Effect of telbivudine therapy on the cellular immune response in chronic hepatitis B

Weak T-cell reactivity to the hepatitis B virus (HBV) is believed to be the dominant cause of chronic HBV infection. Several lines of experimental evidence suggest that treatment with telbivudine increases the rate of HBV e antigen (HBeAg) loss, undetectable HBV DNA, and normalization of serum alanine aminotransferase (ALT) in chronic hepatitis B patients (CHB). However, it is still unclear how early antiviral therapy affects cellular immune responses during sustained telbivudine treatment. In order to investigate this issue, we measured detailed prospective clinical, virological, and biochemical parameters, and we examined the frequency of T cell subgroups as well as the ability of peripheral blood mononuclear cells (PBMC) to respond to stimuli at five protocol time points for 51 CHB patients who received telbivudine therapy for one year. The preliminary data from this study revealed that effective-treated patients showed an increased frequency of peripheral blood CD4(+)T lymphocytes, an augmented proliferative response of HBV-specific T-cells to the hepatitis B core antigen (HBcAg), and the induction of cytokines, such as interferon gamma (IFN-γ), tumour necrosis factor alpha (TNF-α) release at the site of infection compared to non-responsive patients. Enhanced HBV-specific T-cell reactivity to telbivudine therapy, which peaked at treatment week 12, was confined to a subgroup of effective-treated patients who achieved greater viral suppression.