Association of -238G/A polymorphism of tumor necrosis factor-alpha gene promoter region with outcomes of hepatitis B virus infection in Chinese Han population

AIM:To clarify whether -238G/A polymorphism of tumornecrosis factor-α(TNF-α)gene promoter region wasassociated with outcomes of hepatitis B virus(HBV)infectionin Han population of northern China,and to analyze the gene-environment interaction between -238G/A polymorphism andcigarette smoking or alcohol consumption.METHODS:A case-control study was conducted to analyzethe association of TNF-α gene promoter polymorphism withHBV infection outcomes.A total of 207 patients with chronichepatitis B(HB)and 148 cases of self-limited HBV infectionfrom Ditan Hospital and Shunyi District Hospital in Beijing,respectively were recruited.History of smoking and alcoholdrinking was inquired by a questionnaire.The -238G/Apolymorphism of TNF-α gene promoter was genotyped bypolymerase chain reaction-restricted fragment lengthpolymorphism(PCR-RFLP).RESULTS:The frequencies of GG and GA genotypes were98.07% and 1.93% in chronic HB patients and 93.24% and6.76% in self-limited HBV infection individuals,respectively(X~2=5.30,P=0.02).The frequency of G allele was significantlyhigher in patients with chronic HB that in individuals withself-limited HBV infection(99.03% vs 96.62%,X~2=5.20,P=0.02).Only modestly increased risk of onset of chronicHB was found in smokers(OR=1.40,95% CI: 0.87-2.28,P=0.14)and drinkers(OR=1.26,95%CI:0.78-2.05,P=0.32).There was a positive interaction between genotype GG andcigarette smoking with an interaction index(Ⅱ)of 2.95,oralcohol consumption with an Ⅱ of 1.64. CONCLUSION:The -238G/A polymorphism of TNF-α genepromoter region is independently associated with differentoutcomes of HBV infection.