title: Clinical utility of total HCV core antigen quantification: a new indirect marker of HCV replication.
abstract: Hepatitis C virus (HCV) RNA detection, viral load quantification, and HCV genotyping are widely used in clinical practice. Recently, the availability of an anticore antigen (Ag) monoclonal antibody allowed development of an enzyme-linked immunosorbent assay (ELISA) detecting and quantifying total HCV core Ag in peripheral blood of HCV-infected patients. The aims of the present study were to investigate the biologic significance of this new marker in HCV infection, to establish the intrinsic performance of the current assay, and to determine its potential utility in the management of HCV-infected patients. A panel of infected sera calibrated to the World Health Organization International Standard and 657 serum samples from infected patients receiving antiviral treatment were studied. We showed that total HCV core Ag quantification is an accurate, precise, and specific indirect marker of HCV replication. We estimated that 1 pg/mL of total HCV core Ag is equivalent to approximately 8,000 HCV RNA international units (IU)/mL, although minor between-patient differences may exist. In conclusion, total HCV core Ag quantification can be used in the various indications of viral load monitoring, including the evaluation of baseline viral load before therapy, the assessment of the virologic response to antiviral treatment, and the study of early viral kinetics during therapy. Nevertheless, the total HCV core Ag assay cannot be used as a marker of viral replication for HCV RNA values below 20,000 IU/mL, limiting its use in the monitoring of late events during and after antiviral treatment.
authors.affiliation: Department of Virology (EA 3489), Hôpital Henri Mondor, Université Paris XII, 51 avenue du Maréchal de Lattre de Tassigny, 94010 Créteil, France.
authors.forename: Magali
authors.initials: M
authors.lastname: Bouvier-Alias
authors.forename: Keyur
authors.initials: K
authors.lastname: Patel
authors.forename: Harel
authors.initials: H
authors.lastname: Dahari
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Beaucourt
authors.forename: Patrick
authors.initials: P
authors.lastname: Larderie
authors.forename: Lawrence
authors.initials: L
authors.lastname: Blatt
authors.forename: Christophe
authors.initials: C
authors.lastname: Hezode
authors.forename: Gaston
authors.initials: G
authors.lastname: Picchio
authors.forename: Daniel
authors.initials: D
authors.lastname: Dhumeaux
authors.forename: Avidan U
authors.initials: AU
authors.lastname: Neumann
authors.forename: John G
authors.initials: JG
authors.lastname: McHutchison
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Pawlotsky
mesh_terms: D015415:Biomarkers / Q000097:blood*; D005838:Genotype; D016174:Hepacivirus / Q000235:genetics / Q000254:growth & development*; D006526:Hepatitis C / Q000628:therapy / Q000821:virology; D006801:Humans; D007700:Kinetics; D012367:RNA, Viral / Q000097:blood; D012680:Sensitivity and Specificity; D014758:Viral Core Proteins / Q000032:analysis* / Q000097:blood*; D014779:Virus Replication
chemical_list: D015415:Biomarkers; D012367:RNA, Viral; D014758:Viral Core Proteins; C069130:nucleocapsid protein, Hepatitis C virus