[Studies of bone marrow T lymphocytes in patients with aplastic anemia].

OBJECTIVE: To study the role of immunological factors in the pathogenesis of aplastic anemia(AA). METHODS: Phenotype of T lymphocytes in bone marrow and CFU-GM yields of bone marrow mononuclear cells with or without T cells were assayed with APAAP and semi-solid culture method, respectively. RESULTS: The percentage of lymphocytes in bone marrow of AA patients was higher than that of normal controls, and the lymphocytes were mainly CD8 and CD25 positive cells. Changes of T lymphocyte subsets in peripheral blood of AA patients did not completely reflect the changes in the bone marrow. In some AA patients, increased percentage of CD8+ cells was found in bone marrow, while it was normal in peripheral blood. The CFU-GM yields of bone marrow cells of AA patients were much lower than that of normal controls, and were markedly improved by removing T cells before culture. CONCLUSION: The abnormalities of cell-mediated immune response played important roles in the pathogenesis of AA. The changes of T lymphocytes in bone marrow were more meaningful than that in peripheral blood. It is suggested that bone marrow T lymphocyte and its subsets should be routinely examined in all of the AA patients diagnosed so as to assess the indication and predict the effectiveness of immunosuppresive therapy.