Abnormal activation of T lymphocytes in patients with aplastic anemia and myelodysplastic syndrome treated with cyclosporin A

To investigate the expression of the early activation marker of T cells(CD69) on CD4+ and CD8+ lymphocytes in peripheral blood in patients with aplastic anemia(AA) and myelodysplastic syndrome(MDS) before and after cyclosporin A(CsA) therapy and the pathophysiological significance of the changes in CD69 expression in different T cell populations of both pre- and post-culture in vitro, the whole blood cell culture procedure was applied to activate T lymphocytes by PHA(20 μg/ml) in vitro. The expression rates of CD69 on CD4+ and CD8+ lymphocytes at 0 h and 4 h after culture were analyzed by two-color flow cytometry. It was found the expression rates of CD69 of CD4+ and CD8+ cells in patients with newly diagnosed SAA and MDS-RA+MDS-RAS and the expression rates of CD69 on CD8+ cells in patients with CAA and RAEB+RAEB-T increased before PHA stimulation. The expression rates of CD69 of CD4+ and CD8+ cells in patients with AA and MDS elevated significantly after PHA stimulation. CD69 expression on CD4+ cells was much higher than that on CD8+ cells after stimulation in patients with AA. The expression rates of CD69 of CD4+ and CD8+ cells in patients with SAA and the expression rates of CD69 of CD8+ cells in patients with CAA after CsA therapy before PHA stimulation decreased remarkably compared with those before therapy. CD69 expression on CD4+ cells and CD8+ cells after PHA stimulation in patients with AA after CsA therapy decreased significantly compared with those before therapy. CD69 expression on CD4+ and CD8+ cells before and after PHA stimulation in patients with AA could be cured before CsA therapy increased remarkably and decreased significantly after therapy. CD69 expression on CD4+ cells before and after stimulation in patients with newly diagnosed AA were much higher than those in MDS. These results suggested that the increased early activation and activated potentials of T lymphocytes might play a major role in the pathogenesis of AA and MDS. CsA might inhibit T cells early activation in AA.