Association Between Cytokine Gene Polymorphisms and Outcome of Hepatitis B Virus Infection in Southern Brazil

A number of studies have demonstrated associations between cytokine gene polymorphisms and outcome of hepatitis B virus (HBV) infection. However, no general consensus has been reached, possibly due to differences between ethnic groups. In this study, 345 individuals living in southern Brazil, including 196 chronic HBV carriers and 149 subjects who had spontaneously recovered from acute infection, were enrolled to evaluate the influence of cytokine gene polymorphisms on the outcome of HBV infection. Most participants were of European descent. Genotyping of IL2-330 G/T, IL4-589C/T, IL6-174 G/C, IL10-592C/A, IL10-1082 A/G, IL17A-197 G/A, IL17A-692 T/C, TNF-alpha-238 G/A, and TNF-alpha-308 G/A single nucleotide polymorphisms was performed by using the minisequencing (single base extension) method. By multivariable analysis, a statistically significant association was found between genotypic profile AA+GA in TNF-alpha-308 and chronic HBV infection (OR, 1.82; 95% CI, 1.01-3.27; P = 0.046). In southern Brazil, the carriers of the -308A allele in the TNF-alpha gene promoter have a moderately higher risk of becoming chronic carriers in case of HBV infection. In addition, patients with chronic active hepatitis B (n = 60) exhibited a decreased frequency (3.3%) of the TNF-238A allele when compared to that (14.8%) found among asymptomatic HBV carriers (n = 136), suggesting that this could be a protective factor against liver injury (OR, 0.17; 95% CI, 0.04-0.076; P = 0.023). (C) 2016 Wiley Periodicals, Inc.