Strong association of functional polymorphism in IL-12B with susceptibility to chronic hepatitis B in Tunisia

Background The chronicity or clearance of hepatitis B virus (HBV) infection depends on viral and genetic variables. The immune response against HBV is thought to be responsible for viral persistence or clearance. Cytokines such as interleukin 1-2B (IL1-2B) involved in the T-helper 1 system are key mediators in the defence mechanisms against viral infection and play a role in the regulation of HBV clearance during infection. We aimed to examine whether the polymorphic variant TaqI polymorphism in the 3 '-untranslated region (3 '-UTR; rs3212227) suspected to modulate interleukin-levels of IL-12B has an influence on the risk of development of chronicity after HBV exposure. Methods Genotyping was performed by the polymerase chain reaction-restriction fragment length polymorphism method for 236 patients with chronic hepatitis B (CHB) and 240 controls from different cities of Tunisia recruited in the Pasteur Institute of Tunisia between January 2017 and December 2018. Results We found that the IL-12B polymorphism was associated with a significantly increased risk of CHB in patients (p = 1 x 10(-3); chi(2) = 10.31 and odds ratio [OR] = 2.14; 95% confidence interval [CI] = 1.30-3.52) when AC/CC variant genotypes were compared with the wild-type AA homozygote. Statistical significance was found when CHB-males were compared with CHB-females (p = 2 x 10(-7); chi(2) = 26.62 and p = 1 x 10(-3); chi(2) = 10.36, for genotypic and allelic frequencies, respectively). Also, CHB-patients carrying C-allele less than 50-years were at an increased risk of developing chronic HBV infection than patients more than 50-years (p = 6.1 x 10(-5); chi(2) = 16.07). Conclusions These results suggest that the C-allele would affect susceptibility to chronicity after HBV exposure in Tunisian patients especially for males less than 50-years. Age and sex have an influence on this polymorphism in CHB Tunisian patients.

Automated summary

The study revealed that the IL-12B gene polymorphism is significantly associated with an increased risk of chronic hepatitis B (CHB) in patients, particularly in males under the age of 50.