Effect of IL28B genotype on hepatitis B and C virus infection.

Genetic factors play a major role for treatment response and disease progression of chronic hepatitis B (HBV) and C virus (HCV) infection. In 2009 a genome-wide association study (GWAS) identified a single nucleotide polymorphism near the IL28B gene that was associated with treatment-induced viral clearance in chronic HCV infection treated with pegylated interferon-α (PEG-IFN) and ribavirin (RBV). Further, another GWAS found an association between IL28B genotype and spontaneous viral clearance in acute HCV infection. The effect on sustained viral response (SVR) could also be observed in patients receiving a triple-therapy with a direct antiviral agent (DAA) combined with PEG-IFN/RBV. In the era of all-oral interferon-free treatment regimens with the combination of different DAAs-with SVR rates exceeding 90%-the effect of IL28B was blunt. In contrast, in HBV several retrospective studies yielded conflicting results of the association of IL28B with PEG-IFN-induced treatment response.