So I will not proceed this transplantation
4- If yes
We need to desensitization by PE , IVIG and rituximab until negative FCXM or positiveFCXM with MCS < 250
Induction with ATG 1.5mg / kg 500mg for 3-5 doses
Maintenance by TAG, MMF, steroid
monitor donor-specific antibody (DSA) levels monthly for the first three months posttransplant
then at months 6, 9, and 12,and annually thereafter.
Patients with persistent or de novo DSAs should be evaluated with a renal allograft biopsy to exclude the possibility of ABMR.
5-If no
I will wait for more compatible donor or paired kidney transplant
Reference
1-up to date
2-Applied Transplant Immunology; Case-based Discussion (Part 1) By Ahmed Halawa Consultant Transplant Surgeon Associate Professor University of Liverpool, Consultant Transplant Surgeon
Comment on the HLA match and the crossmatch results shown below:
This patient is considered of high risk, of high degree of mismatch.
HLA A; A30 and A31 are split antigens of broad A19.
No class B or C match at all, or DRB.
Cross match shows positive result for T cells, carrying high incidence of hyperacute rejection occurrence.
Two Positive B cell cross matches, followed by one negative cross match denoting desensitization trial (may be rituximab).
DSA also are encountered:
Anti HLA B 58 with high MFI EXCEEDING 8000, anti HLA Bw4 of MFI 7959, which are both too high values.
Broad antigen mismatch is 022, split antigen 122 mismatch.
Broad and split antigens and how their mismatches affect the outcome of the transplantation:
HLA antigen classifications have evolved over time with development of techniques that allowed the detection of differences in antigens (“split” categories) that were previously undistinguishable (“broad” categories). Advancements in DNA-based technologies have led to a switch from serological typing to high-resolution DNA typing methods.
Importance:
Analysis of HLA-A, B antigens together with HLA-DR antigens showed an even greater advantage of matching for antigen splits: the difference in survival at three years between grafts with 0 or 6 mismatches for HLA-A, B, DR was 31% when antigen splits were analyzed, in contrast to a 6% difference with broad antigens. This indicates that typing for HLA antigen splits is important in renal transplantation, that the potential benefit of HLA matching in renal transplantation is greater than currently accepted, and that HLA typing and kidney allocation routines should include them.
Proceeding for the direct transplantation:
Not advised in this case, owing to the high mismatch level, positive cross match, high MFI for DSAs would definitely cause serious bad outcomes if direct transplantation is proceeded up to losing graft and patient’s life.
If yes, immunosuppression protocol:
First desensitization should be performed properly ( rituximab ) until obtaining negative cross match and lowering DSA levels to acceptable values are mandatory before transplantation.
Triple therapy for immunosuppressive regimen (tacrolimus, MMF and corticosteroids) along with induction by ATG according to the center’s protocol.
Close monitoring to the patient clinical status, graft function and prophylaxis against possible complications is a must.
Keeping the FK level on the higher value is recommended in this patient unless there is a complication as infections or occurrence of side effects.
If no, the alternatives are:
Kidney paired donation program or better matched deceased donor program while remaining on renal replacement therapy according to his case either dialysis or conservative measures.
Please comment on the HLA match and the cross match results shown below.
ABO Matching- Not shown
HLA Matching-
HLA Broad Mismatch-0 2 2 ( A 19 has splits- A 30 and A31)
HLA Split Mismatch -1 2 2
Positive B& T cell FCXM- Negative auto cross match, B cell FCXM negative on 15-11-2021 ( this can be due to technical error, autoimmune conditions or Non HLA antibodies)
Anti HLA B58- MFI=8488
Anti HLA Bw4 MFI=7959
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
Broad HLA antigen are major antigens. Different HLA broad antigens have split antigens. HLA match at split antigen level has better graft outcome. For example in this Report we can see A 30 and A31. A 30 and A31 are splits of A 19
Will you proceed for the direct transplantation?
No- as this will be very high immunological risk due to HLA mismatches ( 2DR mismatches), Positive T cell FCXM, Positive B cell FCXM with negative current FCXM. Positive DSA with high MFI
If yes, what is your immunosuppression protocol
This will high risk transplantation and will require desensitisation protocols. Patient will require PLEX, IVIG and Rituximab till cross match is negative
Induction therapy with ATG
Maintenance therapy with triple regimen- Tac, MMF and Steroids
If no, what are the alternatives?
Wait for compatible donor and stay on dialysis
Paired kidney donation
Please comment on the HLA match and the crossmatch results shown below.?
HLA matching O22(broad)
122(split)
With DSA to B58 with 8488 MFI
Bw4 with 7959 MFI
With positive T and B cell cross match became negative after auto cross match which indicates IgM antibodies or non HLA antibodies
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
The broad technique done for the main antigen but the split technique the try to match the to subunits or alleles
The split technique associated with better outcome and graft survival
Will you proceed for the direct transplantation?
No ,this high risk patient with 2 DR mismatch,DSA and positive T and B cell cross match
Desensitization with plasmapheresis and retuximab should be done first
If yes, what is your immunosuppression protocol?
ATG induction and triple IS maintenance by Tac, MMF and predinsilone
If no, what are the alternatives?
Paired exchange
Please comment on the HLA match and the cross match result shown below ?
No data about ABO matching .
HLA mismatches are 0.2.2 by broad method and 1.2.2 by split method (HLA A30&31 are split antigen of HLA A19).
Cross match was positive for both T&B cells with a negative auto cross match, currently the cross match is negative for B cell which may be due to non HLA antibodies, previous treatment with rituximab orTechnical error.
There are DSA anti-HLA B58 with 8488 MFI and anti-HLA Bw4 with 7959 MFI (anti-HLA Bw4 is cross reactive epitope group and can bind to several antigens sharing the same public epitope including B58 that is present in the donor).
Immunologically this patient carries a high immunological risk as the HLA mismatches are 5/6 with 2 DR mismatches in addition to the presence of DSA and the positive cross match .
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
HLA typing can be done for broad antigen specificities or for their subunit antigen splits. Both broad and split mismatches impact the kidney transplantation outcome .Worse graft outcome had been found in a recipient with HLA-DR split mismatches .Decreased allograft survival is found in re –transplanted recipients with HLA-DR split mismatches .Also in cadaveric kidney transplantation split mismatches are found to be associated with decreased graft survival .Sub split mismatches are found to have a clinical relevance in kidney re transplantation . HLA-A19 is a broad antigen with several splits including HLA-A30 and 31 HLA typing at level of split antigens shows better correlation with graft survival than broad antigens.
Will you proceed for the direct transplantation?
No ,because there is an increased risk of hyper acute rejection .
If yes, what is your immunosuppression protocol?
1-Desensitization with plasmapheresis and IVIG till have negative FCXM.
2- Induction with ATG as high immunological risk and Triple TAC as maintenance therapy
If no, what are the alternatives?
Kidney paired donation
Reference ;
1-CTS Collaborative transplant study .Newsletter 2; 1997 may 1, 1997.
2-Analysis of HLA-DR split-specificity matching in cadaver kidney transplantation ;a report of the collaborative transplant study ,G Oplelz et al ,Transplantation,1997 .
3- Pratschke J, Dragun D, Hauser IA, Horn S, Mueller TF, Schemmer P, Thaiss F. Immunological risk assessment: The key to individualized immunosuppression after kidney transplantation. Transplantation Reviews. 2016 Apr 1;30(2):77-84.
Please comment on the HLA match and the crossmatch results shown below.
ABO matching not Shawn HLA matching: -Broad HLA Ag mismatch 0.2.2(as A30 and A 31 are considered splits antigen for A19). -Split HLA Ag mismatch1.2.2 Cross-match: Positive T and B cell FCXM with negative auto cross-match with the recent report of negative B cell CM which may be due to technical error, prozone effect, autoimmune disease like SLE, non-HLA antibodies . DSA: There is DSA against HLA class I (B58 with MFI 8488) and to the public epitope Bw4 Which Shared by many HLA antigens and can cause cross reactivities by a single anti HLA antibody.
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
Antigens is protein present on the cell surface and it is composed by the transcription of the DNA inside the nucleus.so we may have similar Antigens proteins on the cell surface but differ in the DNA inside the nucleus which is called the allelic difference .this mean that the sequence of the gene of the DNA bases is different but at the end when it translate it do so to similar proteins or antigens for example A9.
So previously they discover only the phenotype of the antigens which is for example A9 ,which has antibody A9 that interact with it and decide that the patient has antigen on cell surface which is A9.
With advancement of development, they discovered that this nomenclature is broad and it has another two subunits which is A23 and A24 for example . The difference between them that when they use more specific antibodies, it can detect each one separately and the difference between them is in the epitopes .
So they found that Antigen A9 is a broad and it’s in fact consist of 2 subunits which is A23 and A24 .
So they start to do the matching on the level of the split as well as on the level of the broad A9.
The split matching is more specific and more advanced which can detect the difference between A23 and A24 at the epitope on the top of the antigen arm, which are 2 arms and the difference between them only on a small area on the Antigens .
This is called the broad versus split matching .
Also there is another level of matching which is at the DNA level (at the level of alleles).
For example if donor recipient pair had A23 and A24 matching, they may mismatch at the level of alleles.
So the allelic matching is another level of matching which is more advanced .
There is large numbers of alleles for each gene and every year thousands of alleles are discovered.
Antigens level typing is called low resolution typing.
Complete typing called high resolution typing at level of alleles.
In other meaning serological versus molecular typing.
Typing for split antigens is more expensive and more difficult than typing for broad antigens.
For cadaveric renal matching, split is not necessary.
It is easy to find good match for broad antigens than for split antigens, because small numbers of antigens specificity done .
Will you proceed for the direct transplantation?
No, as it carries high immunological risk due to HLA mismatch including 2 HLA-DR mismatches, positive T cell FCXM historic and current, current B cell FCXM is negative with positive historic B cell FCXM, presence of DSA to class I with MFI>5000
If yes, what is your immunosuppression protocol?
Desensitization by PE and IVIG and Retuximab till the FCXM becomes negative
Induction by ATG
Triple maintenance IS
If no, what are the alternatives?
Waiting for more compatable donor
Or enrolled to the PKD program
Excellent
Please comment on the HLA match and the crossmatch results shown below.
57-year-old male being offered a kidney from a 46-year-old living donor. NO blood group mentioned so I assume its ABO compatible.
The HLA typing -HLA A B and DR reveals a 022 mismatch (broad antigen typing) and a 122 mismatch (split antigen typing). HLA A30 and A31 are split antigen for broad antigen A19.
The report shows a T and B cell FCXM with historical sera of the patient, all of which are positive, except with B cell FCXM which is negative on 15 November 2011. T and B auto FCXM are negative.
Positive T cell crossmatch in presence of a negative B cell crossmatch may be due to either a technical error, or non-HLA antibodies.
Anti HLA B58 (MFI 8488) and Anti HLA Bw4 (MFI 7959) were found
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
A broad antigen defined as HLA molecule with lack of specificity, and it can be divided into 2 or more split antigens having a more refined or specific cell surface reaction than the broad antigen.
As a broad antigen has lack of specificity while the split antigens are more specific.
Due to the advances in HLA typing, a group of HLA antigens which were previously considered broad antigens now they can be distinguished as split antigens.
The higher split mismatching is associated with poor graft outcomes. Study by Su et al which deduced that due to availability of better and more potent immunosuppression, HLA mismatch has lost much of its relevance.
Will you proceed for the direct transplantation?
Incremental mismatches in DR locus, positive T cell CXM (unknown MCS), and High-level DSA class I made it a high risk transplantation
If yes, what is your immunosuppression protocol
The MCS is lacking and high level of DSA
Desensitization might be considered, but it’s a risky transplantation
If no, what are the alternatives?
Change the donor – by either enrolling in a paired-exchange program or can remain on deceased donor waitlist till availability of a compatible donor
1)Opelz G. Importance of HLA antigen splits for kidney transplant matching. Lancet. 1988 Jul 9;2(8602):61-4. doi: 10.1016/s0140-6736(88)90001-3. PMID: 2898695.
2) Yacoub R, Nadkarni GN, Cravedi P, He JC, Delaney VB, Kent R, et al. Analysis of OPTN/UNOS registry suggests the number of HLA matches and not mismatches is a stronger independent predictor of kidney transplant survival. Kidney Int. 2018 Feb;93(2):482-490. doi: 10.1016/j.kint.2017.07.016. Epub 2017 Sep 29. PMID: 28965746.
Excellent
No blood group for donor, though Cross blood group transplant can be done. Now
successfully.
Patient is HLA Mismatch 022 Broad, 122 Split with Positive FCXM against T cells,
negative B cell.
The effect of DSA against the products of HLA class I and II genes in renal
transplantation are well described for class I (HLA-A, B and C), but still not clear for
class II .
A positive T cell CRXM in presence of a negative B cell indicate technical error or non-
HAL antibody.
Theirs antibodies, DSA against both HLA –B with 8488MFI and HLA Bw4 with 7959
the outcome of the transplantation?
Broad antigen is parent antigen, split is more specific as recently shown.
Matching for HLA antigen “splits” results in better transplant outcome than matching for
“broad.
No high risk patient.
Desensitization is needed, treatment consisted of:
1. First day after transplant: rituximab 375mg/m2, repeated with the same dosage on the
seventh day.
2. Plasmapheresis on days 3, 5 and 7 post-transplant, with IV immunoglobulin infusion
dosed at 0.5g/kg body weight following each session, with dose reinforcement of 1g/kg
on days 10, 11 and 30 post-transplant.
Immunosuppression protocol:
ATG for induction and triple therapy TAC ,MMF and prednisolone for maintenance .
· If no, what are the other options?
Patient wait for suitable donors or Share in PKD or suitable diseased donors.
Excellent
Broad HLA mismatch : 0-2-2 ,Split HLA mismatch : 1-2-2
HLA-A19 broad antigen has HLA-A30&31 as split antigens.
FCM-XM positive for both B & T cells
Positive DSA against both HLA-B58(MFI=8488) and anti-HLA-Bw4(MFI=79
Broad and split antigens :
broad antigen is a serological specificity that is poor or broad compared to other specificities and can be defined as 2 or more split ones..
Split antigen has a more refined or specific cell surface reaction compared with broad one ;eg :
HLA-A23 & HLA-A24 are split antigens of the HLA-A9 broad antigen
HLA-A29,-A30,-A31,-A32,-A33,&-A74 are split antigens of the HLA-A19 broad
antigen.
HLA-B51 & HLA-B52 are split antigens of the HLA-B5 broad antigen HLA-DR15 & HLA-DR16 are split antigens of the HLA-DR2 broad antigen.
HLA-Cw9 & HLA-Cw10 are split antigens of the HLA-Cw3 broad antigens.
Matching for split HLA antigen has better outcome than matching for broad HLA antigens.
At 3 years, there was an 18% difference between the survival rates of grafts with 0 or 4 mm among transplants typed for HLA-A and B antigen splits but difference in transplants typed for broad antigens was only 2%.
Proceeding for Tr
High-level AB to Bw4 (or to Bw6) will preclude transplantation with most of available donors. Patient has high anti-HLA-Bw4(MFI=7959), high DSA against HLA-B54(MFI=8488).He is considered highly sensitized and it is so difficult to proceed to transplantation .
Immunosuppression protocol if proceeding for Tr:
Desensitization with combination of PE and rituximab to reduce the
DSA and achieving negative cross match. Induction can be done with ATG then triple therapy with Tac , MMF, and prednisolone
Another option:
PKD
Combination of PKD and desensitization:
Reference
.Euro transplant Manual© –version 2021 April 14. 20210 – subject to change
Charles T. Lutz.HLA Bw4 and Bw6 Epitopes Recognized by Antibodies and Natural Killer Cells. Curr Opin Organ Transplant. 2014 August ; 19(4): 436–441. doi
Mahendra NM, Miceal C, Aisling C and Jeanie M. HLA Incompatible Successful Renal Transplantation Across Bw4/Bw6 Alleles in Two Patients. Austin Transplant Sci. 2018; 3(1): 1007.
Gerhard Opelz IMPORTANCE OF HLA ANTIGEN SPLITS FOR KIDNEY TRANSPLANT MATCHING. The Lancet. https://doi
Well done but last CX B cell negative. Any suggestions?
.if no, what are the alternatives?
paired kidney donation or
find compitable donor.
references
1)Opelz G. Importance of HLA antigen splits for kidney transplant matching. Lancet. 1988 Jul 9;2(8602):61-4. doi: 10.1016/s0140-6736(88)90001-3. PMID: 2898695.
2) Yacoub R, Nadkarni GN, Cravedi P, He JC, Delaney VB, Kent R, et al. Analysis of OPTN/UNOS registry suggests the number of HLA matches and not mismatches is a stronger independent predictor of kidney transplant survival. Kidney Int. 2018 Feb;93(2):482-490. doi: 10.1016/j.kint.2017.07.016. Epub 2017 Sep 29. PMID: 28965746.
Well done
1-we dont know blood groub of both donor and recepient
broad mismatch 022
spilit mismatch 122 (A19 broad include A30-A31 spilit)
crossmatch positive in T&B cell twice before (anti HLA B AB)
but last time positive t-cell &negativeB cell this may be due to technical error or previous treaeted with retuximab
2-broad AG not specific as it may have subdivided spilit AG that can be detected by high resolution assay so it may be 0 mismatch in broad AG level but 1or 2 mismatch in spilit level that will interfer with graft survival also increase risk of rejection specially in such high risk patient
3-NO
high risk (high DSA 9000MFI) with 5 mismatch(2DR)
5-exchange protocol
Retuximab and monoclonal antibodies can give false positive CX not a negative one as in the above case
However we’ll done.
The prospective recipient is a 57-year-old male (blood group masked) being offered a kidney from a 46-year-old living donor (blood group masked). Hence the blood-group compatibility cannot be commented upon.
The HLA typing of the pair in HLA A B and DR reveals a 022 mismatch on broad antigen typing and a 122 mismatch on split antigen typing. This is because HLA A30 and A31 are split antigen for broad antigen A19.
The report shows a T and B cell flowcytometry cross match (FCXM) with three historical sera of the patient, all of which are positive, except with B cell FCXM which is negative on 15 November 2011. T and B auto FCXM are negative.
A positive T cell crossmatch in presence of a negative B cell crossmatch may be due to either a technical error, or non-HLA antibodies.(1) The mechanisms for a positive T cell and negative B cell crossmatch include differential expression of HLA class I antigen on T cell and B cell as well as differential binding of antibodies to T cells and B cells.(2)
There is presence of DSA: Anti HLA B58 (MFI 8488) and Anti HLA Bw4 (MFI 7959).
HLA B58 is a rare antigen, and Bw4 cross reacts with it (being part of Bw4CREG as per Rodey CREG classification.(3)
A broad antigen is HLA molecule with a poor specificity and it can be divided into 2 or more split antigens having a more refined or specific cell surface reaction than the broad antigen.
As a broad antigen has poor specificity while the split antigens are more specific, a split mismatch will have different response to immune stimulation causing graft injury and rejection leading to poorer outcomes. One of the initial studies assessing split antigen versus broad antigen showed that as compared to broad antigen mismatches, split antigen mismatches had 5 times higher difference in graft survival between 0 and 6 mismatches (31% versus 6%) at 3 years, signifying the importance of split antigen typing in renal transplantation.(4) HLA typing and mismatch determination between the potential transplant recipient and donor pair is an important factor for prognostication in kidney transplantation. Studies have shown that the number of HLA match in the recipient-donor pair is a strong predictor of graft kidney survival.(5) The higher the HLA match, lower the incidence of delayed graft function as well as acute rejection rate in first year and higher the 10-year graft survival.(6,7) HLA mismatches have been shown to be associated with poor transplant outcomes.(8) UNOS registry showed that the risk of renal graft failure increased with the number of mismatches (13% in 1/6 mismatch and 64% in 6/6 mismatch).(9) Increased formation of DSAs is seen in case with Class II HLA mismatch (HLA-DQ, DR) thereby ultimately leading to poor graft survival.(10) Increased risk of death with a functioning kidney graft has been seen in recipients with increased HLA mismatch.(11) So, if we rely only on broad antigen typing, we will not be able to understand the risks involved.
Of note is a study by Su et al which deduced that due to availability of better and more potent immunosuppression, HLA mismatch has lost much of its relevance.(12)
This donor-recipient group has high degree of HLA mismatch (especially 2DR mismatch). Considering a positive crossmatch with presence of DSA, I will not proceed with the transplant directly.
The MCS (Median Channel Shift) for the patient is not given in the report.
For attempting desensitization, MCS should be <250.
The DSA-RIS score for this patient is 10 (5+5), which is less than 17. (13)
If we take up this patient for transplant then the patient will require desensitization with Plasmapheresis and IVIG and rituximab to achieve a negative crossmatch before proceeding with the transplant.
Since this patient is a high immunological risk category patient, the patient will require induction immunosuppression and tacrolimus based triple drug maintenance immunosuppression.(14)
1) Induction therapy: Injection Anti Thymocyte Globulin (ATG) in dose of 1-1.5 mg/kg per day for 4-6 days (total dose 6 mg/kg).
2) Maintenance immunosuppression: Triple drug therapy including
a. Tacrolimus: Target trough level of 8-10 ng/ml
b. Mycophenolate mofetil (MMF): 1000 mg twice a day
c. Corticosteroids: Injection methylprednisolone 500 mg intravenous on the day of surgery, followed by tablet prednisolone 1mg/kg/day for 3 days and then 20 mg/day, to be tapered to 5 mg/day over next 6 to 8 weeks.
Post-transplant, patient requires close follow-up with clinical and laboratory evaluation.(14)
i) Complete blood count, urine examination and serum creatinine.
ii) To look for proteinuria: Spot urine protein-to-creatinine ratio.
iii) DSA testing: Once in first three months, then annually or whenever there is any graft dysfunction, alteration in immunosuppression or suspicion of non-adherence.(15,16)
iv) Protocol biopsy: Once in first three months.(15) If the biopsy shows features of AMR, it should be treated.
In a patient with DSA and positive flowcytometry crossmatch, it is better to change the donor – by either enrolling in a paired-exchange program, or asking for another donor in the family. If no living donor available, the patient can remain on deceased donor waitlist till availability of a compatible donor, although it will be difficult due to the presence of anti HLA-Bw4 antibodies as HLA-Bw4 is very common and these antibodies can cross react with a number of other HLA antigens like A9, 24, 32, B13, 27, 37, 38, 12, 44, 47, 5, 51, 52, 17, 57, 58 and 59.(3)
References:
1) Kumar A, Mohiuddin A, Sharma A, El Kosi M, Halawa A (2017) An Update on Crossmatch Techniques in Transplantation. J Kidney 3: 160. doi:10.4172/2472-1220.1000160
2) Putheti P, Sharma VK, Friedlander R, Menon A, Dadhania D, Muthukumar T, Suthanthiran M. T-Cell-Positive, B-Cell-Negative Flow Cytometry Crossmatch: Frequency, HLA Locus Specificity, and Mechanisms Among 3073 Clinical Flow Cytometry Crossmatch Tests. Exp Clin Transplant. 2022 Feb;20(2):180-189. doi: 10.6002/ect.2021.0334. Epub 2022 Jan 3. PMID: 34981713.
3) Wade JA, Hurley CK, Takemoto SK, Thompson J, Davies SM, Fuller TC, Rodey G, Confer DL, Noreen H, Haagenson M, Kan F, Klein J, Eapen M, Spellman S, Kollman C. HLA mismatching within or outside of cross-reactive groups (CREGs) is associated with similar outcomes after unrelated hematopoietic stem cell transplantation. Blood. 2007 May 1;109(9):4064-70. doi: 10.1182/blood-2006-06-032193. Epub 2007 Jan 3. PMID: 17202313; PMCID: PMC1874562.
4) Opelz G. Importance of HLA antigen splits for kidney transplant matching. Lancet. 1988 Jul 9;2(8602):61-4. doi: 10.1016/s0140-6736(88)90001-3. PMID: 2898695.
5) Yacoub R, Nadkarni GN, Cravedi P, He JC, Delaney VB, Kent R, et al. Analysis of OPTN/UNOS registry suggests the number of HLA matches and not mismatches is a stronger independent predictor of kidney transplant survival. Kidney Int. 2018 Feb;93(2):482-490. doi: 10.1016/j.kint.2017.07.016. Epub 2017 Sep 29. PMID: 28965746.
6) Takemoto SK, Terasaki PI, Gjertson DW, Cecka JM. Twelve years’ experience with national sharing of HLA-matched cadaveric kidneys for transplantation. N Engl J Med. 2000 Oct 12;343(15):1078-84. doi: 10.1056/NEJM200010123431504. PMID: 11027742.
7) Wissing KM, Fomegné G, Broeders N, Ghisdal L, Hoang AD, Mikhalski D, et al. HLA mismatches remain risk factors for acute kidney allograft rejection in patients receiving quadruple immunosuppression with anti-interleukin-2 receptor antibodies. Transplantation. 2008 Feb 15;85(3):411-6. doi: 10.1097/TP.0b013e31816349b5. PMID: 18322434.
8) Shi X, Lv J, Han W, Zhong X, Xie X, Su B, et al. What is the impact of human leukocyte antigen mismatching on graft survival and mortality in renal transplantation? A meta-analysis of 23 cohort studies involving 486,608 recipients. BMC Nephrol. 2018 May 18;19(1):116. doi: 10.1186/s12882-018-0908-3. PMID: 29776389; PMCID: PMC5960106.
9) Williams RC, Opelz G, McGarvey CJ, Weil EJ, Chakkera HA. The Risk of Transplant Failure With HLA Mismatch in First Adult Kidney Allografts From Deceased Donors. Transplantation. 2016 May;100(5):1094-102. doi: 10.1097/TP.0000000000001115. PMID: 26901078; PMCID: PMC8086563.
10) Wiebe C, Gibson IW, Blydt-Hansen TD, Karpinski M, Ho J, Storsley LJ, et al. Evolution and clinical pathologic correlations of de novo donor-specific HLA antibody post kidney transplant. Am J Transplant. 2012 May;12(5):1157-67. doi: 10.1111/j.1600-6143.2012.04013.x. Epub 2012 Mar 19. PMID: 22429309.
11) Opelz G, Döhler B. Association of HLA mismatch with death with a functioning graft after kidney transplantation: a collaborative transplant study report. Am J Transplant. 2012 Nov;12(11):3031-8. doi: 10.1111/j.1600-6143.2012.04226.x. Epub 2012 Aug 17. PMID: 22900931.
12) Su X, Zenios SA, Chakkera H, Milford EL, Chertow GM. Diminishing significance of HLA matching in kidney transplantation. Am J Transplant. 2004 Sep;4(9):1501-8. doi: 10.1111/j.1600-6143.2004.00535.x. PMID: 15307838.
13) Sethi S, Choi J, Toyoda M, Vo A, Peng A, Jordan SC. Desensitization: Overcoming the Immunologic Barriers to Transplantation. J Immunol Res. 2017;2017:6804678. doi: 10.1155/2017/6804678. Epub 2017 Jan 3. PMID: 28127571; PMCID: PMC5239985.
14) Kidney Disease: Improving Global Outcomes (KDIGO) Transplant Work Group. KDIGO clinical practice guideline for the care of kidney transplant recipients. Am J Transplant. 2009 Nov;9 Suppl 3:S1-155. doi: 10.1111/j.1600-6143.2009.02834.x. PMID: 19845597.
15) Tait BD, Süsal C, Gebel HM, Nickerson PW, Zachary AA, Claas FH, et al. Consensus guidelines on the testing and clinical management issues associated with HLA and non-HLA antibodies in transplantation. Transplantation. 2013 Jan 15;95(1):19-47. doi: 10.1097/TP.0b013e31827a19cc. PMID: 23238534.
16) Crespo M, Zárraga S, Alonso Á, Beneyto I, Díaz Corte C, Fernandez Rodriguez AM, et al; GREAT Study Group and Spanish Network for Research in Renal Diseases (REDINREN, RED16/0009). Monitoring of Donor-specific Anti-HLA Antibodies and Management of Immunosuppression in Kidney Transplant Recipients: An Evidence-based Expert Paper. Transplantation. 2020 Aug;104(8 Suppl 2):S1-S12. doi: 10.1097/TP.0000000000003270. PMID: 32658025.
Excellent Amit and good you did not mention that monoclonal antibodies or Retuximab are the cause of B cell negative cross match as lots of the students mentioned!,
Please comment on the HLA match and the crossmatch results shown below
1- Broad antigen mismatch 012
As HLA A30 and 31 are both splits of the braod HLA A 19
HLA B41 is a rare antigen and compensated for HLA B 41
Split mismatch is 112
Historic B and T cell FCXM were positive indicating anti bodies against either HLA class I or both class I and II
Current FCXM is positive for T cells only either
– Non HLA antibodies
– Previuos treatment with rituximab
– Technical error
Negative auto crossmatch excluding the presence of autoantibodies
Significant level of DSA against both HLA B58 with 8488 MFI and HLA Bw4 with 7959 MFI (HLA Bw4 is a cross reactive epitope that can bind several antigens sharing the same public epitope)
No , thisis a high risk transplantation due to degree of HLA mismatch ( including 100% Dr mismatch) and presence of significant level of preformed DSA
1- Pretransplantation desensitization till obtain negative FCXM with PE nad IVIG
2- Induction with ATG
3- Maintinance with triple IS ( steroid, CNI , MMF)
4- Maintain trough level of IS at high therapeutic level
5- Regular monitoring of DSA and consider protocol biopsy
– Paired kidney donation
– Remain on waiting list for more suitable donor
Monoclonal antibodies can cause false positive CX and not false negative
T cellCX positive in the above case has many reasons as DSAs and BW4
Otherwise fine
HLA-A,B,DR broad antigen mismatch 022 while split antigen mismatch is 122
HLA-A19 is a broad antigen with HLA-A 30 and 31 are split antigens
Historic B cell and T cell FCXM were positive
Current serum showing positive T cell FCXM and negative B cell FCXM which may indicate HLA class I antigen with more expression on T lymphocytes, DSA with impaired reaction to B cell or technical error
Current B cell FCXM negative with positive historic may suggest previous antibodies that decreased in titer but still at risk of antibody production by specific memory B cells when re-exposed
Auto crossmatch is negative excluding presence of autoantibodies
DSA anti-HLA B58 with 8488 MFI and anti-HLA Bw4 with 7959 MFI (anti-HLA Bw4 is cross reactive epitope group and can bind to several antigens sharing the same public epitope including B58 that is present in the donor)
HLA typing can be done for broad antigen specificities or for their subunit antigen splits
as HLA-A19 is a broad antigen with several splits including HLA-A30 and 31
HLA typing at level of split antigens shows better correlation with graft survival than broad antigens.
No, as it carries high immunological risk due to HLA mismatch 5/6 including 2 HLA-DR mismatches, positive T cell FCXM historic and current, current B cell FCXM is negative with positive historic B cell FCXM, presence of DSA to class I with MFI>5000
Desensitization with plasmapheresis and IVIG till have negative FCXM
Induction with ATG as high immunological risk
Triple maintenance therapy with tacrolimus, MMF and prednisolone
Kidney paired donation or remaining on deceased donor waiting list
Pratschke J, Dragun D, Hauser IA, Horn S, Mueller TF, Schemmer P, Thaiss F. Immunological risk assessment: The key to individualized immunosuppression after kidney transplantation. Transplantation Reviews. 2016 Apr 1;30(2):77-84.
Konvalinka A, Tinckam K. Utility of HLA antibody testing in kidney transplantation. Journal of the American Society of Nephrology. 2015 Jul 1;26(7):1489-502.
Opelz G, STUDY FT. Importance of HLA antigen splits for kidney transplant matching. The Lancet. 1988 Jul 9;332(8602):61-4.
Excellent
Histocompatibility and immunogenicity report of related pair for KTX.
ABO matching not illustrated here.
HLA matching:
-Broad 0,2,2 mismatch(as A30 and A 31 are considered splits antigen for A19).
-Split 1,2.2 mismatch.
Cross-match:
Positive T and B cell FCXM with negative auto cross-match with historical report of negative B cell CM which may be due to technical error, prozone effect, treatment with monoclonal ABS like rituximab, autoimmune disease like SLE, non-HLA antibodies .
DSA:
There is DSA against HLA class I (B58 with MFI 8488) and to the public epitope Bw4 (B58 is one of the Bw4 group).
Which Shared by many HLA antigens and can cause cross reactivities by a single anti HLA antibody.(1).
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation?
Split antigen mean that has a more refined or specific cell surface reaction relative to a broad antigen.(Example: HLA-B51 and HLA-B52 are split antigens of HLA-B5).
HLA antigen “splits” results in better transplant outcome than matching for “broad” HLA antigens was investigated in 30 000 first cadaver kidney transplants(2).
Will you proceed with the direct transplantation?
NO,
Highly sensitized with high risk of hyper acute rejection.
High mismatch for broad and split antigens.
DSA positive with high MFI with public epitope which keep the recipient highly sensitized to many antibodies.
If yes, what is your immunosuppression protocol.
Desensitization with PEx and high dose IVIg + or – Rituximab.
Once CM being negative we can transplant with basiliximab as induction with Tacrolimus based triple therapy.
With following DSA and protocol biopsy.
If no, what are the alternatives?
PKD which is preferred here.
References:
1-El-Awar N, Jucaud V, Nguyen A. HLA Epitopes: The Targets of Monoclonal and Alloantibodies Defined. J Immunol Res. 2017;2017:3406230. doi:10.1155/2017/3406230.
2-Opelz G. Importance of HLA antigen splits for kidney transplant matching. Lancet. 1988 Jul 9;2(8602):61-4. doi: 10.1016/s0140-6736(88)90001-3. PMID: 2898695.
Very good
HLA typing for the patient and his potential testing using the molecular typing method.
There is 022 mismatching (broad) and 122 mismatching (split) as HLA-A31 and HLA-A30 are the splits of HLA-A19.
Crossmatching is done by flow cytometry method and shows a positive T cell CXM repeatedly and negative B cells CXM on the final result while the previous results were positive. The negative B cell CXM can be explained by the fact that the MCS of B cells treated with normal control serum is significantly higher than the MCS of T cells treated with normal control serum and this will lead to T+B- FCXM result.
Negative auto CXM for both B & T cells all over.
There is a DSA against HLA-B58 with MFI of 8488 and another DSA against HLA-Bw4 with MFI of 7959. The Bw4 is an epitope present on HLA-B58.
HLA-Bw4 and HLA-Bw6 are mutually exclusive epitopes associated with all HLA-B antigens, however, certain HLA-A ( 23, 24, 25, 32) and HLA-C ( 1, 3, 7, 8, 9, 10, 12, 14, 16:1) antigens also bear the HLA-Bw4, HLA-Bw6 epitopes respectively.
Bw4 is a public epitope with high immunogenicity and a high-level patient antibody to it will preclude transplantation. 1,2
In a retrospective study that was done to determine the association between HLA-Bw4,6 mismatch and graft outcome, the authors found that Bw4,6 mismatch alone is not associated with poor graft outcome despite their strong immunogenicity and a load of epitope mismatches above a certain threshold is likely required to cause clinical consequences.3
Due to the advances in HLA typing, a group of HLA antigens which were previously considered broad antigens now they can be distinguished as split antigens.
The higher split mismatching is associated with poor graft outcomes.
No, there is a positive T cell CXM ( no information about the MCS), High-level DSA class I, and a high degree of HLA mismatching, no information is given about their blood groups and the cPRA.
First, we need to desensitize the patient to get a negative CXM and to lower the level of DSA to a less risky one using PP+ IVIG + Rituximab.
Induction with ATG 1.5 mg/kg + MP pulse for 3-5 days
maintenance treatment with Tac, MMF, and steroids with monitoring of DSA level and protocol biopsy.
PKD or listing him for the deceased donation program.
References:
Excellent, thank you
Thanks
Please comment on the HLA match and the crossmatch results shown below.
-There are HLA mismatches at A, B, DR :
Broad mismatches: 0.2.2 (A 30 and A31 are split of A 19)
Split mismatches:1.2.2
-Crossmatch:2 historical T and B FC were positive while the last one is only T cell FC positive while B cell FC was negative which may be to a technical error.
-T and B auto FC were negative.
What is meant by broad and split antigens and how do their mismatches affect the outcome of the transplantation?
-The split antigen is split of broad antigens into two or more, eg, A9 split into A23 and A24 and HLA A19 split into A30, A31, A32, and A33, which has a more specific or refined cell surface reaction relative to the broad antigen.
-Split HLA antigens matching is precise and has a better graft survival and transplant outcome than a broad HLA antigen matching.
Will you proceed with the direct transplantation?
-No, I will not proceed with the direct transplantation because:
-Tcell FC is a contraindication for transplantation, so we need to repeat it.
– I will do CDC.
-There is DSA for HLA- B 58 and Bw4.Bw4 is a public antigen whose DSA can cross-reactive with many antigens.
-Check MCS ,if MCS˃250, do not proceed for transplantation.
If yes, what is your immunosuppression protocol?
-The relative intensity score (RIS) is 10.
-Desensitization by: plasma exchange +IVig and rituximab
-Induction by ATG.
-maintenance immunosuppression:Tac, MMF, Prednisolone.
If not, what are the alternatives?
-Search for another living compatible donor
– deceased compatible donor.
– Kidney Paired Donation
Very good
Please comment on the HLA match and the crossmatch results shown below.
No information about the ABO compatibility
this offer from living donor with HLA mismatch in two digit low resolution assay assay with broad mismatch 022 and split mismatch of 122, positive DSA class1 in the last test in November with high titer of > 5000 for donor private DSA B58 and Bw4 which is public antigen can cross-react with many antigens including the donor B58 antigen ,so two HLA-DR mismatch with B split antigen mismatch with cross reactivity associated with high risk of rejection and poor graft outcome.
No CDCXM available but Historic positive T, B cell FCXM but auto FXM was persistently negative and the most recent FCXM only T cells positive indicate true positive T cell provide positive DSA for class1 with significantly high titer more than 5000 Previous positive B cells may indicate technical error, prozone effect, treatment with monoclonal ABS like rituximab, autoimmune disease like SLE, non-HLA antibodies
This offer from living donor still we can do CDCXM as well which is likely will be positive with such high DSA level in class 1 in that case positive T cells CDCXM and positive FXCM with high DSA better to avoid this donor as he is high risk for hyper-acute or accelerated acute rejection
What is meant by broad and split antigens and how their mismatches affect the outcome of the transplantation? In highly sensitized recipient like this patient better to go for high resolution molecular genetic assay with more specific split and epilate match to avoid cross reactivity
Split antigen matching more specific and associated with better graft outcome
Will you proceed for the direct transplantation?
No better to avoid he is highly sensitized recipient with historic and current positive FCXM including T and B cells with preformed DSA positive to class 1 with high titer > 5000, no details about the MCS if its more than 250 then definitely will reject this donor and list him on KPD or DD waiting list
If yes, what is your immunosuppression protocol
Desensitization to shift the FCXM to negative and lower DSA level ,desensitization with plasmapheresis 3-5 session 10-12 days prior to transplant date with IVIG high dose 2gm / kg followed by induction with ATG 1.5mg / kg for 4 doses and PMP 500mg intraoperative followed followed by maintenance IS with tacrolimus based IS and full dose MMF with prednisolone with close monitoring of DSA level by uminex SAB day 4 2, 4 , 8 wks post transplant with graft biopsy once indicated or protocol biopsy based on center policy , proteinuria level and target tacrolimus trough of 8-10ng in the first 6 months post transplant
If no, what are the alternatives?
Paired kidney donation, DD waiting list
References:
1- kidney transplantation handbook 6th edition.
2- Moszkowska G, Zielińska H, Zieliński M, Gołębiewska J, Bzoma B, Sakowska J, Dębska-Ślizień A, Trzonkowski P. The utility of cytolytic flow cytometry crossmatch before kidney transplantation. Transpl Immunol. 2021 Oct; 68:101426.
3-Improved flow cytometry cross-matching in kidney transplantation.
4- kidney transplantation in adults :overview of HLA sensitization and crossmatch testing
up to date medicine 2022.
Thank you, well done