Association between Toll-Like Receptor 3 (TLR3) rs3775290, TLR7 rs179008, TLR9 rs352140 and Chronic HCV

Background: Inconsistent results were reported on the association of TLRs polymorphisms with the risk of HCV infection and HCV-related diseases.

Objective: to assess the relation between TLR3 rs3775290, TLR7 rs17900 and TLR9 rs352140 SNPs and chronic HCV in the Egyptian cohort and to study their relation to interferon response.

Methods: TLR3 rs3775290, TLR7 rs179008 and TLR9 rs352140 gene polymorphisms were typed by RFLP for 100 patients with chronic HCV and 25 with HCC in addition to 100 healthy controls.

Results: A significant higher frequency has been found for the CT genotype of TLR3 rs3775290 in chronic HCV infection (p < 0.001) and CC genotype and the combined genotype CC-AT-GA ♀ in controls (p < 0.001). Non-significant associations have been found for studied SNPs and HCC and response to interferon and also the viral load or the degree of fibrosis, however, the higher HCV viral load and the higher grade of fibrosis were associated with treatment failure (p < 0.001).

Conclusion: The heterozygous CT genotype of TLR3 rs3775290 may be a susceptibility risk factor for chronic HCV infection and the homozygous CC and the combined CC-AT-GA ♀ genotypes may be protective. The HCV viral load and the grades of liver fibrosis could be considered a risk factor for interferon treatment failure. It seems that the studied SNPs have no role in HCC development or failure of treatment. However, the small sample size is a limiting factor of the present study when interpreting the negative associations and that the current used cohort does not permit such conclusion.

Abbreviations: cHCV=chronic Hepatitis C virus, HCC=hepatocellular carcinoma, TLR=Toll like Receptor, RFLP=Restriction Fragment Length Polymorphism, SNP=Single Nucleotide Polymorphism, IFN-α= interferon alpha