Stem cell transplantation for aplastic anemia.

Survival of patients with aplastic anemia treated with transplantation of bone marrow has improved significantly over the past several decades. Allogeneic bone marrow transplantation (BMT) for patients with HLA-identical siblings is now the first-line therapy, and long-term survival of approximately 90% can be expected with cyclophosphamide/antithymocyte globulin conditioning and postgrafting methotrexate/cyclosporine immunosuppression. The outcome of unrelated donor BMT has also improved significantly with the identification of a preparative regimen with less toxicity combined with the development of high-resolution DNA-based HLA typing to identify the optimal unrelated marrow donor. Patients with fully HLA-matched unrelated donors should be considered candidates for transplantation prior to exposure to repeat courses of immunosuppression. Future progress in hematopoietic stem cell transplantation for aplastic anemia will be directed toward further decreasing the acute toxicity and decreasing the delayed effects of the conditioning regimens while maintaining highly reliable rates of sustained engraftment with prevention of acute and chronic graft-versus-host disease.