Increasing evidence suggests that polymorphism of the interferon-gamma (IFN-γ) gene in the first intron at position +874 may be associated with chronic hepatitis B virus (HBV) infection and/or HBV clearance. However, the results of relevant studies have been inconsistent. To derive a more precise estimation of the association, we performed a meta-analysis. In total, 10 independent studies including 1661 chronic HBV-infected patients and 1142 controls were included in this meta-analysis. In studies following Hardy-Weinberg equilibrium (HWE), a significantly decreased risk of chronic HBV infection was associated with the IFN-γ + 874TT genotype in the overall population (TT vs AA: odds ratio (OR) = 0.714, 95% confidence interval (CI) = 0.526-0.969, P = 0.031) when compared with a spontaneously recovered population. Subgroup analysis by ethnicity revealed a similar association in Asian individuals (TT vs AA: OR = 0.706, 95% CI = 0.518-0.962, P = 0.028). Moreover, when compared with a healthy control group, the 874T allele was associated with a significant lower risk of chronic HBV infection in the overall populations (TA vs AA: OR = 0.439, 95% CI = 0.193-0.997, P = 0.049; TT + TA vs AA: OR = 0.475, 95% CI = 0.271-0.832, P = 0.009) and in Asian individuals (TA vs AA: OR = 0.862, 95% CI = 0.744-0.999, P = 0.048). In conclusion, the IFN-γ + 874TT genotype and 874T allele reduce the risk of chronic HBV infection in Asian individuals.
Keywords: IFN-gamma gene; chronic hepatitis B; meta-analysis; polymorphism.
© 2013 John Wiley & Sons Ltd.