title: Focal distribution of hepatitis C virus RNA in infected livers.
abstract: BACKGROUND
  Hepatitis C virus (HCV) is a plus-strand RNA virus that replicates by amplification of genomic RNA from minus strands leading to accumulation of almost one thousand copies per cell under in vitro cell culture conditions. In contrast, HCV RNA copy numbers in livers of infected patients appear to be much lower, estimated at a few copies per cell.
  
  
  RESULTS
  To gain insights into mechanisms that control HCV replication in vivo, we analyzed HCV RNA levels as well as expression of interferon beta (IFNbeta) and several interferon stimulated genes (ISGs) from whole liver sections and micro-dissected subpopulations of hepatocytes in biopsy samples from 21 HCV-infected patients. The results showed that intrahepatic HCV RNA levels range form less than one copy per hepatocyte to a maximum of about eight. A correlation existed between viral RNA levels and IFNbeta expression, but not between viral RNA and ISG levels. Also, IFNbeta expression did not correlate with ISGs levels. Replication of HCV RNA occurred in focal areas in the liver in the presence of a general induction of ISGs.
  
  
  CONCLUSIONS
  The low average levels of HCV RNA in biopsy samples can be explained by focal distribution of infected hepatocytes. HCV replication directly induces IFNbeta, which then activates ISGs. The apparent lack of a correlation between levels of IFNbeta and ISG expression indicates that control of the innate immune response during HCV infections depends on multiple factors.
authors.affiliation: Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
authors.forename: J David
authors.initials: JD
authors.lastname: Stiffler
authors.forename: Minhhuyen
authors.initials: M
authors.lastname: Nguyen
authors.forename: Ji A
authors.initials: JA
authors.lastname: Sohn
authors.forename: Chen
authors.initials: C
authors.lastname: Liu
authors.forename: David
authors.initials: D
authors.lastname: Kaplan
authors.forename: Christoph
authors.initials: C
authors.lastname: Seeger
mesh_terms: D015153:Blotting, Western; D015331:Cohort Studies; D018628:Gene Dosage; D016174:Hepacivirus / Q000235:genetics*; D006526:Hepatitis C / Q000188:drug therapy / Q000821:virology; D006801:Humans; D007372:Interferons / Q000627:therapeutic use; D008099:Liver / Q000378:metabolism* / Q000821:virology; D012367:RNA, Viral / Q000378:metabolism*
chemical_list: D012367:RNA, Viral; D007372:Interferons
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