Long-Term Results of Donor Lymphocyte Transfusions for the Treatment of Relapse After Allogeneic Transplantation for Chronic Myelogenous Leukemia - Is There a Role for Immunotherapy in CML?.

Abstract 2258

Poster Board II-235

The long-term outcome of donor lymphocyte infusions (DLI) as first line treatment of relapse of chronic myeloid leukemia (CML) after allogeneic stem cell transplantation was studied and compared to other treatment modalities. Forty five patients were treated with DLI and 36 without DLI. Patients given DLI first did not differ significantly from those given other treatments in gender, age, donor, gender and histocompatibility of the donor, source of stem cells (blood vs marrow), depletion of T cells, stage of the disease, time from diagnosis and year at the time of transplant, acute and chronic graft-versus-host disease (GVHD) and remission duration. The survival of the DLI group was 66.4 percent at 10 and 15 years after transplantation, it was 42.2 and 23.8 percent respectively in the non-DLI group (p=0.019, log rank). Excluding patients with early relapse in the first 6 months the survival of the DLI group was 78 percent at 15 and 20 years, 70 and 26 percent respectively of the non-DLI group (p=0.009). Recurrent leukemia was the predominant cause of death in both groups (11 of 14 patients of the DLI-, 21 of 23 patients of the non-DLI group). Three patients in the DLI group died of recurrent infections, bronchiolitis obliterans (BO) and heart failure respectively, and 2 patients of BO in the non-DLI group. The proportion of surviving patients with positive PCR for bcr/abl was not different in both groups (2 of 13 patients of the non-DLI and 7 of 30 patients in the DLI group). The better survival of the DLI group indicates a better control of residual leukemia by a persistent immune effect. The response to DLI was improved by simultaneous treatment with low doses of interferon-a and GM-CSF. The combination of these cytokines without DLI and transplantation remains to be defined in patients that do not tolerate or respond incompletely to Imatinib. The role of immunotherapy for induction and maintenance of remission is well established in transplant patients.