HLA-DPB1 molecular mismatches are risk factors for acute rejection and low 5-year graft function in first kidney transplants.

INTRODUCTION
The study aimed to investigate the impact of HLA-DPB1 allelic and molecular mismatches on the occurrence of acute rejection (AR) and low 5-year graft function (5Y-GF) in first kidney transplant (KT) recipients.


METHOD
This is a single center retrospective study of 130 deceased donor KT recipients transplanted between 2014 and 2016. HLA-DPB1 allelic MM and the following molecular MM (mMM) were analyzed: expression MM with the high expression G allele in the donor; T cell epitope MM (TCE MM); epitope MM (EMM), considering all six hypervariable regions (EMM-ABCDEF HVR), or only ABEF regions (EMM-ABEF HVR); eplet MM (EpMM); antibody-verified eplet MM (AbVer EpMM); and solvent accessible amino acid MM (SAMM).


RESULTS
There was no association of allelic MM with AR or 5Y-GF. The variables independently associated (Cox regression analyses) with AR were high donor final creatinine, non-permissive TCE MM, ABCDEF EMM load ≥ 6, EpMM load ≥ 6; SAMM load ≥ 5, and AbVer EpMM load ≥ 3. No association between any HLA-DPB1 mMM and 5Y-GF was observed when all 130 transplant recipients were considered. However, when transplants from expanded criteria donors were excluded, independent associations were detected (logistic regression analyses) with AbVerEpMM load ≥ 2, SAMM load ≥ 7, cerebro-vascular death, donor age, and AR.


CONCLUSION
To our knowledge, this is the first study that shows that some HLA-DPB1 mMM are associated with AR and low 5Y-GF in a population of exclusively first kidney transplant recipients. This article is protected by copyright. All rights reserved.