Donor leukocyte transfusions for treatment of leukemic relapse after bone marrow transplantation

Allogeneic bone marrow transplantation is an effective treatment of leukemia. Intensive chemo- and radiotherapy used for conditioning and T-cells of the graft contribute to the control of leukemia. Animal experiments indicate that transfusion of lymphocytes from the marrow donor convert into complete chimerism without producing graft-versus-host disease, if delayed for two months or more. Transfusion of donor leukocytes (DLT) after marrow transplantation has induced lasting remissions in the majority of patients with chronic myelogenous leukemia (CML) in hematological or cytogenetic relapse, some patients with acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), transformed phase CML and multiple myeloma (MMY). The mechanism of the graft-versus-leukemia reaction is discussed.