Dominant effect of histocompatibility on ten-year kidney transplant survival

Using actuarial methods, factors influencing long-term graft survival were examined in 33,594 recent (since 1974) kidney transplants reported to the University of California, Los Angeles, Transplant Registry. One- and 10-year graft-survival rates as well as late (from 3 through 10 years) graft-loss rates (half-lives) were determined. The donor-recipient relationship had the greatest influence on long-term graft survival. Transplants between HLA-identical siblings had graft-survival rates of 89% at 1 year and 68% at 10 years, compared with 76% and 43% for parental donors, and 58% and 26% for cadaver donor transplants, respectively. These differences were also evident from the graft half-lives, which were 22 years for HLA-identical sibling, 12 years for parental, and 8 years for cadaver donor allografts. In cadaver donor transplants, matching for HLA-A,B antigens had the greatest influence on long-term graft survival, with a 15% 10-year graft survival (39% vs. 24%) and 7-year half-life (14 vs. 7 years) advantage seen with the best (zero HLA-A,B mismatches) compared with the worst (4 HLA-A,B) cases, respectively. Some of the factors studied, such as transplant number and pretransplant transfusions, tended to influence the short- rather than long-term graft-survival rates. Others, including HLA-A,B matching, early graft function and the recipient's original disease, influenced both early and late graft survival. Over all, histocompatibility between donor and recipient had by far the greatest influence on the long-term success of renal allografts.