title: ACPA fine-specificity profiles in early rheumatoid arthritis patients do not correlate with clinical features at baseline or with disease progression.
abstract: BACKGROUND
  Autoantibodies against citrullinated peptides/proteins (ACPA) are found in approximately 75% of the sera of patients with rheumatoid arthritis (RA). The RA-specific ACPA are frequently present prior to disease onset and their presence associates with a more erosive disease course. ACPA can therefore be used to aid the diagnosis and prognosis of RA. Recently, it became clear that ACPA are very heterogeneous, both in an individual patient and among different patients. The aim of this study was to investigate whether clinically meaningful ACPA profiles exist in early RA patients.
  
  
  METHODS
  Twenty citrullinated peptides and the corresponding non-citrullinated control peptides were immobilized on microarray sensor chips. Sera from 374 early arthritis patients were analyzed by surface plasmon resonance imaging (iSPR) of biomolecular interactions on the sensor chip.
  
  
  RESULTS
  Cluster analysis of the reactivities with the citrullinated peptides, after subtraction of the reactivities with the corresponding control peptides confirmed the heterogeneity of the ACPA response in RA and revealed 12 distinct ACPA profiles. The association of the 5 most frequent profiles with clinical features at diagnosis and during the disease course was examined, showing no statistically significant associations.
  
  
  CONCLUSIONS
  Compared to the detection of ACPA in RA sera by CCP-based assays, ACPA profiling in early arthritis patients did not reveal associations with disease activity and progression scores.
authors.forename: Joyce J B C
authors.initials: JJ
authors.lastname: van Beers
authors.forename: Annemiek
authors.initials: A
authors.lastname: Willemze
authors.forename: Jeroen J
authors.initials: JJ
authors.lastname: Jansen
authors.forename: Gerard H M
authors.initials: GH
authors.lastname: Engbers
authors.forename: Martin
authors.initials: M
authors.lastname: Salden
authors.forename: Jos
authors.initials: J
authors.lastname: Raats
authors.forename: Jan W
authors.initials: JW
authors.lastname: Drijfhout
authors.forename: Annette H M
authors.initials: AH
authors.lastname: van der Helm-van Mil
authors.forename: Rene E M
authors.initials: RE
authors.lastname: Toes
authors.forename: Ger J M
authors.initials: GJ
authors.lastname: Pruijn
mesh_terms: D000595:Amino Acid Sequence; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000276:immunology* / Q000473:pathology; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D002956:Citrulline / Q000276:immunology; D018450:Disease Progression; D006801:Humans; D008969:Molecular Sequence Data; D010455:Peptides / Q000276:immunology*; D010456:Peptides, Cyclic / Q000276:immunology*; D025341:Principal Component Analysis; D020349:Surface Plasmon Resonance; D013997:Time Factors
chemical_list: D001323:Autoantibodies; D010455:Peptides; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D002956:Citrulline