An Integrated Approach Using HLAMatchmaker and Pirche II for Epitopic Matching in Pediatric Kidney Transplant-A Romanian Single-Center Study

(1) Background: Renal transplantation (KT) is the most efficient treatment for chronic kidney disease among pediatric patients. Antigenic matching and epitopic load should be the main criteria for choosing a renal graft in pediatric transplantation. Our study aims to compare the integration of new histocompatibility predictive algorithms with classical human leukocyte antigen (HLA) matching regarding different types of pediatric renal transplants. (2) Methods: We categorized our cohort of pediatric patients depending on their risk level, type of donor and type of transplantation, delving into discussions surrounding their mismatching values in relation to both the human leukocyte antigen Matchmaker software (versions 4.0. and 3.1.) and the most recent version of the predicted indirectly identifiable HLA epitopes (PIRCHE) II score. (3) Results: We determined that the higher the antigen mismatch, the higher the epitopic load for both algorithms. The HLAMatchmaker algorithm reveals a noticeable difference in eplet load between living and deceased donors, whereas PIRCHE II does not show the same distinction. Dialysis recipients have a higher count of eplet mismatches, which demonstrates a significant difference according to the transplantation type. Our results are similar to those of four similar studies available in the current literature. (4) Conclusions: We suggest that an integrated data approach employing PIRCHE II and HLAMatchmaker algorithms better predicts histocompatibility in KT than classical HLA matching.

Eplet mismatch scores and de novo donor-specific antibody development in simultaneous pancreas-kidney transplantation

Antibody-mediated rejection is the principal cause of allotransplant graft failure. Available studies differ on the impact of de novo donor specific antibody (dnDSA) in pancreas transplants but are limited by patient sample size and sera sample collection. High-resolution HLA incompatibility scoring algorithms are able to more accurately predict dnDSA development. We hypothesized that HLA incompatibility scores as determined by the HLA-Matchmaker, HLA-EMMA, and PIRCHE-II algorithms would serve as a predictor of de novo donor specific antibody (dnDSA) development and clarify the role dnDSA as detrimental to simultaneous pancreas-kidney graft survival. Our results show that female sex and race were significantly associated with dnDSA development and dnDSA development resulted in worse kidney and pancreas graft survival. The majority of individuals who developed dnDSA (88%), developed anti-HLA-DQ antibody in some combination with anti-HLA class I or -DR. A multivariate analysis of the incompatibility scores showed that both HLA-Matchmaker and PIRCHE-II scores predicted anti-DQ dnDSA development. An optimal cutoff threshold for incompatibility matching was obtained for these scores and demonstrated statistical significance when predicting freedom from anti-DQ DSA development. In conclusion, increased scores from high-resolution HLA matching predict dnDSA development, and dnDSA is associated with antibody-mediated rejection and worse pancreas and kidney graft outcomes.