title: Anti-carbamylated protein (anti-CarP) antibodies precede the onset of rheumatoid arthritis.
abstract: OBJECTIVE
  The presence of anti-citrullinated protein antibodies (ACPA) and IgM-rheumatoid factor (IgM-RF) years before the clinical diagnosis of rheumatoid arthritis (RA) suggests they are possibly involved in the pathogenic process underlying RA. In this study, we analysed whether anti-carbamylated protein (anti-CarP) antibodies, a novel autoantibody system against carbamylated proteins, can also be detected in healthy individuals before they developed RA.
  
  
  METHODS
  Multiple sera from asymptomatic blood donors prior to the onset of their RA symptoms and sera from age-matched and sex-matched controls were tested for the presence of antibodies directed against carbamylated-fetal calf serum (Ca-FCS), carbamylated-fibrinogen (Ca-Fib), cyclic citrullinated-peptide 2 and IgM-RF.
  
  
  RESULTS
  Anti-Ca-FCS and anti-Ca-Fib antibodies were each present in 27% and 38% of the last serum samples of blood donors prior to the diagnosis of RA. Both anti-Ca-FCS and anti-Ca-Fib antibodies could be detected many years before the onset of RA. Anti-CarP antibodies as well as ACPA are, on average, detected earlier than IgM-RF.
  
  
  CONCLUSIONS
  In addition to ACPA and IgM-RF, also the newly identified anti-CarP antibodies appear many years before the diagnosis of RA.
authors: Department of Rheumatology, Leiden University Medical Center, , Leiden, The Netherlands.
authors: Jing
authors: J
authors: Shi
authors: Lotte A
authors: LA
authors: van de Stadt
authors: E W Nivine
authors: EW
authors: Levarht
authors: Tom W J
authors: TW
authors: Huizinga
authors: Dörte
authors: D
authors: Hamann
authors: Dirkjan
authors: D
authors: van Schaardenburg
authors: René E M
authors: RE
authors: Toes
authors: Leendert A
authors: LA
authors: Trouw
mesh_terms: D001172:Arthritis, Rheumatoid / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood*; D001324:Autoantigens / Q000276:immunology; D001798:Blood Proteins / Q000276:immunology*; D002219:Carbamates / Q000276:immunology*; D016022:Case-Control Studies; D005260:Female; D005340:Fibrinogen / Q000276:immunology; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000276:immunology; D062706:Prodromal Symptoms; D012217:Rheumatoid Factor / Q000097:blood; D013997:Time Factors
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D001798:Blood Proteins; D002219:Carbamates; D007075:Immunoglobulin M; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D005340:Fibrinogen; D012217:Rheumatoid Factor
keywords: Ant-CCP; Autoantibodies; Early Rheumatoid Arthritis; Rheumatoid Factor