Bone marrow transplantation in leukemia. Current status.

Intensive cytoreductive therapy may be curative in certain hematopoietic malignancies, but its administration is limited by lethal marrow toxicity. Bone marrow transplantation (BMT) provides a way of rescue from this toxicity. The donor may be a human leukocyte antigen (HLA) "matched" sibling (allogeneic), an identical twin (syngeneic), or the patient (autologous). Long remissions and possible cures of 50% to 60% have been reported in acute leukemia after intensive treatment with chemotherapy, with and without total body irradiation, followed by allogeneic BMT. A similar approach has been used in chronic myelocytic leukemia (CML) and in non-Hodgkin's lymphoma with encouraging results. Results are best in younger patients and those transplanted early in their disease (i.e., in the first remission for acute leukemia and in the chronic phase of the disease in CML). Solutions to major problems associated with allogeneic BMT, such as graft-versus-host disease and viral infections, are being actively pursued. Syngeneic BMT avoids some of the above problems, but relapses appear to be greater. Nevertheless, this approach has produced a significant number of cures. Autologous BMT is the newest approach, and the demonstration that marrow may be purged of residual tumor cells by immunologic or pharmacologic means has engendered enthusiasm for this area of clinical therapeutic investigation.