Abstract: Objective The aim of this study was to investigate the expression of lectin-like receptor G1 (KLRG1) in natural killer cells of patients with chronic hepatitis B (CHB). Methods 120 patients with CHB and 120 healthy persons were included in this study, and the percentage of NK cells, KLRG1⁺ NK cells and interferon-γ secreting NK cells from peripheral blood mononuclear cells (PBMCs) were detected by flow cytometry, and the cytotoxicity of NK cells to LX-2 cells was also assayed. Results The percentage of NK cells in peripheral blood of patients with CHB was (17.2±7.7)%, significantly higher than [(11.3±6.9)%, t=9.85, P=0.01], the percentage of KLRG1⁺NK cells was (52.2±20.3)%, much higher than [ (30.3 ±16.9)%, t=6.57, P=0.01] and the percentage of interferon-γ secreting NK cells was(14.6±3.8)%, significantly lower than 【(42.5±9.5)%, t=11.24,P=0.01】 in the control; the expression of CD38, CD69, HLA-DR and TRAIL in NK cells in patients with CHB intensified greatly as compared to those in control (P=0.012, P=0.015, P=0.025, P=0.019);the early apoptosis rate of LX-2 cells in patients with CHB was 11.5% (6.6%-13.7%), and the late apoptosis rate was 7.2% (5.1%-8.5%), decreased greatly as compared to 15.4% (11.5%-24.3%) or 13.5% (8.1%-20.4%) in the control (U=6.50, P=0.025; U=2.02,P=0.002) . Conclusion The expression of KLRG1 in NK cells in patients with CHB intensifies, and the reduced secretion of INF-gamma might decrease the immune functions and lead to chronic infections.

Key words: Hepatitis B, Natural killer cells, Killer cell Lectin-like receptor subfamily G member, Cytotoxicity