Polymorphisms in the interleukin-10, tumor necrosis factor-α, and transforming growth factor-β1 genes in chronic hepatitis C patients treated with interferon and ribavirin

Background/Aims: In hepatitis C infection, the production of inappropriate cytokine levels appears to contribute to viral persistence and to affect the response to antiviral therapy. Additionally, polymorphisms in the cytokine genes may affect the production of the cytokines. In this study, we determined the frequency of the genotypes associated with polymorphisms of the interleukin-10 and tumor necrosis factor-α gene promoters, and transforming growth factor-β1 gene leader sequence, and investigated their association with clinical features and the response to interferon-α and ribavirin therapy in chronic hepatitis C infection. Methods: Genomic DNA from 80 patients and 37 racially matched healthy controls was studied by polymerase chain reaction and direct automated sequencing. Results: The interleukin-10 −1082 G/G genotype was identified more frequently in patients than in controls (P=0.048). The transforming-growth factor-β1 +29 (codon 10) C/C genotype was associated with resistance to the therapy (P=0.029). After adjusting for potential confounding variables, patients exhibiting the C/C genotype were less likely to respond to treatment than patients with the T/T or T/C genotypes. Conclusions: These results suggest that inheritance of the interleukin-10 −1082 G/G and the transforming growth factor-β1 +29 C/C genotypes, which appear to affect the cytokine production, may be associated with susceptibility to chronic hepatitis C infection and resistance to combined antiviral therapy.