Impact of CD34 Cell Dose and Conditioning Regimen on Outcomes after Haploidentical Donor Hematopoietic Stem Cell Transplantation with Post-Transplantation Cyclophosphamide for Relapsed/Refractory Severe Aplastic Anemia.

•Hematopoietic stem cell transplantation from haploidentical donors for relapsed/refractory severe aplastic anemia is feasible.•Primary graft failure was 15%, 2-year event-free survival (EFS) was 70%, and 2-year overall survival was 79%.•An augmented cyclophosphamide/fludarabine/total body irradiation regimen is associated with improved EFS.•A CD34 cell dose >3.2 × 10E6/kg is associated with improved EFS.