Allogeneic Hematopoietic Stem Cell Transplant for Severe Aplastic Anemia: Current State and Future Directions.

Acquired severe aplastic anemia (SAA) is a rare and life-threatening bone marrow failure syndrome characterized by cytotoxic T-cells excessive activity, hematopoietic precursors decrease and peripheral blood (PB) pancytopenia. Patients with severe aplastic anemia (SAA) die 1 to 2 years after diagnosis due to fatal infections and/or hemorrhagic complications if they do not undergo any effective treatment. Nowadays, Immunosuppressive therapy (IST) and allogeneic hematopoietic stem cell transplantation (HSCT) are still the standard treatment for SAA. For patients younger than 40 years old, allogeneic HSCT is often the best choice. Recently, outcomes of matched unrelated donor and haploidentical donor transplantation have significantly improved, notably in some cases which are comparable to the result of matched related donor transplantation. Mixed chimerism status is more common in SAA post-transplantation patients, which is effected by conditioning regimen used in transplantation and is closely relevant to donor cells rejection and secondary graft failure. In this article, we briefly have reviewed the current state and future directions for SAA HSCT, and have shared our SAA data and transplant experience of the recent decade. We have analyzed the impact of conditioning regimen on engraftment and chimerism status in SAA transplantation, and have compiled our findings in this report.