Association of TNF-alpha promoter polymorphisms with the outcomes of hepatitis B virus infection in Chinese Han population

Host genetic factors and environment factors including hepatitis B virus (HBV) genotypes are widely studied for the different outcomes of HBV infection. Recent studies suggest that tumour necrosis factor-alpha (TNF-alpha) plays a pivotal role in the viral clearance and host immune response to HBV, and the capacity for TNF-alpha production in individuals is influenced by a major genetic component. In this study, we aimed to explore whether the single-nucleotide polymorphisms (SNPs) of TNF-alpha promoter are associated with the outcomes of HBV infection in the Chinese Han population. One hundred and forty-three spontaneously recovered HBV subjects and 196 chronic hepatitis B patients were recruited in this case-control study in the Beijing area of China. Polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) and sequence-specific primer-PCR (SSP-PCR) were used to detect the SNPs of five sites in the TNF-alpha promoter (-238G/A, -308G/A, -857C/T, -863C/A, -1031T/C). The frequency distributions of genotypes and haplotypes in two groups were analysed by EPI and EH programs. The presence of the -238GG genotype was significantly correlated with persistence of HBV infection (OR = 4.08, P = 0.02), and -857TT genotype appeared in relation to the spontaneous clearance of HBV (OR = 0.47, P = 0.03). Frequency of haplotype GGCCT (-238/-308/-857/-863/-1031) in the chronic HB group was significantly lower than that in spontaneously recovered group (P = 0.03), and frequencies of haplotypes GGCAT and GGTAT in the chronic HB group were significantly higher than those in the spontaneously recovered group (P = 0.0001, P = 0.0004). In conclusion, TNF-alpha promoter polymorphisms are independently associated with different outcomes of HBV infection.