A possible role for NKT-like cells in patients with chronic hepatitis B during telbivudine treatment

Natural killer T-like (NKT-like) cells are a source of different pro-inflammatory cytokines and therefore may be involved in inflammatory processes. However, little is known about NKT-like cells during antiviral therapy. In this study, we observed significantly higher numbers of CD3+CD56+ cells in patients with chronic hepatitis B (CHB) than healthy controls. Importantly, CD3+CD56+ NKT-like cells markedly decreased during telbivudine treatment in patients with CHB, and a positive correlation between NKT-like cell frequency and the serum HBV DNA level was observed during early antiviral therapy. Interestingly, NKT-like cell frequency significantly reduced in well-responders at week 12 of telbivudine therapy compared to baseline, but did not significantly change in non-responders after treatment. Previous studies have shown that interleukin (IL)-17 plays a role in the pathogenesis of CHB. Serum IL-17 levels reduced significantly during early antiviral therapy, however, interferon (IFN)-γ, IL-6 and tumor necrosis factor (TNF)-α levels did not change significantly. A positive correlation was observed between the NKT-like cell frequency and serum IL-17 level in CHB patients, and NKT-like cells isolated from patients with CHB secreted substantial amounts of IL-17 in vitro. These results suggest that the NKT-like cell frequency may be one of useful immunologic marker for evaluating the efficacy of anti-HBV therapy, and that NKT-like cells are also an important source of IL-17 (in addition to conventional T cells) in patients with CHB.