Impact of IL10 polymorphism in chronic progression of hepatitis B virus infection

Abstract

Chronic infection with the hepatitis B virus (HBV) remains a major public health issue. Its progression depends on several factors, including immunogenetic factors. The aim of this study was to investigate the association between interleukin 10 gene (IL10) polymorphism and the progression of this infection. This retrospective case-control study involved 156 chronic HBV carriers (CHBV-C) and 174 healthy HBV-negative controls (HBsAg-). The analysis of IL10 promoter polymorphism was carried out using the TaqMan allele discrimination technique at two single nucleotide polymorphisms (SNPs), -592A>C (rs1800872) and -1082A>G (rs1800896), of the IL10 promoter. IL10 levels were measured using an in-house Enzyme-Linked Immunosorbent Assay (ELISA) for all patients chronically infected by HBV who had not yet received treatment. Chronic HBV infection (CBI) was present in 32% (n = 43) of cases, 37% (n = 51) had active chronic hepatitis (ACH), and 31% had complicated hepatitis. The analysis of allele polymorphism identified six genotypes: AA (14%), AC (43%), and CC (43%) for SNP-592A>C, and AA (41%), AG (45%) and GG (14%) for SNP-1082A>G. The only genotype that was substantially more common in CHBV-C patients was -1082/GG (OR=1.9; CI95%=[1,3.62]; p = 0.046). When compared to controls, the IL10 level was significantly higher in CBI patients (3.27 vs. 2.56 pg/ml;p = 0.002). Significantly higher IL10 levels were also linked to the genotypes -1082 GG (6.02 pg/ml;p = 0.04) and -592CC (3.73 pg/ml;p = 0.039). With the -592 AA genotype, this level was noticeably lower (1.35 pg/ml;p = 0.014). These findings support the hypothesis that the development of chronicity in HBV infection is linked to elevated IL10 levels and the -1082 GG genotype in the gene's promoter.