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

To study the role of immunological factors in the pathogenesis of aplastic anemia(AA).

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.

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.

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.