Graft versus Leukemia Reactivity after Allogeneic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (alloSCT) can produce durable remissions in many patients suffering from hematologic malignancies. The elimination of malignant cells after the transplant was initially thought to be attributable to the myeloablative chemotherapy and irradiation administered during the procedure, and infusion of hematopoietic stem cells was necessary to restore normal hematopoiesis. Autologous hematopoietic cell grafts or grafts derived from an identical twin were felt to provide the optimal source of hematopoietic stem cells for transplantation, because the use of grafts from allogeneic donors was associated with immunologic complications including severe graft-versus-host disease (GVHD).