Successful Reinduction of Remission by DLI for Relapsing Infant AML after Reduced-Intensity Hematopoietic Stem Cell Transplantation

Abstract

Infant cases with acute myeloid leukemia (AML) can be cured by combination chemotherapy. However, hematopoietic stem cell transplantation (SCT) is required in some refractory cases. We report a case of an infant with AML in which remission was successfully induced by donor lymphocyte infusion (DLI) against relapse after reducedintensity hematopoietic stem cell transplantation (RIST). In this case, we adopted RIST for the refractory disease in order to reduce treatment-related toxicities and late adverse effects, since he was an infant with AML in which alloreactive graft-versus-leukemia (GVL) effects were expected. Shortly after a transient remission following RIST, this case developed a recurrence. To induce GVL, we administered two courses of DLI, which resulted in complete reinduction of remission, suggesting that allo-reactive immune mechanism is effective for AML. Elevenmonths after DLI, the disease remained in remission, although the patient had fallen into bronchiolitis obliterans. This case implies a new therapeutic strategy for refractory infant AML, but further study is needed on this therapy.