Changes of hepatitis B core antigen-specific cytotoxic T lymphocytes in chronic hepatitis B patients during antiviral treatment and relapse after withdrawal of treatment / 中华传染病杂志

ABSTRACT

Objective To explore the potential mechanism of severe liver injury shortly after withdrawal of antiviral therapy in chronic hepatitis B (CHB) patients.Methods Forty-nine patients with chronic hepatitis B virus (HBV) infection from the Department of Infectious Diseases of the First Affiliated Hospital of Nanchang University and 8 healthy volunteers from August 2014 to March 2015 were included in this study.All of them were human leukocyte antigen (HLA)-A2-positive.CHB patients were classified into three groups,including 15 cases in immune-tolerance group,20 cases in sustained antiviral treatment group,and 14 cases in recurrence of drug withdrawal group.The frequency of peripheral HLA-A0201-restricted hepatitis B core antigen (HBcAg)18-27 pentamer complex specific CD8+ T cells in CHB patients was analyzed by flow cytometry.Enzyme linked immunospot assay(ELISPOT) was used to detect interferon-gamma (IFN-γ) and tumor necrosis factor-α (TNF-α) secretions of HBcAg18-27-specific CD8+ T cells.The experimental data were analyzed using non-parametric U tests.Results In healthy control group,immune-tolerance group,sustained antiviral treatment group and recurrence of drug withdrawal group,the frequencies of HBcAg-specific CD8+T cells were (0.17 ± 0.16) ％,(1.46±0.72)％,(3.24± 1.60)％ and (4.67±2.43)％,respectively.Compared with healthy control group,the difference were all statistically significant in the three groups (Z=-3.583,-4.018 and-3.823,respectively;all P＜0.01).The frequencies of HBcAg-specific CD8+T cells in immune tolerance group or recurrence of drug withdrawal group were both significantly different from that in sustained antiviral therapy group (Z=-3.400 and-2.030,respectively;both P＜0.05).The difference between immune-tolerance group and recurrence of drug withdrawal group was also significant (Z =-3.230,P＜0.01).The secretion levels of IFN-γ of HBcAg-specific CD8+T cells in healthy control group,immune-tolerance group,sustained antiviral treatment group and recurrence of drug withdrawal group were2 (0-6),16 (2-53),106 (14-254) and 156 (28-395) spot forming cell (SFC)/106 peripheral blood mononuclear cell (PBMC),respectively.The differences between healthy control group and immune-tolerance group,sustained antiviral treatment group or recurrence of drug withdrawal group were all statistically significant (Z=-3.585,-4.069 and-3.824,respectively;all P＜0.01).The IFN-γ level of HBcAg-specific CD8+ T cells in recurrence of drug withdrawal group was significantly higher than that in sustained antiviral therapy group (Z=-2.205,P=0.027),and that in sustained antiviral therapy group was significantly higher than that in immune-tolerance group (Z=-4.700,P＜ 0.01).The TNF-α levels secreted by HBcAg-specific CD8+ T cells in each group were 2 (0-5),16 (2-32),112 (15-283),and 195 (55-537) SFC/106PBMC,respectively.The differences between healthy control group and immune-tolerance group,sustained antiviral treament group or recurrence of drug withdrawal group were all statistically significant (Z=-3.619,-4.069 and-3.824,respectively;all P＜0.01).The TNF-α level secreted by HBcAg-specific CD8+T cells in recurrence of drug withdrawal group was significantly higher than that in sustained antiviral therapy group (Z=-2.449,P=0.014),and that in sustained antiviral therapy group was significantly higher than that in immune-tolerance group (Z=-4.350,P＜0.01).Conclusions The changes of frequency and immune function of HBcAg-specific CD8+T cells in CHB patients may be one of the reasons causing severe liver damage after irregular withdrawal of nucleoside analogues.