Hematopoietic Stem Cell Transplantation and Immune System Suppression in Severe Aplastic Anemia

Aplastic anemia (AA) is characterized by pancytopenia and hypocellular bone marrow and can be either acquired or constitutional. Acquired AA results from autoimmune-mediated destruction of hematopoietic stem cells, often triggered by toxic agents inducing neo or cryptic antigens that activate immune responses. Although rare, acquired AA remains a serious condition typically managed with immunosuppressive therapy and supportive care. Constitutional forms, such as Fanconi anemia (FA) and Dyskeratosis Congenita (DC), are also uncommon and associated with genetic defects in DNA repair or telomere maintenance. Accurate differentiation between acquired and constitutional AA is critical for effective management. In our center, 15 patients were diagnosed with AA between 2016 and 2021 (acquired = 5, constitutional = 10). Patients with acquired AA received immunosuppressive therapy. Those with constitutional AA and HLA-matched donors underwent bone marrow transplantation following a conditioning regimen of busulfan, cyclophosphamide, and rabbit ATG. Cyclosporine was initiated two days prior to transplantation and continued for 6–12 months or longer. Despite the high mortality risk associated with untreated AA, all patients achieved favorable outcomes with no mortality, underscoring the critical role of early diagnosis and individualized treatment in improving survival in AA.