BACKGROUND: Donor leukocyte infusion (DLI) is an effective therapy for patients who relapse with leukemia after allogeneic bone marrow transplantation (BMT). This is due to the fact that the immune reactivity of infused allogeneic lymphocytes on relapsed leukemia cells plays a major role in the control of leukemia. However, severe graft-versus-host disease (GVHD) and pancytopenia compromise the success of this treatment in a substantial number of patients. METHODS: To evaluate the effect of DLI, we surveyed 6 BMT centers regarding their use of DLI for relapsed leukemia after BMT. Detailed forms were used to gather data regarding the original BMT, relapse, response to DLI, complication and survival. Reports of 11 patients were consequently available for analysis. RESULTS: Five (83.3%) of 6 patients with chronic myeloid leukemia (CML) achieved complete remission (CR) [time-to-CR; 116 (27~180) days after DLI], and currently 4 are alive in CR (49~436 days). Five patients (83.3%) developed GVHD, and 2 developed pancytopenia which was related to DLI. In acute leukemia, all patients received salvage chemotherapy prior to DLI. Only 1 of 3 patients with acute lymphoblastic leukemia (ALL) who had early relapse achieved CR, but durable remission was not yet confirmed (62+ days). Both 2 patients with acute myeloid leukemia (AML) achieved CR, and their CR durations were 242+ and 326 days after DLI, respectively. CONCLUSION: This study demonstrates that DLI can exert considerable effects against myeloid forms of leukemia, especially in CML. Further investigations of separating GVHD from the graft- versus-leukemia effect and finding more effective anti-leukemia approaches on acute leukemiaare necessary to improve the current DLI limitations.