ABSTRACT
Allogeneic bone marrow transplantation (BMT) for relapsed or resistant leukemia was initially
conceived as a mechanism for rescuing the patient from the toxicities of intensive chemotherapy,
but studies from both the clinic and the laboratory soon demonstrated that the specific immune
responses of transplanted, allogeneic immune cells-predominantly T cells-made a significant
contribution to survival after BMT. Early observations of a correlation between development of
graft versus host disease (GVHD) and relapse-free survival led to the identification of a graft-
versus-leukemia (GVL) effect (1-4) that was potentially separable from the GVH response (5,6).
Yet precisely because BMT is used to treat those malignancies with the poorest outcomes,
relapses are frequent. Because allo-immune responses contribute the efficacy of therapy, the loss
of the GVL effect is an important part of relapse after BMT.
