At the 42nd Annual Meeting of the European Society for Blood and Marrow Transplantation, held in Valencia, Spain, Arnon Nagler, MD, from Sheba Medical Center, Tel Hashomer, Israel, talks about the separation of graft-versus-leukemia from graft-versus-host disease (GvHD). A good readout assay for graft-versus-leukemia is currently unavailable, besides lack of patient’s relapse or GvHD development. Patients with GvHD usually have less relapse; this gives an opportunity for patients with low-grade GvHD to benefit from the immunological attack against leukemia caused by allogeneic transplant without morbidity or mortality of GvHD.