[Clinical study of allogeneic hematopoietic stem cell transplantation for relapsed/refractory acute lymphocytic leukemia].

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

METHODS: Forty-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).

RESULTS: All 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.

CONCLUSION: Allo-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.