['To explore the relationship between the expression of TLR9 and the levels of CD38, HLA-DR and CD95 on peripheral blood mononuclear cells (PBMCs) of chronic hepatitis B virus (HBV) infected patients.', '70 chronic HBV infected patients and 12 healthy donors were enrolled in this study, and density gradient centrifugation was used to isolate PBMCs from peripheral blood with EDTA for anticoagulation. Flow cytometry was used to detect the levels of TLR9, CD38, HLA-DR and CD95 on PBMCs.', 'Compared to the healthy donors, chronic HBV infected patients with low viral load or high viral load had significantly higher levels of TLR9, HLA-DR and CD95 on PMBCs. Furthermore, the co-expression rates of TLR9 and CD38, HLA-DR, CD95 on PBMCs were obviously higher than those of the healthy donors. Correlation analysis showed that the expression of TLR9 was positively correlated with CD38 (r=0.345), HLA-DR (r=0.334), CD95 (r=0.227) on PBMCs in the patients with chronic HBV infection.'] Is [ TLR9 expression positively correlated with the levels of CD38 , HLA-DR and CD95 on peripheral blood mononuclear cells in chronic HBV infected patients ]?