title: [The specificity of anti-cyclic citrullinated peptide antibodies in the diagnosis of rheumatoid arthritis from a large cohort study in the Chinese].
abstract: OBJECTIVE
  To determine the sensitivity and specificity of anti-cyclic citrullinated peptide antibodies (anti-CCP antibodies) in the diagnosis of rheumatoid arthritis.
  
  
  METHODS
  A total of 1018 healthy donors, 212 patients with rheumatoid arthritis, 435 patients with other connective tissue disease were recruited to this study. Anti-CCP antibodies and IgM-rheumatoid factor (RF) were determined by ELISA according to manufacturer instructions, with a cut-off of 20U.
  
  
  RESULTS
  The frequency of positive anti-CCP antibodies in patients with rheumatoid arthritis is 48.1% (n = 102), higher than healthy donors (2.6%, n = 26) and patients with other connective tissue diseases (3.7%, n = 16). The specificity of anti-CCP antibodies is 97.4%. The titer of anti-CCP antibodies in patients with rheumatoid arthritis (429.7 U) is much higher than that in healthy donors (29.3 U) and patients with other connective tissue diseases (36.5 U). The frequency of positive IgM-RF in patients with rheumatoid arthritis is 94.3% whilst only 21.5% in healthy donors. The false positivity rate of IgM-RF is higher than anti-CCP antibody.
  
  
  CONCLUSIONS
  Anti-CCP antibodies is a highly specific autoantibody in the diagnosis of rheumatoid arthritis.
authors.affiliation: Department of Rheumatology and Immunology, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Bao
authors.forename: Jian
authors.initials: J
authors.lastname: Yin
authors.forename: Hu-Ji
authors.initials: HJ
authors.lastname: Xu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000906:Antibodies / Q000097:blood* / Q000276:immunology; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D016022:Case-Control Studies; D003240:Connective Tissue Diseases / Q000097:blood / Q000276:immunology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000276:immunology*; D012217:Rheumatoid Factor / Q000097:blood / Q000276:immunology; D012680:Sensitivity and Specificity
chemical_list: D000906:Antibodies; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D012217:Rheumatoid Factor