title: Antibodies to mutated citrullinated vimentin and disease activity score in early arthritis: a cohort study.
abstract: BACKGROUND
  The aim of our study was to investigate the association between arthritic disease activity and antibodies to mutated citrullinated vimentin (anti-MCV), because such a relation has been suggested.
  
  
  METHODS
  Anti-MCV levels were measured in 162 patients with early arthritis (123 with rheumatoid arthritis and 39 with undifferentiated arthritis) at baseline and at 1 and 2 years of follow up. Disease activity was measured using the disease activity score (Disease Activity Score based on 28 joints [DAS28]) and serum C-reactive protein. General estimation equation analysis was used to assess the relation between anti-MCV levels and DAS28 over time.
  
  
  RESULTS
  Both, anti-MCV levels and DAS28 exhibited a significant decrease during the first and second year. However, the association between anti-MCV levels and DAS28, adjusted for dependency on sequential measurements within one individual, was very low (beta = 0.00075). In a population of patients with rheumatoid arthritis or undifferentiated arthritis, anti-MCV had a specificity of 92.3% and a sensitivity of 59.3% when using the recommended cut-off of 20 U/ml. Specificity and sensitivity of antibodies against second-generation cyclic citrullinated peptide, using the recommended cut-off value of 25 U/ml, were 92.1% and 55.3%, respectively. Anti-MCV-positive early arthritis patients had significantly higher Sharp-van der Heijde score, erythrocyte sedimentation rate and C-reactive protein levels than did anti-MCV-negative patients at all time points (P < 0.005), but DAS28 was higher in anti-MCV-positive patients at 2 years of follow up only (P < 0.05).
  
  
  CONCLUSIONS
  Because the correlation between anti-MCV levels and parameters of disease activity was very low, we conclude that it is not useful to monitor disease activity with anti-MCV levels.
authors.affiliation: Jan van Breemen Institute, Dr Jan van Breemenstraat, 1056 AB Amsterdam, The Netherlands. j.ursum@janvanbreemen.nl
authors.forename: Jennie
authors.initials: J
authors.lastname: Ursum
authors.forename: Markus M J
authors.initials: MM
authors.lastname: Nielen
authors.forename: Dirkjan
authors.initials: D
authors.lastname: van Schaardenburg
authors.forename: Ann R
authors.initials: AR
authors.lastname: van der Horst
authors.forename: Rob J
authors.initials: RJ
authors.lastname: van de Stadt
authors.forename: Ben A C
authors.initials: BA
authors.lastname: Dijkmans
authors.forename: Dörte
authors.initials: D
authors.lastname: Hamann
mesh_terms: D000328:Adult; D000906:Antibodies / Q000097:blood*; D001168:Arthritis / Q000000981:diagnostic imaging* / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology*; D002956:Citrulline / Q000378:metabolism*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D009154:Mutation; D010456:Peptides, Cyclic / Q000276:immunology; D011859:Radiography; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D014746:Vimentin / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*
chemical_list: D000906:Antibodies; D010456:Peptides, Cyclic; D014746:Vimentin; C487763:cyclic citrullinated peptide; D002956:Citrulline