Lack of influence of donor-recipient differences in subtypic HLA-A,B antigens (splits) on the outcome of cadaver renal transplantation.

Data collected prospectively on 3811 cadaver renal transplants performed between June 1977 and July 1982 by the 42 member institutions of the South-Eastern Organ Procurement Foundation (SEOPF) were analyzed to determine whether donor-recipient differences in sub-typic HLA-A,B specialties (splits) influenced outcome. The number of HLA-A,B antigens matched and mismatched between each donor and recipient was calculated in three ways: (1) considering all antigens and splits as distinct (not matched); (2) considering all splits as only matched with their corresponding typic antigen (but not with each other); and (3) considering all splits as matched with both their corresponding typic antigen as well as each other. Overall graft survival, graft loss from irreversible rejection, and patient survival stratified by the level of HLA match were the same using all three methods. In addition, using multivariate Cox regression analysis, the strong association between good HLA matching and increased graft survival was the same using all three methods of matching. Patients with a given number of mismatched antigens had no significant decrease in survival when additional splits were considered mismatched with each other or their corresponding typic antigen. These results suggest that matching of typic HLA-A,B antigens plays a highly significant role in reducing graft rejection but that donor-recipient differences in splits have a negligible effect on graft outcome.