Allogeneic hematopoietic stem cell transplantation for acquired severe aplastic anemia: a summary of a 20-year experience.

Abstract

Severe aplastic anemia (SAA) is a rare but potentially fatal disorder characterized by hypocellular bone marrow and resulting in pancytopenia. It can be cured with allogeneic hematopoietic stem cell transplantation (allo‑HSCT), especially in young individuals. The main objective of the study was to assess the safety of the procedure and to identify the factors influencing long‑term post‑transplant outcome. Using our institutional database, we performed a retrospective analysis of the patients with SAA allotransplanted in the years 2001-2021. Seventy patients (49 men) at a median age of 25 years at transplantation underwent allo‑HSCT. Thirty-eight patients received immunosuppressive treatment (IST) before transplantation. Twenty-one patients received grafts from human leukocyte antigen-matched sibling, 44 from unrelated donors, and 5 from haploidentical related donors. Peripheral blood remained the source of stem cells in the majority of patients. Primary graft failure was observed in 2 cases. The incidence of acute graft‑versus‑host disease (GVHD) was 44%, whereas chronic GVHD was observed only in 4 patients. Median follow‑up was 3 years (interquartile range, 0.45-11.5). Post‑transplant outcome was comparable between patients with upfront allo‑HSCT and those who relapsed after IST. In the univariable analysis, only a higher Eastern Cooperative Oncology Group (ECOG) score at transplantation and infections in the post‑transplant period were found to be associated with unfavorable outcome. Fifty‑three patients were alive at last contact. Most transplanted patients died due to infectious complications. A 2‑year overall survival was 73%. The results of allo‑HSCT in SAA are satisfactory and offer long‑term survival and good quality of life. Higher ECOG score and the presence of infections are associated with poor post‑transplant outcome.