Viral genotype correlates with distinct liver gene transcription signatures in chronic hepatitis C virus infection

Background: Chronic hepatitis C virus (HCV) infection of the liver with either genotype 1 or genotype 3 gives rise to distinct pathologies, and the two viral genotypes respond differently to antiviral therapy. Methods: To understand these clinical differences, we compared gene transcription profiles in liver biopsies from patients infected with either gt1 or gt3, and uninfected controls. Results: Gt1-infected biopsies displayed elevated levels of transcripts regulated by type I and type III interferons (IFN), including genes that predict response to IFN-a therapy. In contrast, genes controlled by IFN-c were induced in gt3-infected biopsies. Moreover, IFN-c levels were higher in gt3-infected biopsies. Analysis of hepatocyte-derived cell lines confirmed that the genes upregulated in gt3 infection were preferentially induced by IFN-c. The transcriptional profile of gt3 infection was unaffected by IFNL4 polymorphisms, providing a rationale for the reduced predictive power of IFNL genotyping in gt3-infected patients. Conclusions: The interactions between HCV genotypes 1 and 3 and hepatocytes are distinct. These unique interactions provide avenues to explore the biological mechanisms that drive viral genotype-specific differences in disease progression and treatment response. A greater understanding of the distinct host–pathogen interactions of the different HCV genotypes is required to facilitate optimal management of HCV infection