Intrahepatic <i>TLR3</i> and <i>IFNL3</i> Expressions Are Associated with Stages of Fibrosis in Chronic Hepatitis C

An inefficient immune response against the hepatitis C virus (HCV), combined with viral evasion mechanisms, is responsible for the chronicity of infection. The need to evaluate the innate mechanisms of the immune response, such as TLR3 and IFN-λ3, and their relationship with the virus–host interaction is important for understanding the pathogenesis of chronic hepatitis C. The present study aimed to investigate the gene expressions of <i>TRL3</i> and <i>IFNL3</i> in liver tissue, seeking to evaluate whether these could be potential biomarkers of HCV infection. A total of 23 liver biopsy samples were collected from patients with chronic HCV, and 8 biopsies were collected from healthy control patients. RNA extraction, reverse transcription and qPCR were performed to quantify the relative gene expressions of <i>TLR3</i> and <i>IFNL3</i>. Data on the viral load; AST, ALT, GGT and AFP levels; and the viral genotype were collected from the patients′ medical records. The intrahepatic expression of <i>TLR3</i> (<i>p</i> = 0.0326) was higher in chronic HCV carriers than in the control group, and the expression of <i>IFNL3</i> (<i>p</i> = 0.0037) was lower in chronic HCV carriers than in the healthy control group. The expression levels of <i>TLR3</i> (<i>p</i> = 0.0030) and <i>IFNL3</i> (<i>p</i> = 0.0036) were higher in the early stages of fibrosis and of necroinflammatory activity in the liver; in contrast, <i>TLR3</i> and <i>IFNL3</i> expressions were lower in the more advanced stages of fibrosis and inflammation. There was no correlation between the gene expression and the serum viral load. Regarding the initial METAVIR scale scores, liver transaminase levels were lower in patients with advanced fibrosis when correlated with <i>TLR3</i> and <i>IFNL3</i> gene expressions. The results suggest that in the early stages of the development of hepatic fibrosis, TLR3 and IFN-λ3 play important roles in the antiviral response and in the modulation of the tolerogenic liver environment because there is a decrease in the intrahepatic expressions of <i>TLR3</i> and <i>IFNL3</i> in the advanced stages of fibrosis, probably due to viral evasion mechanisms.