Survival of Nationally Shared, HLA-Matched Kidney Transplants from Cadaveric Donors

BACKGROUND: The importance of HLA histocompatibility typing to the outcome of transplantation of cadaveric kidneys has been controversial. Four years ago, a prospective trial began in all U.S. transplantation centers to determine whether the results of transplantation would improve with the nationwide shipment of kidneys from cadaveric donors to waiting patients undergoing dialysis when there was a match at the HLA-A, B, and DR loci. METHODS: A total of 1386 cadaveric kidneys were shipped from 108 organ centers to 198 transplantation centers and distributed among HLA-matched recipients, 1004 of whom were receiving a first transplant and 382 of whom were receiving a subsequent transplant. Graft survival in these recipients was compared with that in 22,188 recipients of first transplants and 3950 recipients of subsequent transplants whose HLA antigens differed from those of the donor. RESULTS: The rate of graft survival at one year in recipients of HLA-matched first transplants was 88 percent, as compared with 79 percent in the recipients of mismatched grafts (P less than 0.001). The estimated half-life of the kidney after the first year was 17.3 years for matched grafts, as compared with 7.8 years for mismatched grafts (P = 0.003). Among paired kidneys from 470 donors, one-year graft survival was 87 percent in the recipients of matched first grafts, as compared with 80 percent in the recipients of the contralateral kidneys, who did not have HLA matches with the donors. In donors and recipients matched for the more highly defined split Class I and Class II HLA antigens, the rate of graft survival after one year was as high as 90 percent. CONCLUSIONS: The collaborative renal-transplantation program for HLA matching of donors and recipients yielded an increased rate of one-year graft survival and an estimated half-life for matched grafts twice that for mismatched grafts. An increased role for HLA matching in kidney allocation is therefore indicated.