title: What is the ability of anti-cyclic citrullinated peptide antibodies determination in synovial fluid in discriminating rheumatoid arthritis from non-rheumatoid arthritis patients? A Tunisian cross-sectional study.
abstract: Anti-cyclic citrullinated peptide antibodies (ACPA) seem to be produced locally at the site of joints inflammation in the first stage of rheumatoid arthritis (RA). A strong correlation between serum ACPA and ACPA in the synovial fluid (SF-ACPA) is now suggested. A case-control study was conducted to evaluate the usefulness of ACPA determination in SF of patients with RA. A total of 53 patients with a knee-joint effusion (26 RA, 18 peripheral spondyloarthropathies (SPA), and 9 osteoarthritis (OA)) were included in our study. SF samples were obtained by performing therapeutic arthrosynthesis. IgG serum ACPA and SF-ACPA levels were determined by the enzyme-linked immunosorbent assay (ELISA). We have also determined IgG levels in serum and SF by nephelometry. Higher levels of IgG ACPA antibodies in SF (p = 0.045) and serum (p = 0.045) were found in patients with RA with respect to SPA and OA patients. The Spearman correlation analysis showed a significant and positive correlation between ACPA in serum and SF (rho = 0.516; p = 0.007) not only in the RA group but also in patients with SPA. Serum ACPA discriminated RA from non-RA at a cut-off value of 2.7 U/ml (sensitivity, 69%; specificity, 78%; and area under the curve (AUC), 0.72), whereas SF-ACPA discriminated RA from non-RA at a higher cut-off value of 4.95 U/ml (sensitivity, 73%; specificity, 61%; and AUC, 0.71). Our study suggests that the determination of SF-ACPA give complement information to serum ACPA in patients with RA.
authors.affiliation: Rheumatology Department, La Rabta Hospital, Tunis, 1007, Tunisia. mrabetdalila@yahoo.fr
authors.forename: Dalila
authors.initials: D
authors.lastname: Mrabet
authors.forename: Lilia
authors.initials: L
authors.lastname: Laadhar
authors.forename: Héla
authors.initials: H
authors.lastname: Sahli
authors.forename: Béchir
authors.initials: B
authors.lastname: Zouari
authors.forename: Slim
authors.initials: S
authors.lastname: Haouet
authors.forename: Houria
authors.initials: H
authors.lastname: Lahmar
authors.forename: Sondes
authors.initials: S
authors.lastname: Makni
authors.forename: Slaheddine
authors.initials: S
authors.lastname: Sellami
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D010456:Peptides, Cyclic / Q000097:blood / Q000276:immunology*; D013167:Spondylitis, Ankylosing / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D013582:Synovial Fluid / Q000276:immunology*; D014416:Tunisia
chemical_list: D001323:Autoantibodies; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide