title: Diagnostic value of anti-cyclic citrullinated Peptide antibody in patients with rheumatoid arthritis.
abstract: OBJECTIVE
  To explore the diagnostic value of anti-cyclic citrullinated peptide antibody (anti-CCP) detected by ELISA in patients with rheumatoid arthritis (RA).
  
  
  METHODS
  The synthesized cyclic citrullinated peptide was used as substrate for ELISA. Anti-CCP antibody was detected by ELISA in 191 patients with RA, 132 with rheumatic diseases other than RA, and 98 with nonrheumatic diseases. The antiperinuclear factor (APF), anti-keratin antibody (AKA), rheumatoid factor (RF), and HLA-DR4 gene complex were also tested in each RA patient. The results of these tests were compared with anti-CCP antibody to examine the correlation between them.
  
  
  RESULTS
  Ninety (47.1%) patients with RA, 4 (3.0%) with other rheumatic diseases, and 2 (2.0%) with nonrheumatic diseases were found to be anti-CCP antibody positive by ELISA. The sensitivity of anti-CCP antibody was 47.1%, with a high specificity (97.4%) in RA. Anti-CCP antibody correlated with APF, AKA, RF, and HLA-DR4 gene complex.
  
  
  CONCLUSIONS
  A new modified anti-CCP antibody test had a moderate sensitivity (47.1%) but a high specificity (97.4%) in patients with RA and was found as a valuable supplement to diagnosis of RA. Anti-CCP correlated with APF, AKA, RF, and HLA-DR4 gene complex, but did not completely overlap with them. Anti-CCP antibody could be regarded as a new diagnostic marker for RA.
authors.affiliation: Department of Rheumatology, Chinese Academy of Medical Science, Peking Union Medical College Hospital, Beijing, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Zeng
authors.forename: Maixing
authors.initials: M
authors.lastname: Ai
authors.forename: Xinping
authors.initials: X
authors.lastname: Tian
authors.forename: Xiaodan
authors.initials: X
authors.lastname: Gan
authors.forename: Yanping
authors.initials: Y
authors.lastname: Shi
authors.forename: Qinfang
authors.initials: Q
authors.lastname: Song
authors.forename: Fulin
authors.initials: F
authors.lastname: Tang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000974:Antibodies, Antinuclear / Q000097:blood; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D001323:Autoantibodies / Q000097:blood*; D002956:Citrulline / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015804:HLA-DR4 Antigen / Q000097:blood; D006801:Humans; D007633:Keratins / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000276:immunology*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012217:Rheumatoid Factor / Q000097:blood
chemical_list: D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D015804:HLA-DR4 Antigen; D010456:Peptides, Cyclic; C030902:antiperinuclear factor; D002956:Citrulline; D007633:Keratins; D012217:Rheumatoid Factor