The study aims to understand the role of the Th1/Th2 polarization in the pathogenesis of AA. PBMNCs from patients with CAA and the healthy controls with PMA were studied, ionomycin and intracellular protein transport inhibitor BFA in vitro were detected the surface markers CD3, CD4, CD8 and HLA-DR as well as the intracellular productions of IFN-gamma and IL-4 with direct immunofiuorescent method. We found that both CD3/CD4 and CD4/CD8 were decreased in the CAA, while CD3/CD8 and CD8/HLA-DR were increased. These results implied that IFN-gamma was increased as activity of cytokine. Furthermore, the proportion of Th1 cells in PBMNCs was significantly higher in patients with CAA, while the proportion of Th2 cells had no significant difference, indicating that Th1 cells play a dominant role in patients with CAA. Correlation analysis confirmed that Th1 cells was positively correlated with CD3(+)CD8(+) cells, but negatively correlated with the relative value of reticulocytes and ANC, further suggesting that Th1 cells play an important role in the pathogenesis of CAA. The ratio of Th1 cells was correlated with blood reticulocyte and neutrophils and minus number, and the Th1/Th2 ratio biases indicated that the imbalance between Th1 and Th2 cells plays a crucial role in the pathogenesis of CAA. Artificial restoration of the balance between Th1 and Th2 cells may be a new strategy for the treatment of chronic aplastic anemia.
