Immunotherapy of relapsed resistant chronic myelogenous leukemia post allogeneic bone marrow transplantation with alloantigen pulsed donor lymphocytes

Allogeneic cell-mediated immunotherapy with donor lymphocyte infusion (DLI) can successfully reverse chemoradiotherapy-resistant relapse in patients with chronic myeloid leukemia treated by allogeneic bone marrow transplantation (BMT). We describe the first successful attempt in 1992 to treat DLI-resistant relapse in a patient with CML in full hematologic relapse, using immunized donor lymphocytes. Donor lymphocytes were pulsed in vitro with a mixture of irradiated peripheral blood lymphocytes (PBL) obtained from both parents, in order to trigger alloactivation of donor lymphocytes against host alloantigens presented by parental cells, using as stimulating cells maternal PBL expressing the shared maternal haplotype and paternal PBL expressing the shared paternal haplotype of the patient. Full hematologic, cytogenetic and molecular remission was induced for the first time, independently of GVH, and has persisted for more than 9 years. To the best of our knowledge, this report represents the first successful immunotherapy with donor lymphocytes activated against host-type antigens. We suggest that immune donor PBL may be superior to DLI, possibly effective even when all other modalities fail, perhaps even independently of GVHD.