ABSTRACT
Objective:To explore the efficacy and safety of unrelated mismatched hematopoietic stem cell transplantation(HSCT)for thalassemia major.Methods:For this retrospective cohort study, 15 patients with β-thalassemia major underwent unrelated mismatched HSCT between January 2018 and April 2022. There were 8 males and 7 females with a median age of 7(3-12)years and a median ferritin level of 3 417.3(223-14 485)μg/L. The conditioning regimens on the basis of fludarabine(Flu), busulfan(Bu)and cyclophosphamide(CTX)and GVHD prophylaxis on the basis of cyclosporine(CsA), mycophenolate mofetil(MMF), anti-human thymocyte immunoglobulin(ATG)plus low-dose post-cyclophosphamide(PTCy)and mesenchymal stem cells were offered.Results:Up until April 1, 2022, 15 children were successfully implanted during a median follow-up period of 24.1(11-49)months and all of them achieved stable donor chimerism. The median time to neutrophil and platelet engraftment were 12(11-22)and 14(8-38)days respectively. Except for 2 deaths, 13 cases survived. The estimated 2-year probability of overall survival(OS)and thalassemia-free survival(TFS)were both 86.67%. There were 5 cases of acute graft versus host disease (aGVHD) below grade Ⅱ, 2 cases of grade Ⅲ to Ⅳ aGVHD, and 3 cases of localized chronic graft versus host disease (cGVHD) after transplantation. No gengralized cGVHD occurred. Both cytomegalovirus and Epstein-Barr virus were activated in five recipients.Conclusions:Unrelated mismatched donor HSCT is both safe and feasible for thalassemia major.