Serum IL-6 level may differentiate immune inactive phase from other phases in patients with chronic hepatitis B virus infection

Abstract

Abstract Background and Aims Previous studies have found that serum level of IL-6 was increased in HBV-infected patients. Here we evaluate the impact of IL-6 levels according to the natural history of chronic hepatitis B(CHB) infection. Method Patients(n=71) with hepatitis B virus(HBV) were enrolled between September 2016 and Feb. 2018. Treatment-naïve chronic HBV carries were recruited. IFN-γ, TNF-α, IL-2, IL-6, and IL-17A were measured by a cytometric bead assay according to manufacturer’s instructions. Soluble PD-1 and soluble CD14 were made by the enzyme linked immunosorbent assay (ELISA) technique. The assay procedures were followed according to the manufacturer’s instructions. We studied patients with immune inactive phase (HBV DNA< 1,000 copies/ml, anti-HBe + and normal ALT, n=22), immune tolerant phase (HBV DNA > 10,000 copies/ml, HBeAg + and normal ALT, n=36), and immune active phase (elevated ALT and HBV DNA>10,000 copies/ml, n=13). Results Serum IL-6 levels in patients with immune inactive phase were significantly lower than patients with immune tolerant and immune active phases (267.3±245.6 pg/mL vs. 620.2±207.8 pg/mL and 1,815±803.2) (p<0.001). Serum TNF-α levels in patients with immune inactive phase was slightly lower than patients with immune tolerant and immune active phases (3.36±4.40 pg/mL vs. 8.74±12.91 pg/mL and 111.9±377.4) (p=0.079). However, other cytokines (serum IL-2, IL-17A, IFN-γ), soluble CD 14, and soluble PD-1 levels might not be significantly related to the natural history of CHB phase. Conclusion These results demonstrate the potential to apply serum IL-6 as a biomarker for differentiating immune inactive phase from other phases in patients with chronic HBV infection.