Should we T cell deplete sibling grafts for acute myeloid leukaemia in first remission?

There is controversy regarding the best approach to the management of patients with acute myeloid leukaemia (AML) in first remission (CR1). The impact of matched related allogeneic transplant in CR1 on the overall survival is equivocal, but what is not in doubt is a significant reduction in the relapse risk, compared to both autologous transplants and intensive chemotherapy, which is because of the allogeneic or the graft-versus-leukaemia (GVL) effect. Yet, this does not always translate to improved survival. T cell depletion (TCD) can reduce deaths related to graft-versus-host disease (GVHD) and its therapy, but might increase the relapse risk. The existing literature suggests that TCD is associated with a disease-free survival (DFS) of 53-80% and is associated with a lower relapse risk than anticipated (0-30%). We discuss the evolution of TCD in allogeneic transplantation and its relevance in AML-CR1 with regard to GVHD, DFS, immune reconstitution and GVL effect. It is possible that by reducing TRM related to GVHD and extramedullary toxicities, particularly in the older patients, TCD might improve the impact of allogeneic transplantation in AML-CR1, provided the immune reconstitution and the relapse risk are not adversely affected. Randomised studies are underway to address these issues.