OBJECTIVETo explore the efficacy and toxicity of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for relapsed/refractory acute lymphocytic leukemia (ALL).

METHODSForty-seven patients with relapsed/refractory ALL received allo-HSCT, which containing 19/47 from HLA-identical sibling donors (sib-HSCT), 18/47 from HLA-identical unrelated donors (URD-HSCT) and 10/47 from haplo-identical donors (Hi-HSCT). Conditioning regimens included "TBI plus Cyclophosphamide (Cy) (42/ 47)" or "busulfan (Bu) plus Cy (5/47)". Cyclosporine (CsA) combined with a short-course Methotrexate (MTX) were used for graft versus host disease (GVHD) prophylaxis. In addition, patients receiving URD-HSCT or Hi-HSCT were given mycophenolate mofetil (MMF) and anti-thymocyte immunoglobulin (ATG). Patients with molecular or cytogenetic relapse tendency on minimal residual disease (MRD) monitoring received donor lymphocyte infusion (DLI).

RESULTSAll patients tolerated the therapy well except for mucositis. Renal dysfunction occurred in 2 patients on CsA therapy. Epilepsy occurred in 1 patient, fatal infectious complications in 9 (including 3 interstitial pneumonia), grade III-IV acute GVHD (aGVHD) in 7, chronic GVHD (cGVHD) in 22 and hemorrhagic cystitis (HC) in 4 patients. Thirteen patients relapsed after transplantation. The median time of hematopoietic reconstitution was + 17 ds. Nineteen patients received DLI, and 6 of them had no disease progression. With a median follow-up duration of 43 (10-77) months, the estimated 5-year overall survival (OS) and disease free survival (DFS) rates were 49.65% and 46.55%, respectively.

CONCLUSIONAllo-HSCT is an effective therapy for relapsed/refractory ALL. Relapse after transplantation, fatal infection, and severe acute GVHD are the main causes for failure. DLI might decrease the relapse rate after transplantation.