Prophylactic Donor Lymphocyte Infusions in Pediatric Patients With High-Risk Hematological Malignancies.

[INTRODUCTION] Allogeneic stem cell transplantation (allo-SCT) and donor lymphocyte infusions (DLI) can elicit a graft-versus-leukemia (GvL) effect in pediatric patients with hematological malignancies. We report our single-center experience with prophylactic DLI in high-risk pediatric patients with leukemia or lymphoma, focusing on feasibility, safety, and efficacy.

[METHODS] In total, 10 high-risk patients received prophylactic DLI following allo-SCT. Donors were either matched (n = 5) or haploidentical (n = 5). CD3+ T-cell doses of up to 1 × 10 cells/kg body weight were administered, in some cases over extended periods exceeding three years.

[RESULTS] The treatment was associated with a favorable toxicity profile. In our cohort, 40% of patients developed moderate acute (n = 2) or chronic (n = 2) graft-versus-host disease (GvHD); no cases of severe or high grade GvHD occurred. Given the high-risk profile of our cohort, outcomes were encouraging, with relapse-free survival (RFS) of 70% and overall survival (OS) of 80% at a median follow-up of 20.5 months. Especially, the two subgroups of patients with acute myeloid leukemia (AML) after relapse and patients who were transplanted in first complete remission (CR1) showed outcomes superior to currently reported data. One AML patient, who had experienced three relapses, received prophylactic DLI after a third allo-SCT and remains in complete remission (CR), more than 3 years after the last allo-SCT.

[CONCLUSION] These data suggest that prophylactic DLI may represent a safe and effective treatment option for pediatric patients with hematological malignancies at high risk of posttransplant relapse.