title: Diagnostic value of the anti-Sa antibody compared with the anti-cyclic citrullinated peptide antibody in rheumatoid arthritis.
abstract: OBJECTIVE
  To evaluate the prevalence and diagnostic significance of the autoantibody against citrullinated vimentin (anti-Sa) compared with the widely used anti-cyclic citrullinated peptide autoantibody (anti-CCP) in patients with rheumatoid arthritis (RA).
  
  
  METHODS
  One hundred and sixty-nine patients hospitalized at the Department of Rheumatology and Internal Medicine, Poznan University of Medical Sciences, Poznań, Poland, were enrolled in a cross-sectional study and divided into two groups. The RA group comprised 41 patients diagnosed as having RA. The non-RA control group included 128 individuals with a variety of rheumatic disorders. Serum anti-Sa and anti-CCP measurements were performed by enzyme-linked immunosorbent assay.
  
  
  RESULTS
  The sensitivity and specificity of anti-Sa for the diagnosis of RA was 36.6% and 96.9%, respectively. For the anti-CCP test, the sensitivity was 65.9% and the specificity was 95.3%. Concomitant presence of anti-Sa and anti-CCP was determined in 36.6% of the patients with RA, whereas isolated positivity of anti-Sa was not observed. Anti-Sa positive RA patients had significantly higher anti-CCP levels compared to anti-Sa negative subjects (P < 0.05).
  
  
  CONCLUSIONS
  With regard to the relatively low diagnostic sensitivity and the lack of cases identified by anti-Sa alone, we were unable to demonstrate any additional diagnostic value of the anti-Sa autoantibody in comparison to the anti-CCP autoantibody. To the authors' best knowledge, this is the first study among Polish patients verifying the clinical utility of anti-Sa in the diagnosis of RA.
authors.affiliation: Department of Rheumatology and Internal Medicine, Poznan University of Medical Sciences, Poznań, Poland.
authors.forename: Cezary
authors.initials: C
authors.lastname: Iwaszkiewicz
authors.forename: Mariusz
authors.initials: M
authors.lastname: Puszczewicz
authors.forename: Grażyna
authors.initials: G
authors.lastname: Białkowska-Puszczewicz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000974:Antibodies, Antinuclear / Q000097:blood*; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000276:immunology*; D011044:Poland; D011237:Predictive Value of Tests; D011379:Prognosis; D055815:Young Adult
chemical_list: D000974:Antibodies, Antinuclear; D015415:Biomarkers; D010456:Peptides, Cyclic; C035356:SS-A antibodies; C487763:cyclic citrullinated peptide
keywords: anti-CCP; anti-MCV; anti-Sa; citrullinated vimentin; rheumatoid arthritis