title: Hepatitis C virus-related resistance mechanisms to interferon alpha-based antiviral therapy.
abstract: Only 50-60% of the patients chronically infected with the hepatitis C virus (HCV) achieve a sustained virologic response to the current standard antiviral therapy consisting of pegylated interferon alpha in combination with ribavirin. The definite reasons for virologic response or non-response to interferon alpha-based therapy are unknown. Besides host and treatment efficacy factors, it is presumable that HCV is able to antagonize the antiviral activity of interferon alpha. So far, among the different HCV proteins, the envelope (E)2 protein, the non-structural (NS)3/4A protein, and the NS5A protein have been associated with interferon alpha resistance mechanisms in vitro. The clinical significance of amino acid mutations within these HCV proteins in HCV isolates from patients who did or did not respond to interferon alpha-based therapy was investigated in multiple studies. Within the E2 (HVR2, CD81 binding sites, PePHD) and the NS3/4A proteins no specific mutations in correlation with virologic response to interferon alpha-based therapy were observed. For the NS5A protein, mutations within the interferon sensitivity determining region (ISDR) and the complete NS5A protein may be of importance for response to interferon alpha-based treatment in patients infected with HCV subtype 1a/b.
authors.affiliation: Universitätsklinikum des Saarlandes, Klinik für Innere Medizin II, Homburg/Saar, Germany.
authors.forename: Wolf Peter
authors.initials: WP
authors.lastname: Hofmann
authors.forename: Stefan
authors.initials: S
authors.lastname: Zeuzem
authors.forename: Christoph
authors.initials: C
authors.lastname: Sarrazin
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology* / Q000627:therapeutic use; D024882:Drug Resistance, Viral / Q000235:genetics; D004359:Drug Therapy, Combination; D016174:Hepacivirus / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology* / Q000627:therapeutic use; D009154:Mutation; D012254:Ribavirin / Q000494:pharmacology* / Q000627:therapeutic use; D014759:Viral Envelope Proteins / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000235:genetics
chemical_list: D000998:Antiviral Agents; D016898:Interferon-alpha; D014759:Viral Envelope Proteins; D017361:Viral Nonstructural Proteins; C091015:glycoprotein E2, Hepatitis C virus; D012254:Ribavirin