Liver tissue samples were obtained from a broad range of patients with different disorders including minimal or no hepatic disease, liver diseases of non-viral etiology, chronic hepatitis B and chronic hepatitis C. In liver samples from patients with chronic hepatitis C, we additionally determined hepatic viral loads and IL28A/B and IL29 mRNA expression and tested whether the relationship between IFNL4 and ISG activation found in vitro is also existent in vivo. Here, IFNL1 is linked to chronic hepatitis C virus infection.