Non-inherited maternal HLA antigens and protection against sensitisation.

To test the hypothesis that non-inherited maternal antigens (NIMAs), which reportedly afford protection against sensitisation by random transfusions, can provide protection against repetitive antigenic exposure of donor-specific transfusion (DST), 140 DST patients whose donors were mismatched for NIMAs and 71 whose donors were mismatched for non-inherited paternal antigens (NIPAs) were studied. The rate of sensitisation in the two groups of patients was similar (22.1% vs 15.5%). There was no difference in sensitisation to NIMAs and NIPAs between patients who received azathioprine and those who did not. The formation of donor specific HLA antibody was comparable in the two groups. After kidney transplantation there were no differences in 1-year graft survival or the incidence of rejection episodes. These findings suggest that NIMAs do not provide lifelong protection against subsequent repetitive antigen challenge and sensitisation.