Role of minor histocompatibility antigens in renal transplantation.

In hematopoietic stem cell transplantation (HSCT), disparities between recipients and donors for minor histocompatibility antigens (mHags) have been shown to be related to graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) effects. We investigated the effect of mHag mismatches on kidney allograft survival. Out of 33 785 kidney transplants on which DNA and clinical data were available to the Collaborative Transplant Study (CTS), 702 recipient/donor pairs could be identified as HLA-A, -B and -DRB1 matched first transplants of Caucasian origin. These pairs were typed for genetic polymorphisms of the mHags HA-1, HA-2, HA-3, HA-8, HB-1, ACC-1 and UGT2B17. Because mHags are presented in an HLA-restricted manner, only HLA-A*02 positive pairs were included in the analysis of HA-1, HA-2 and HA-8. Similarly, only HLA-A*01, HLA-B*44 and HLA-A*24 positive pairs were considered for the evaluation of HA-3, HB-1 and ACC-1, respectively, whereas UGT2B17 compatible transplants were assessed in HLA-A*29 and HLA-B*44 positive pairs. None of the mHag disparities showed a statistically significant effect on death-censored 5-year graft survival. This report represents the first large-scale study on the relevance of mHags in kidney transplantation.