Aplastic Anemia

There are two types of aplastic anemia: congenital and acquired. The acquired form represents over 90% of cases and usually results from an autoimmune attack against hematopoietic stem cells. The most common clinical manifestations reflect the low blood counts and include dyspnea on exertion, fatigue, easy bruising, petechia, epistaxis, gingival bleeding, heavy menses, headaches, and fever. The primary diagnostic procedure, in addition to a complete blood count, leukocyte differential, and reticulocyte count is the bone marrow aspirate and biopsy. The clinical response of aplastic anemia to immunosuppressive therapy provides the first data suggesting that aplastic anemia is immune mediated. More recently, it has been shown that the bone marrow in aplastic anemia is infiltrated with lymphocytes that secrete Th1 cytokines. Skewing of the Vβ repertoires demonstrated by CDR3 spectratyping further suggests that this is an antigen-driven autoimmune disorder. Moreover, newer methodologies are beginning to allow the study of the rare target cell populations in aplastic anemia.