Association of MB compatibility with successful intrafamilial kidney transplantation.

The MB system is a newly defined system of B-cell alloantigens closely associated with HLA-DR. We assessed the role of MB compatibility in renal transplantation in a retrospective study of 21 patients who had received a kidney transplant from a related donor matched for a single HLA haplotype. One-year transplant survival was closely correlated with the presence of a compatibile MB antigen in the unshared haplotype of the donor: Eight of eight rejected kidneys were obtained from MB-incompatible donors, and 12 of 13 successful transplants were from MB-compatible donors. The association between MB compatibility and allograft acceptance was highly significant (P = 4.4 x 10(-5)), but no significant relation could be demonstrated between transplant survival and donor-recipient compatibility for antigens of the HLA-A, B or DR loci. These findings suggest that match matching for MB may be critical for the selection of donors in intrafamilial kidney transplantation.