All patients were to receive either peripheral blood or bone marrow allo-HSCT for hematologic malignancy from unrelated donors who were 8 of 8 or 7 of 8 human leukocyte antigen (HLA)-matched (a single allele mismatch at HLA-A, HLA-B and HLA-C, and HLA-DRB1 was permitted). This evidence concerns the gene HLA-DRB1 and hematologic disorder.