Effect of one-HLA-DR-antigen-matched and completely HLA-DR-mismatched blood transfusions on survival of heart and kidney allografts.

Blood transfusions can influence the survival of organ allografts favorably, in spite of the danger of sensitization. We investigated the influence of HLA compatibility between blood donors and transfusion recipients on the production of HLA antibodies and on graft survival. Among recipients of transfusions who shared one HLA-DR antigen with their respective donors, antibodies developed in 6 of 28 who had received one transfusion, in 2 of 16 who had received three transfusions, and in 4 of 24 who had undergone renal transplantation. Among recipients who were mismatched with their donors for both HLA-DR antigens, the rate of sensitization was significantly higher in all three of these groups (18 of 30, P = 0.02; 12 of 16, P = 0.0007; and 12 of 22, P = 0.001). The survival of kidney allografts among graft recipients who were given transfusions and shared one HLA-DR antigen with their blood donors (81 percent at five years) was significantly higher than among recipients who were given transfusions and were mismatched for both HLA-DR antigens (57 percent; P = 0.02) or among recipients who were not given transfusions (45 percent; P = 0.001). There was no difference in graft survival between patients who received transfusions mismatched for two HLA-DR antigens and those who were not given transfusions. We conclude that allograft survival can be improved by pretransplantation blood transfusion when the transfusion recipients share at least one HLA-DR antigen with their donors. In view of the increased rate of sensitization and the lack of improvement in graft survival, the transfusion of blood mismatched for two HLA-DR antigens appears to be contraindicated in candidates for transplantation.