title: Absence of cyclic citrullinated peptide antibody in nonarthritic patients with chronic hepatitis C infection.
abstract: OBJECTIVE
  The increased prevalence of rheumatoid factor (RF) in patients with chronic hepatitis C virus (HCV) infection markedly diminishes the diagnostic specificity of serum rheumatoid factor (RF) for rheumatoid arthritis (RA) in patients with HCV. Cyclic citrullinated peptide (CCP) antibody, a highly specific biomarker for RA in the general population, may have better diagnostic utility for RA in the HCV population. To investigate if CCP antibody retains its specificity for RA in HCV infection, we determined the prevalence of CCP antibodies and examined the relationship between RF production and CCP antibody levels in a population of nonarthritic patients with chronic HCV infection.
  
  
  METHODS
  CCP antibody and IgM, IgG, and IgA RF isotypes were determined by ELISA in serum from nonarthritic patients with chronic HCV infection.
  
  
  RESULTS
  In a series of 50 HCV patients, IgG-RF, IgM-RF, and IgA-RF were detectable in 52%, 26%, and 14%, respectively, with a total seropositivity rate of 54%. Marginally elevated CCP antibody was detected in a single patient (2%). By regression analysis, serum levels of CCP antibodies did not correlate with RF levels.
  
  
  CONCLUSIONS
  In contrast to RF, CCP antibody is not increased in HCV infection. CCP antibody may have improved utility for the diagnosis of RA in this patient population.
authors.affiliation: Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA. lienesd@ucmail.uc.edu
authors.forename: Douglas
authors.initials: D
authors.lastname: Lienesch
authors.forename: Robert
authors.initials: R
authors.lastname: Morris
authors.forename: Allan
authors.initials: A
authors.lastname: Metzger
authors.forename: Paige
authors.initials: P
authors.lastname: Debuys
authors.forename: Kenneth
authors.initials: K
authors.lastname: Sherman
mesh_terms: D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis*; D001323:Autoantibodies / Q000097:blood; D015415:Biomarkers; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006526:Hepatitis C / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000097:blood*; D012217:Rheumatoid Factor / Q000097:blood; D012680:Sensitivity and Specificity; D013223:Statistics as Topic
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D012217:Rheumatoid Factor