Allogeneic stem cell transplantation is the only effective treatment to patients resistant to conventional chemotherapy. Donor lymphocytes infusion (DLI) serve as a routine treatment of choice for patients relapsing following allogeneic stem cell transplantation. The present proposal is presented for introducing the use of immune rather than naive donor lymphocytes for patients with resistant relapse and resistant to DLI. DLI primed in-vitro against tumor cells of host origin or against host alloantigens presented by parental alloantigens in one way mixed lymphocytes culture can induce much more than potent graft-vs-leukemia and graft-vs-tumor effects, while down-regulating graft-vs-host disease (GVHD).