[Allogeneic hematopoietic stem cell transplantation for patients with aplastic anemia]

Allogeneic hematopoietic stem cell transplantation (HSCT) from a human leukocyte antigen (HLA)-matched related donor is an effective treatment option for sever aplastic anemia (SAA). HSCT from an unrelated donor has also been reported. Engraftment failure and graft-versus-host disease (GVHD) are major obstacles in HSCT for SAA, and the combination of high-dose cyclophosphamide (CY) and anti-thymocyte globulin (ATG) has been utilized as a conditioning regimen for overcoming these obstacles. However, cardiac toxicity due to high-dose CY has been a major challenge, and the reduction of CY with the addition of fludarabine (Flu) has recently been considered to decrease toxicity. In Kanto Study Group for Cell Therapy (KSGCT), a prospective study using Flu, reduced-dose CY, and low-dose thymoglobulin as a conditioning regimen was performed, which demonstrated a promising result with the overall survival rate of 96.3% at one year. However, it should be noted that the use of Flu may affect the occurrence of secondary graft failure. Outcomes in HSCT from alternative donors, including cord blood and haploidentical-related donors, are improving. Therefore, we have more options in HSCT for SAA.