HLA-DR matching in multicenter, single-typing laboratory data.

The results of 370 transplants done at 11 transplant centers in Los Angeles over the past 4 years is summarized for DR matching and transfusions. Among 28 patients with two HLA-DR antigens matched, the 1-year transplant survival rate was 75% as compared with 47% for those patients with no matched HLA-DR antigen (P less than 0.0025). Therefore, in this multicenter single-typing laboratory trial, HLA-DR typing had a significant effect on transplant outcome. The effect of pretransplant transfusions was additive. Patients with fewer than five transfusions had a 1-year survival rate of 45% compared with 69% for those with five or more transfusions (P less than 0.0005). In patients with two DR antigens matched and five or more transfusions, the survival rate was 86%. Similarly, patients with zero or one DR antigen match had a higher graft survival rate if they had previously been transfused with more than four units of blood. We conclude that two-DR antigen-matched transplants have a higher change of success than those with a zero or one antigen match and that this effect is additive with transfusions.