Abstract
Results of T-cell receptor β-chain repertoire analysis, gene expression profiling studies of CD34-positive cells from patients with aplastic anemia, and other cytokine data have shown that the major pathogenic mechanism of acquired aplastic anemia is stem cell injury by morbid T-cells. Several proteins, such as kinectin and diazepam-binding inhibitor-related protein 1, have been found to be related to the onset as self-antigens. With these findings and additional new clues the pathogenesis of aplastic anemia will soon be clarified. The current strategies to treat severe aplastic anemia are stem cell transplantation and immunosuppressive therapy with anti-thymocyte globulin and cyclosporine. These methods have both benefits and some problems, so it is sometimes not easy to determine which therapy should be applied to patients. Some data suggest that the presence of paroxysmal nocturnal hemoglobinuria (PNH) clones in patient's peripheral blood heralds a good response to immunosuppressive agents. PHN clones may be a useful tool for selecting therapy. For stem cell transplantation, an HLA-identical sibling is the best donor candidate, but such a donor is available for only 30% of patients. Recently, HLA-mismatched related or HLA-matched unrelated bone marrow cells and HLA-mismatched umbilical cord blood cells have been used as alternative stem cell sources if an HLA-identical sibling donor is not available. However, greater efforts must be made to reduce the mortality and morbidity rates of stem cell transplantation. In this paper recent progress in the basic research and treatment of aplastic anemia are reviewed.
