Intrathecal donor lymphocyte infusion for isolated leukemia relapse in the central nervous system following allogeneic stem cell transplantation: a case report and literature review.

An 8-year-old boy with a bone marrow relapse of T cell acute lymphoblastic leukemia underwent stem-cell transplantation from a human leukocyte antigen (HLA)-haploidentical mother. Five months later, he relapsed with central nervous system (CNS) involvement. Systemic chemotherapy and repeated intrathecal chemotherapy induced consciousness disturbances and frequent arrhythmia, prompting us to discontinue the chemotherapy. He had already received an 18-Gy prophylactic cranial irradiation, an 8-Gy total body irradiation, and a 15-Gy local irradiation for pituitary gland involvement. We therefore performed five intrathecal donor lymphocyte infusions (IDLIs) in escalating doses from 1 × 10(4) up to 1 × 10(6) cells/kg. All IDLIs were safe without infusion reactions or graft-versus-host disease. After the second and later IDLIs, donor mononuclear cells were continuously detected in cerebrospinal fluid; however, he did not achieve donor-dominant chimerism. Based on our case and four cases reported in the literature, the efficacy of IDLI therapy is limited for CNS relapse of hematological malignancies. However, we suggest that IDLI remains a feasible and safe option, as no GVHD or other adverse effects occurred, even in the HLA-haploidentical setting. We will make further efforts to increase the efficacy.