title: Anti-cyclic citrullinated peptides positivity rate in patients with familial Mediterranean fever.
abstract: OBJECTIVE
  To investigate the prevalence and levels of anti-cyclic citrullinated peptide antibodies (anti-CCP) in patients with familial Mediterranean fever (FMF) with and without arthritis.
  
  
  METHODS
  Eighty-three patients with FMF and 43 healthy controls were included in the study. Thirty seven FMF patients had a history of arthritis, and 46 patients did not. Serum antibodies directed to the anti-CCP were assessed with a commercial enzyme-linked immunosorbent assay (ELISA) kit. Values <20U were considered negative, between 20 and 39U low, 40-99U moderate, and >100U high positive.
  
  
  RESULTS
  Positivity rate of anti-CCP in the whole FMF group (14.5%) was three-fold higher than the control group (4.7%). However, the difference failed to achieve a statistically significant level (p=0.09). Anti-CCP levels were 21±30.1 in patients with arthritis and 13.1±10.3 in the non arthritic group (p<0.05). Anti-CCP positivity rates were 10/37 (27%) in patients with arthritis and 2/46 (4.3%) in patients without arthritis (p<0.005). Five FMF patients with arthritis (13.5%) had moderate-high anti-CCP levels (>40U/ml). Anti-CCP levels were between 20-39U/ ml in 2FMF patients without arthritis and in 2 healthy controls. Anti-CCP positivity rate is higher in FMF patients with arthritis (27%) than healthy controls (4.7%) (p<0.005).
  
  
  CONCLUSIONS
  Anti-CCP prevalence is higher in FMF patients with arthritis than without arthritis, and that a significant proportion of FMF patients with arthritis (13.5%) had moderate-high titers of anti-CCP. Therefore, anti-CCP antibodies may not be a reliable indicator to differentiate between FMF arthritis and rheumatoid arthritis.
authors.affiliation: Department of Nephrology, Ankara Education and Research Hospital, Ankara, Turkey. tscer@yahoo.com
authors.forename: Mevlut
authors.initials: M
authors.lastname: Ceri
authors.forename: Selman
authors.initials: S
authors.lastname: Unverdi
authors.forename: Mustafa
authors.initials: M
authors.lastname: Altay
authors.forename: Kemal
authors.initials: K
authors.lastname: Ureten
authors.forename: M Akif
authors.initials: MA
authors.lastname: Oztürk
authors.forename: Namik
authors.initials: N
authors.lastname: Gönen
authors.forename: Murat
authors.initials: M
authors.lastname: Duranay
mesh_terms: D000328:Adult; D000888:Antibodies, Anti-Idiotypic / Q000097:blood*; D001168:Arthritis / Q000097:blood / Q000175:diagnosis / Q000276:immunology; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D003937:Diagnosis, Differential; D010505:Familial Mediterranean Fever / Q000097:blood* / Q000175:diagnosis / Q000276:immunology; D005260:Female; D006801:Humans; D008297:Male; D010456:Peptides, Cyclic / Q000276:immunology*; D012680:Sensitivity and Specificity
chemical_list: D000888:Antibodies, Anti-Idiotypic; D015415:Biomarkers; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide