【Background】 We calculated donor-recipient Eplet mismatch (EpMM) based on HLA class II genotyping results (DRB1, DPB1, DQB1) and retrospectively investigated the relationship between prognosis and renal transplant prognosis.

【Methods】 The subjects consisted of 273 patients who underwent renal transplantation at our hospital and were genotyped for the six antigens of HLA-A, B, C, DR, DP, and DQ. Epitope mismatch (antibody validated) were calculated using HLA Matchmaker. The analysis was performed by dividing the subjects into 6 groups: Group 1 (G1) (0<EpMM>2), Group 2 (G2) (3<EpMM>5), Group 3 (G3) (6<EpMM>8), Group 4 (G4) (9<EpMM>11), Group 5 (G5) (12<EpMM>14), and Group 6 (G6) (15≤EpMM).

【Results】 The average EpMM was 7.2. Group 3 has the most, accounting for 32%. It has been suggested that there is a close relationship between EpMM and the incidence of CAMR and dnDSA. CAMR was observed in 33.3% of G6 and 6.3% of G1. The incidence of dnDSA was 41.7% in G6 and 12.5% in G1. However, the eGFR was not significantly different between G1 and G6 up to 10 years after transplantation.

【Conclusion】 The results of this study show that as EpMM increases, the incidence of CAMR and dnDSA increases. Our findings suggest that patients with an HLA-DPB1, DQB1, or DRB1 EpMM of 6 or higher are at increased risk.