EFFECT OF MATCHING OF CLASS I HLA ALLELES ON CLINICAL OUTCOME AFTER TRANSPLANTATION OF HEMATOPOIETIC STEM CELLS FROM AN UNRELATED DONOR

Background The requirements with respect to HLA compatibility and the relative importance of matching for individual class I and class II HLA alleles in the transplantation of hematopoietic stem cells from unrelated donors have not yet been established. Methods We performed retrospective DNA typing of alleles at 11 polymorphic loci of HLA genes in 440 recipients of hematopoietic stem cells from unrelated donors who were serologically identical with their respective recipients for HLA-A, B, and DR antigens. Of these recipients, 80 percent had leukemia; the rest had lymphoma, marrow failure, or a congenital disorder. Results Multivariate analysis showed that incompatibility for HLA-A alleles and incompatibility for HLA-C alleles were independent risk factors for severe acute graft-versus-host disease (GVHD) (HLA-A, P=0.006; HLA-C, P=0.001). Mismatching of HLA-A, but not of HLA-C, alleles was an independent risk factor for death (P<0.001). Mismatching of HLA-C alleles was a significant risk factor for relaps...