In vivo liver expression of TLR2, TLR3 and TLR7 in chronic hepatitis C

The role of innate immune response mediated by Toll-like receptors in HCV infection, is not yet well understood and there is a lack of data regarding liver tissue expression of these molecules in chronic hepatitis C (CHC). Our study is aimed to investigate ex vivo, liver expression of TLR2, TLR3 and TLR7, which are more involved in the immune-pathogenesis of CHC, and to explore possible correlations with features of disease. We obtained liver biopsies and collected peripheral blood mononuclear cells (PBMC) from 23 consecutive patients with CHC and from 6 patients of control, without liver disease, undergoing surgery for cholecystectomy. The levels of TLRs mRNA in the samples were determined using a real-time reverse transcription quantitative PCR (RT-qPCR). We found a significant high expression of TLR3 in the liver of CHC patients respect to controls (also higher than expression in the PBMC). Conversely no differences emerged in the TLR2 and TLR7 levels between cases and controls. Also we found a correlation of TLR2 and TLR7 levels with the grade of necro-inflammation in the liver. Furthermore TLR7 hepatic levels resulted related to a more advanced stage of liver fibrosis. Ours is the first study to provide data on tissue expression of TLRs during chronic hepatitis C and we believe that it could lead to a better understanding of the role of these molecules in the HCV-mediated liver damage.