Activated allogeneic cell therapy (allo-ACT) for relapsed chronic myelogenous leukemia (CML) refractory to buffy coat transfusions post-allogeneic bone marrow transplantation

We describe a 17-year-old male patient with chronic myelogenous leukemia (CML) in hematologic and cytogenetic relapse 4 months post-non-T cell-depleted allogeneic bone marrow transplantation for accelerated CML. Two sequential buffy coat transfusions with donor peripheral blood cells (8.9 and 4.8 x 10⁷ cells/kg), the second transfusion in combination with in vivo activation of donor cells by human recombinant interleukin-2 (rIL-2) 6 x 10⁶ IU/m² subcutaneously for 3 days, failed to induce remission. The patient responded to an infusion of donor peripheral blood lymphocytes (3.3 x 10⁷ cells/kg) pre-activated in vitro with rIL-2 and additionally activated in vivo with rIL-2, 6 x 10⁶ IU/m²/day subcutaneously for 3 days. Elimination of the Philadelphia (Ph) clone was confirmed by cytogenetic analysis showing a normal male karyotype and by disappearance of the bcr/abl transcript, using the polymerase chain reaction (PCR). At present, the patient is 26 months post-treatment with no evidence of disease, but with chronic graft-versus-host disease. Our data indicate that allogeneic activated cell therapy (allo-ACT) may provide antitumor effector cells that successfully induce graft-versus-leukemia (GVL) effects even when cell therapy with donor buffy coats was insufficient.