BACKGROUND:The main therapy of severe aplastic anemia in children is immunosuppressive therapy or stem celltransplantation, but the latter one is restricted due to few donor sources. Haploidentical hematopoietic stem celltransplantation is commonly used in leukemia, but it is stil rarely reported in the treatment of aplastic anemia. OBJECTIVE:To investigate the effect of haploidentical hematopoietic stem celltransplantation combined with placenta-derived mesenchymal stem celltransplantation for children with severe aplastic anemia. METHODS:A 7-year-old girl who had been confirmed as having severe aplastic anemia for 1.5 years received a cotransplantation of haploidentical hematopoietic stem cells combined with placenta-derived mesenchymal stem cells on July 9th , 2012. The donor was her mother. The preconditioning regimen consisted of fludarabine, cyclophosphamide, and anti-thymocyte globulin. RESULTS AND CONCLUSION:Time of neutrophil recovery (>0.5×10 9/L) was+9 days, and hematopoietic reconstruction was complete at+12 days. The short tandem repeat analysis showed 100%donor’s genotype at+100 days. Immunosuppressive drugs were stopped at+8 months, and no acute or chronic graft-versus-host disease occurred. With a fol ow-up of 18 months, she was in the disease-free survival period. Our findings suggest that the cotransplantation of al ogeneic haploidentical hematopoietic stem cells and placenta-derived mesenchymal stem cells is a new effective approach for children with severe aplastic anemia, which is worth exploring in the future.

Objective To observe the efficacy and safety of reduced-intensity conditioning regimen used in allogeneic hematopoietic stem cell transplantation (HSCT) for children with β-thalassemia major.Methods We retrospectively analyzed the clinical data of 15 children with β-thalassemia major undergoing allogeneic HSCT with a reduced-intensity conditioning regimen from March 2013 to March 2017.Fifteen patients were diagnosed definitely,and the median age at transplantation was 5 years (range:3-6 years),including 11 with HSCT from unrelated donors (UDs),3 of HLA 8/10 matched and 8 of HLA10/10 matched.The remaining 4 patients out of 15 with HSCT were from related donors with HLA matched,3 donors were siblings and 1 was mother.All patients used a reduced-intensity conditioning regimen.The median mononuclear cell (MNC) dose and CD34 positive cell dose were 11.4 × 108/kg (range:4.8-20 × 108/kg)and 9.8 × 106/kg (range:5.9-27.2 × 106/kg),respectively.Graft-versus-host disease (GVHD) was prevented by cyclosporine A,methotrexate,MMF and ATGf.Results All 15 patients had successful engraftment.Median time to neutrophil and platelet engraftment was 12 days (range:9-21 days) and 15 days (range:10-25 days) respectively.Two patients developed grades Ⅱ acute GVHD and 4 patients developed chronic GVHD from unrelated donors,while there was no acute GVHD and 1 patient developed chronic GVHD from related donors.No patients suffered from serious transplantation-related complications,such as hepatic veno-occlusive disease (VOD),hemorrhagic cystitis,EB virus reactivation,CMV reactivation and hepatitis C,etc.The median follow-up time was 24 months (range:2-48 months).All patients were healthy and became transfusion-independent.Conclusion The reduced-intensity conditioning regimen proved to be safe and effective for children with β-thalassemia major given allogeneic HSCT.

Objective:To explore the safety and advantages of non-cryopreserved sibling umbilical cord blood hematopoietic stem cell transplantation for major thalassaemia in children.Methods:From October 2016 to June 2021, 9 patients with major beta thalassaemia received non-cryopreserved hematopoietic stem cell transplantation of sibling umbilical cord blood at Zhongshan Hospital of Xiamen University. The pretreatment scheme, the process of stem cell implantation and follow-up were analyzed and summarized.Results:Among the 9 cases, there were 5 males and 4 females with a median age of 4(2~11)years. Median level of ferritin was 2 997(1 936~5 512)μg/L. At gestational weeks 12~16, each patient's mother underwent villi testing to confirm that the donor without thalassaemia major was complete HLA-matched with the patient. All of them received an intensive conditioning regimen made up of cyclophosphamide(CTX), fludarabine and busulfan(Bu). Graft-versus-host disease(GVHD) was prevented by cyclosporine A(CSA)and mycophenolate mofetil(MMF)with or without methotrexate(MTX). Except for one failed implant, 8 cases were successfully engrafted. Median time of neutrophil implantation was 19.5(15~26)days, median time of platelet implantation 32(22~34)days and median time of erythrocyte implantation 30.5(18~37)days. Up until September 1, 2021, the median follow-up period was 27(3~59)months and the rate of successful engraftment 88.89%. There was no transplant-related mortality. Overall survival was 100% and thalassaemia-free survival 88.89%. Two patients developed grades Ⅱ skin acute GVHD(22.2%). No grade Ⅲ-Ⅳ GVHD or chronic GVHD occurred. Epstein-Barr virus infection occurred in 1 case.No infection of cytomegalovirus occurred.Conclusions:For major thalassaemia in children, stem cell transplantation of non-cryopreserved sibling cord blood is both safe and feasible with a high implantation rate and a low incidence of GVHD.