The Pathophysiology And Treatment Of Aplastie Anemia

Aplastie Anemia (AA) is a heterogeneous disease characterized by failure of bone marrow hematopoiesis resulting in various degrees of pancytopenia with a hypocellular bone marrow. Clinically , patients with AA may present with anemia,bleeding and serious infection.Despeite the exact causes of AA are unknown,the disease may result from the combined effects of multiple noxious exposures on plurpotential stem eells. Potential mechanisms responsible for aequired AA include defects in hematopoietic stem cells,failure of the bone marrow microenvironment impairing the production or release of hematopoietie growth factors,and cellular or humoral immune suppression of the marrow. In different patiens these three mechanism underplay singly or unitedly. The introduction of immunosuppression therapies with antithymocyte globulin,and cyclosporine A in the treatment of AA has improved the prognosis. Almost 70% patiens recovered following immunosuppression therapy suggesting that immunosuppression may be the most important mechnism.Immunosuppressive therapy (IST) remains an important option for AA patients who are not candidates for transplantation. Favorable prognostic indicators for IST are young age and a short interval from diagnosis; The outcome of allogeneic bone marrow transplantations has significantly improved in the past decade, particularly in the unrelated donor setting. A short interval between diagnosis and treatment will also improve results for bone marrow transplantation; these rare patients should be referred to an experienced center immediately.