Efficacy of Unrelated Allogeneic Hematopoietic Stem Cell Transplantation in Severe Aplastic Anemia: A Single-Center Retrospective Study.

To evaluate the efficacy of unrelated allogeneic hematopoietic stem cell transplantation (URD-HSCT) in severe aplastic anemia (SAA), this study retrospectively analyzed the clinical data of 206 patients at a single center. The median age was 28 years (range: 5-64 years), and 13.6% had received immunosuppressive therapy prior to transplantation. The median time to neutrophil and platelet engraftment was 12 days (range: 9-22 days / 8-55 days), respectively, with a graft failure rate of 3.4%. The cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) was 21.7% (95% CI: 16.6%-27.8%), and that of chronic GVHD was 20.4% (95% CI: 15.4%-26.6%). Survival analysis revealed a 7-year overall survival (OS) rate of 91% for the entire cohort. Notably, the 7-year OS rate was significantly higher in the donor age ≤30 years group compared to the >30 years group (97% vs 85%, P = 0.0028), and in the HLA 10/10 matched group compared to the 9/10 matched group (95% vs 86%, P = 0.023). Multivariate analysis identified donor age >30 years, and HLA 9/10 matching as independent risk factors for OS and graft-versus-host disease-free, relapse-free survival (GRFS). URD-HSCT is an effective treatment for SAA, and selecting an appropriate donor can improve treatment outcomes.