Donor lymphocyte infusions for relapse of chronic myeloid leukemia after allogeneic stem cell transplantation: Prognostic significance of the dose of CD3⁺ and CD4⁺ lymphocytes

Between December 1993 and November 2001, 30 patients with chronic myeloid leukemia who relapsed after stem cell transplantation were studied. Seventeen patients were not treated before donor lymphocyte infusion (DLI), eight patients received interferon-α (IFN-α), and five underwent chemotherapy. The method of DLI was the bulk dose regimen. The median time between DLIs was 6 weeks. The median number of infusions was three; the median time from transplant to relapse was 17 months and from relapse to DLI 2 months. Eleven patients (37%) were in molecular/cytogenetic relapse, 14 (47%) in chronic phase, and five (16%) in accelerated or blastic phase. Seventeen patients (57%) developed acute graft-versus-host disease (GVHD). Chronic GVHD was observed in 15 of 24 (62%) patients. Four (13%) patients developed cytopenia after a median of 30 days. Nineteen (63%) patients achieved response, 15 of them developed GVHD. The response rate according to the disease phase was molecular or cytogenetic relapse: 91%, chronic phase: 57%, and accelerated or blastic phase: 20%. The median time to response was 6 months. Patients treated with IFN-α or no treatment as well as those who were in molecular/cytogenetic relapse and those who received a CD3⁺ cell dose <1×10⁸/kg and CD4⁺ <8×10⁷/kg had better survival. We conclude that patients who receive lower doses of lymphocytes have better survival. In some patients IFN-α seems to be a good choice to potentiate the graft-versus-leukemia (GVL) effect.