Graft-versus-leukemia in chronic lymphocytic leukemia.

Immune-mediated anti-leukemia effects, often termed graft-versus-leukemia (GvL), operate after bone marrow or blood cell transplants for acute lymphoblastic leukemia, acute myelogenous leukemia and chronic myelogenous leukemia. Sometimes the magnitude of this anti-leukemia effect exceeds that of high-dose anti-leukemia drugs and radiation and can result in leukemia cure. We analyzed leukemia relapse data after transplants for chronic lymphocytic leukemia (CLL) in this context. These data support the notion of a strong GvL effect in CLL. However, as most of these data are from studies of allotransplants, it is uncertain whether GvL operates in settings where the anti-leukemia effector cells and target CLL cells are genetically identical except for leukemia-related mutations. It is also uncertain whether GvL is distinct from GvHD. These potential limitations have important implications on whether immune therapy of CLL will work in non-allotransplant settings.