Restored circulating invariant NKT cells are associated with viral control in patients with chronic hepatitis B.

Invariant NKT (iNKT) cells are involved in the pathogenesis of various infectious diseases. However, their role in hepatitis B virus (HBV) infection is not fully understood, especially in human species. In this study, 35 chronic hepatitis B (CHB) patients, 25 inactive carriers (IC) and 36 healthy controls (HC) were enrolled and the proportions of circulating iNKT cells in fresh isolated peripheral blood mononuclear cells (PBMC) were detected by flow cytometry. A longitudinal analysis was also conducted in 19 CHB patients who received antiviral therapy with telbivudine. Thereafter, the immune functions of iNKT cells were evaluated by cytokine secretion and a two-chamber technique. The median frequency of circulating iNKT cells in CHB patients (0.13%) was lower than that in HC (0.24%, P = 0.01) and IC (0.19%, P = 0.02), and increased significantly during antiviral therapy with telbivudine (P = 0.0176). The expressions of CC chemokine receptor 5 (CCR5) and CCR6 were dramatically higher on iNKT cells (82.83%±9.87%, 67.67%±16.83% respectively) than on conventional T cells (30.5%±5.65%, 14.02%±5.92%, both P<0.001) in CHB patients. Furthermore, iNKT cells could migrate toward the CC chemokine ligand 5. Patients with a high ratio (≥1.0) of CD4-/CD4+ iNKT cells at baseline had a higher rate (58.33%) of HBeAg seroconversion than those with a low ratio (<1.0, 0%, P = 0.0174). In conclusion, there is a low frequency of peripheral iNKT cells in CHB patients, which increases to normal levels with viral control. The ratio of CD4-/CD4+ iNKT cells at baseline may be a useful predictor for HBeAg seroconversion in CHB patients on telbivudine therapy.