ANTI-LEUKEMIC EFFECT OF GRAFT VERSUS HOST DISEASE IN HUMAN RECIPIENTS OF ALLOGENEIC MARROW GRAFTS

To determine whether allogeneic bone-marrow transplantation is associated with a graft-versus-leukemia effect, we examined the relation between relapse of leukemia and graft-versus-host disease in 46 recipients of identical-twin (syngeneic) marrow, 117 recipients of HLA-identical-sibling (allogeneic) marrow with no or minimal graft-versus-host disease, and 79 recipients of allogeneic marrow with moderate to severe or chronic disease. The relative relapse rate was 2.5 times less in allogeneic-marrow recipients with graft-versus-host diseas tha in recipients without it (P<0.01). This apparent antileukemic effect was more marked in patients with lymphoblastic than nonlymphoblastic leukemia, and in those who received transplants during relapse rather than during remission, and was most evident during the first 130 days after transplantation. Survival of all patients was comparable since the lesser probability of recurrent leukemia in patients with graft-versus-host disease was offset by a greater probability of other causes of death. (N Engl J Med 300:1068–1073, 1979) ONE of the theoretical indications for attempting allogeneic bone-marrow transplantation in patients with acute leukemia is the possibility that the marrow graft will exert an antileukemic effect.1,2 Evidence of this effect in rodent tumor systems has been reviewed.3,4 Evidence of the existence of a graft-versus-leukemia effect in human recipients of allogeneic bone-marrow grafts has been difficult to obtain because of the large number of deaths from other causes among patients with severe graft-versus-host disease (GVHD).5,6 Some patients without GVHD have remained free of leukemia for two to eight years after transplantation, whereas recurrent leukemia has developed in other patients with. © 1979, Massachusetts Medical Society. All rights reserved.