The role of disease stage in the response to donor lymphocyte infusions as treatment for leukemic relapse.

Between 1991 and 1999, 44 leukemic patients received donor lymphocyte infusions (DLIs) at our center (22 patients with chronic myelogenous leukemia [CML]; 10 with acute myelogenous leukemia; 11 with acute lymphatic leukemia; and 1 with myelodysplastic syndrome). Seventeen patients received graft-versus-host disease (GVHD) prophylaxis with methotrexate (MTX) at the time of DLI. In CML patients, 15 of 22 (68%) re-entered complete remission after DLI. At 3 years post-DLI, patients with cytogenetic (n = 10) or molecular (n = 3) relapse had a current leukemia-free survival (cLFS) rate of 85% compared with 0% for patients with hematologic relapse (P < .001). Among 15 CML patients who initially responded to DLI, 4 patients relapsed within the first 2 years. Four of 16 patients (25%) with acute leukemia had an initial response with complete remission after DLI. Two of them subsequently relapsed within 1 year. Patients with acute leukemia who relapsed within 1 year of hematopoietic stem cell transplantation (n = 9) had 0% cLFS at 18 months; patients with later relapse had 29% cLFS (P = .015). The overall probability of cLFS at 3 years for CML patients was 46%. For other diseases, cLFS was 13% at 18 months after DLI. Patients who developed chronic GVHD secondary to DLI showed a 3-year cLFS of 51% compared with 18% for patients without chronic GVHD (P = .022). This study emphasizes the importance of early disease stage and presence of chronic GVHD for effective DLI.