Objective To investigate the compositions of Th1/Th2/Th3 cells in chronic hepatitis B viru s (HBV)-infected individuals by determining the expression of interleukin-4 (I L-4), inetrferon-γ (IFN-γ), and transform growth factor-β (TGF-β) in si ngle CD4 + T cells isolated from peripheral blood mononuclear cells (PBMCs) and the role of polarized Th cell populations in chronic HBV-infection was discuss ed. Methods PBMCs from chronically infected HBV individuals were isolated, stimulated by PMA /Ionomycin/Monensin, and IL-4, IFN-γ and TGF-β production by CD4 + T cells was determined by using fluorescence activated cell sorter (FACS) analysis.Results The percentage of IFN-γ-producing T cells, IL-4-producing T cells and TGF- β-producing T cells ranged from 2.3%-18.6%, 1.1%-8.7% and 0.7%-7.1% resp ectively in CD4 + T cells from non-infected individuals. Most of CD4 + T cel ls from PBMCs in chronically infected HBV individuals were Th0 cells. The propo rtion of Th1 cells increased significantly with hepatic inflammatory activity, and in the active period of chronic hepatitis B infection were higher than those in the non-active period ( P < 0.05). Th2 cell percentage in CD4 + T c ells from HBV-infected individuals did not differ significantly ( P >0.05), but were higher than that from controls ( P < 0.05). Th3 cell percentage in CD4 + T cells from asymptomatic carrier (AsC) group was higher than that in the chronic hepatitis B (CHB) and control groups ( P <0.05). Conclusions Th1 phenotype cytokines were positively correlated with hepatic inflammatory act ivity in chronic hepatitis B and Th2 cells may be associated with the persistenc e of HBV infection. Th3 cells cooperating with Th2 cells can negatively regulat e immune responses and may be associated with the immune tolerant state of chron ic HBV infection. Objective To investigate the compositions of Th1 / Th2 / Th3 cells in chronic hepatitis B viru s (HBV) -infected individuals by determining the expression of interleukin-4 (I L-4), inetrferon-γ Growth factor-β (TGF-β) in si ngle CD4 + T cells isolated from peripheral blood mononuclear cells (PBMCs) and the role of polarized Th cell populations in chronic HBV-infection was discuss ed. Methods PBMCs from chronically infected HBV individuals were isolated, stimulated by PMA / Ionomycin / Monensin, and IL-4, IFN-γ and TGF-β production by CD4 + T cells was determined by using fluorescence activated cell sorter (FACS) analysis. Results The percentage of IFN- γ-producing T cells, IL-4-producing T cells and TGF-β-producing T cells ranged from 2.3% -18.6%, 1.1% -8.7% and 0.7% -7.1% respctively in CD4 + T cells from non-infected individuals. Most of CD4 + T cel ls from PBMCs in chronically infected HBV individuals were Th0 cells. The propo rtion of Th1 cells increased significantly with hepatic inflammatory activity, and in the active period of chronic hepatitis B infection were higher than those in the non-active period (P <0.05). Th2 cell percentage in CD4 + T c ells from HBV-infected individuals did not differ significantly (P> 0.05), but were higher than that from controls (P <0.05). Th3 cell percentage in CD4 + T cells from asymptomatic carrier (AsC) group was higher than that in the chronic hepatitis B (CHB) and control groups P <0.05). Conclusions Th1 phenotype cytokines were positively correlated with hepatic inflammatory act ivity in chronic hepatitis B and Th2 cells may be associated with the persistenc e of HBV infection. Th3 cells cooperating with Th2 cells can negatively regulat e immune responses and may be associated with the immune tolerant state of chron ic HBV infection.