Introduction
Severe aplastic anemia (SAA) is a serious hematological disease characterized by bone marrow (BM) hypoplasia and pancytopenia in the peripheral blood. Immunosuppressive therapy (IST) and hematopoietic stem cell transplantation (HSCT) have been considered two effective treatment choices in SAA. Despite the great advances in immunosuppressive therapy for severe aplastic anemia (SAA), most patients are not completely cured. Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) has been recommended as an alternative treatment in adult SAA patients. However, haplo-HSCT presents a higher incidence of graft failure and graft-versus-host disease (GVHD). In the current study, the authors report promising clinical outcomes in a cohort of 25 adult SAA patients (≥18 years) who received umbilical cord-derived MSCs (UC-MSCs) and haplo-HSCs. Additionally, the therapeutic effects and transplantation-associated complications in adult SSA patients were compared with those observed in juvenile SAA patients (<18 years, N = 75).
Methods
Adult patients (≥18 years) with SAA (N = 25) were given HLA-haploidentical hematopoietic stem cells (HSCs) combined with UC-MSCs after a conditioning regimen consisting of busulfan, cyclophosphamide, fludarabine and anti-thymocyte globulin and intensive GVHD prophylaxis, including cyclosporine, basiliximab, mycophenolate mofetil and short-term methotrexate. Additionally, the effects of the protocol in adult SSA patients were compared with those observed in juvenile SAA patients (N = 75).
Results
All patients achieved myeloid engraftment after haplo-HSCT at a median of 16.12 days (range, 11–26). The median time of platelet engraftment was 28.30 days (range, 13–143). The cumulative incidence of grade II acute GVHD (aGVHD) at day +100 was 32.00 ± 0.91%. No one had grade III–IV aGVHD at day +100. The cumulative incidence of total chronic GVHD was 28.00 ± 0.85%. The overall survival was 71.78 ± 9.05% at a median follow-up of 42.08 months (range, 2.67–104). Promisingly, the protocol yielded a similar curative effect in both young and adult SAA patients.
Conclusions
In the present study, the authors report the results of a protocol of co-transplantation of haplo-HSCs and UC-MSCs for adult SAA patients. The authors’ study demonstrates that the protocol is safe and curative. However, the effects of the protocol on more adult SAA patients, including a comprehensive analysis of the underlying mechanisms of the protocol, need to be further investigated in future studies.
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