ABSTRACT
Attempts at transplantation of bone marrow to correct hematological abnormalities were first reported in the 1930s (1), although successful outcomes of this procedure did not occur until the late 1960s, largely as a result of understanding the importance of human leukocyte antigen (HLA) typing (2,3). For two decades, allogeneic hematopoietic stem cell transplantation was largely confined to patients with healthy HLA-identical-related donors, usually siblings. With the development of the National Marrow Donor Program (NMDP) in the 1980s, patients lacking family donors were sometimes able to undergo bone marrow transplantation from histocompatible unrelated-volunteer donors (4-5), although many other patients still did not have suitable unrelated bone marrow donors identified through the NMDP or other registries (6).
