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

IL-6 gene polymorphism predicts PEGylated IFN-α treatment response in hepatitis B surface antigen-positive chronic hepatitis B patients

Background: Genetic polymorphism can affect the response to antiviral therapy of chronic hepatitis B (CHB) patients. Objective: The study examined the genetic association of the IL-6 rs1800796 polymorphism with PEGylated IFN-α (PegIFN-α) treatment response in hepatitis B surface antigen (HBsAg)-positive CHB patients. Methods: Direct sequencing was done for the genotyping of the rs1800796 polymorphism in the serum of CHB patients. Results: More patients with combined response (n = 95) carried IL-6 rs1800796 GC genotypes, while CC genotype carriers possessed reduced HBeAg seroconversion rate and high values of hepatitis B virus DNA. Baseline HBsAg and HBeAg and IL-6 rs1800796 CC genotype were independently related to PegIFN-α treatment response. Conclusion: Detection of the IL-6 rs1800796 genotype in CHB patients may have potential guiding significance for PegIFN-α response.

A Meta-Analysis of the Association Between Genetic Polymorphisms in IL-12, IL-17, and IL-21 and Risk of Hepatitis B Virus Infection

Cytokine imbalance is an important feature in the occurrence and outcome of hepatitis B virus (HBV). Single nucleotide polymorphisms (SNPs) within cytokine genes may affect the protein expression and eventually contribute to the susceptibility of HBV infection. The association between interleukin (IL)-12, IL-17, or IL-21 and the risk of HBV infection has been extensively studied, but yielding equivocal results. The aim of this meta-analysis was to determine the impact of SNPs in IL-12, IL-17, and IL-21 on the risk of HBV infection. We retrieved studies evaluating whether SNPs in IL-12, IL-17, and IL-21 influenced HBV infection from electronic databases, including PUBMED, Web of Science, EBOCO, OVID, and Embase. Summarized odds ratios (ORs) and confidence intervals (CIs) were calculated using STATA software. Under a homozygous comparison, the IL-12A rs568408 was associated with an increased risk of HBV infection in both overall analysis (OR = 1.68, 95% CI, 1.12-2.53) and Caucasians (OR = 1.80, 95% CI, 1.14-2.84). Under a dominant genetic model, the similarly higher risk was also observed in overall analysis (OR = 3.62, 95% CI, 3.08-4.24), Caucasians (OR = 3.29, 95% CI, 2.67-4.05), high-quality studies (OR = 3.29, 95% CI, 2.61-4.14), and low-quality studies (OR = 3.95, 95% CI, 3.17-4.93). Although no significant association was observed between IL-17A rs2275913 and the risk of HBV infection in overall comparison, subgroup analysis revealed that the IL-17A rs2275913 AA genotype was associated with a reduced risk in Asians (OR = 0.72, 95% CI, 0.57-0.91) and high-quality studies (OR = 0.71, 95% CI, 0.55-0.92). However, no significant association of IL12B rs3212227, IL-17A rs2275913, IL-21 rs2221903, and rs907715 with HBV infection was observed. In conclusion, we provide evidence that IL-12A rs568408 was associated with an increased risk of HBV infection and IL-17A rs2275913 AA genotype was a protective factor against HBV infection in Asians.

Cytokines and Chemokines in HBV Infection

Chronic hepatitis B virus (HBV) infection remains a leading cause of hepatic inflammation and damage. The pathogenesis of chronic hepatitis B (CHB) infection is predominantly mediated by persistent intrahepatic immunopathology. With the characterization of unique anatomical and immunological structure, the liver is also deemed an immunological organ, which gives rise to massive cytokines and chemokines under pathogenesis conditions, having significant implications for the progression of HBV infection. The intrahepatic innate immune system is responsible for the formidable source of cytokines and chemokines, with the latter also derived from hepatic parenchymal cells. In addition, systemic cytokines and chemokines are disturbed along with the disease course. Since HBV is a stealth virus, persistent exposure to HBV-related antigens confers to immune exhaustion, whereby regulatory cells are recruited by intrahepatic chemokines and cytokines, including interleukin-10 and transforming growth factor β, are involved in such series of causal events. Although the considerable value of two types of available approved treatment, interferons and nucleos(t)ide analogues, effectively suppress HBV replication, neither of them is sufficient for optimal restoration of the immunological attrition state to win the battle of the functional or virological cure of CHB infection. Notably, cytokines and chemokines play a crucial role in regulating the immune response. They exert effects by directly acting on HBV or indirectly manipulating target immune cells. As such, specific cytokines and chemokines, with a potential possibility to serve as novel immunological interventions, combined with those that target the virus itself, seem to be promising prospects in curative CHB infection. Here, we systematically review the recent literature that elucidates cytokine and chemokine-mediated pathogenesis and immune exhaustion of HBV infection and their dynamics triggered by current mainstream anti-HBV therapy. The predictive value of disease progression or control and the immunotherapies target of specific major cytokines and chemokines in CHB infection will also be delineated.