Korean J Transplant.  2023 Nov;37(Suppl 1):S17. 10.4285/ATW2023.F-5823.

Immunologic risk stratification of kidney transplant recipients by combining human leukocyte antigen-eplet mismatch and PIRCHE-II

• Lee D
• Kim BC
• Choi SH
• Kim J

• KMID: 2551591
• DOI: http://doi.org/10.4285/ATW2023.F-5823

Abstract

Background
Although limiting the number of human leukocyte antigen (HLA) mismatches between donor and recipient is an effective method to reduce the risk of kidney allograft rejection, this approach has some limitations. Several algorithms have been developed, aiming to predict alloimmune reactivity. HLA matchmaker and PIRCHE-II (Predicted Indirectly ReCognizable HLA Epitopes) algorithms are promising solutions to estimate alloreactivity risk after kidney transplantation
Methods
We examined 200 kidney transplant recipients from 2001 to 2023. The primary purpose of our study was to verify whether a combination of HLA-eplet mismatching (MM) and PIRCHE-II algorithms can improve risk stratification of kidney transplantation. The second purpose was to evaluate whether a nadir of Tacrolimus concentration or intrapatient variability is associated with the development of de novo donor-specific antibody, acute rejection, chronic antibody-mediated rejection (ABMR), and graft failure regarding high HLA-eplet MM or high PIRCHE-II.
Results
PPIRCHE-II or total eplet MM alone was insufficient to predict graft failure. When each of them was combined with IPV or a nadir of tacrolimus concentration, the high/high group had a statistically significantly higher risk of allograft failure than that of the low/low group respectively. High-PIRCHE/high-eplet MM group had significantly the highest risk of graft failure compared with the other three groups. Independent predictors of graft failure on multivariate analysis were chronic ABMR, and the low nadir of tacrolimus trough level.
Conclusions
HLA-total eplet MM cut-offs alone did not predict the risk of graft failure, however, if used in combination with PIRCHE-II. We demonstrated that high-PIRCHE and total eplet MM group is significantly the worst graft outcome compared with high-/low-, low-/high-, and low-/low- PIRCHE and eplet MMs, respectively. Together with HLA-eplet MM, The PIRCHE-II algorithm can provide a better estimated alloreactive risk for individual patients and eventually an improved allograft kidney survival.