Telbivudine decreases proportion of peripheral blood CD4+CD25+CD127low T cells in parallel with inhibiting hepatitis B virus DNA

Regulatory T cells (Treg) have significant roles in the immunopathology of patients with chronic hepatitis B (CHB) and exhibit an evident correlation with antiviral immunity when antiviral therapy is applied. In order to investigate how circulating Tregs are affected by telbivudine treatment and its significance in patients with CHB, peripheral blood mononuclear cells (PBMCs) were isolated and the proportions of circulating cluster of differentiation (CD)4+CD25+CD127low and CD8+CD25+ T cells of CHB patients prior to and during the three or six months of treatment were assessed and detected by flow cytometric analysis. The levels of forkhead/winged helix transcription factor (Foxp3) mRNA were also quantified using quantitative polymerase chain reaction. A significantly higher percentage of CD4+CD25+CD127low and CD8+CD25+ T cells in the PBMCs of patients with CHB were identified compared with that of healthy individuals. Patients with CHB also demonstrated significantly higher levels of Foxp3 mRNA compared with that of healthy individuals. Following six months of telbivudine treatment, the proportion of circulating CD4+CD25+CD127low and CD8+CD25+ T cells and the relative levels of Foxp3 mRNA in patients with CHB was comparable to the proportion in healthy individuals. The proportions of circulating peripheral blood CD4+CD25+CD127low T cells were paralleled with its HBV DNA inhibition. The results of the present study indicate that telbivudine treatment reduces HBV DNA levels rapidly and indirectly affects the immune system by downregulating the proportion of circulating Treg markedly, which may be beneficial to restore the antiviral immune response.