title: [Antibodies to cyclic citrullinized peptide in rheumatoid arthritis].
abstract: OBJECTIVE
  To estimate a diagnostic value of antibodies to cyclic citrullinized peptide (CCP) in rheumatoid arthritis (RA).
  
  
  METHODS
  The study was made of 85 RA patients. Of them, 48 patients had early RA, i.e. of 8 month and less duration. The control group consisted of 35 patients with non-differentiated arthritis (NDA) and 8 healthy donors. Concentrations of CCP antibodies, rheumatoid factor (RF) IgM and RF IgA were measured with enzyme immunoassay (EIA).
  
  
  RESULTS
  The level of CCP antibodies in RA patients (76.3 +/- 43.8; median 100.0 U/ml) was significantly higher than in NDA patients (25.1 +/- 43.9; median 0.8 U/ml; p < 0.05) or in donors (0.38 +/- 0.36; median 0.2 U/ml; p < 0.05). A correlation was found between the CCP antibodies level and that of RF IgM (chi2 = 15.4; p = 0.001) and RF IgA (chi2 = 10.3; p = 0.001). Sensitivity (82%) and specificity (90%) of CCP antibodies in RA diagnosis was higher than these parameters for RF IgM and IgA (78%, 86% and 72%, 83%, respectively). Simultaneous tests for CCP antibodies, RF IgM and RF IgA led to a 93% specificity. CCP antibodies were detected in 50% patients seronegative by RF IgM and in 62% patients seronegative by IgA. Detection of CCP antibodies was closely associated with early RA (chi2 = 30.8; p = 0.0001).
  
  
  CONCLUSIONS
  The EIA for CCP antibodies is a sensitive and specific serological test for early RA diagnosis.
authors.forename: E N
authors.initials: EN
authors.lastname: Aleksandrova
authors.forename: N A
authors.initials: NA
authors.lastname: Chemeris
authors.forename: D E
authors.initials: DE
authors.lastname: Karateev
authors.forename: A A
authors.initials: AA
authors.lastname: Novikov
authors.forename: K A
authors.initials: KA
authors.lastname: Brodetskaia
authors.forename: E L
authors.initials: EL
authors.lastname: Nasonov
mesh_terms: D000328:Adult; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000175:diagnosis; D001323:Autoantibodies / Q000097:blood*; D016022:Case-Control Studies; D002956:Citrulline; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
chemical_list: D001323:Autoantibodies; D010456:Peptides, Cyclic; D002956:Citrulline