title: The periodontium of periodontitis patients contains citrullinated proteins which may play a role in ACPA (anti-citrullinated protein antibody) formation.
abstract: OBJECTIVE
  To determine the presence and location (stroma versus epithelium) of citrullinated proteins in periodontitis tissue as compared to non-periodontitis tissue and synovial tissue of RA patients.
  
  
  METHODS
  Periodontitis, healthy periodontal and RA-affected synovial tissue samples were collected in addition to buccal swabs. These samples were stained for the presence of citrullinated proteins using polyclonal (Ab5612) and monoclonal (F95) antibodies. Furthermore, Western blotting with F95 was performed on lysates prepared from periodontal and synovial tissues.
  
  
  RESULTS
  In periodontitis stroma, increased citrullinated protein presence (80%) was observed compared with control stroma (33%), the latter was associated with inflammation of non-periodontitis origin. Periodontal epithelium always stained positive for Ab5612. Noteworthy, only periodontitis-affected epithelium stained positive for F95. All buccal mucosal swabs and 3 of 4 synovial tissue samples stained positive for both Ab5612 and F95. Western blotting with F95 showed presence of similar citrullinated proteins in both periodontitis and RA-affected synovial tissue.
  
  
  CONCLUSIONS
  Within the periodontal stroma, citrullination is an inflammation-depended process. In periodontal epithelium, citrullination is a physiological process. Additional citrullinated proteins are formed in periodontitis, apparently similar to those formed in RA-affected synovial tissue. Periodontitis induced citrullination may play a role in the aetiology of rheumatoid arthritis.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands. w.nesse@kchir.umcg.nl
authors.forename: Willem
authors.initials: W
authors.lastname: Nesse
authors.forename: Johanna
authors.initials: J
authors.lastname: Westra
authors.forename: Jacqueline E
authors.initials: JE
authors.lastname: van der Wal
authors.forename: Frank
authors.initials: F
authors.lastname: Abbas
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Nicholas
authors.forename: Arjan
authors.initials: A
authors.lastname: Vissink
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Brouwer
mesh_terms: D000911:Antibodies, Monoclonal; D001172:Arthritis, Rheumatoid / Q000276:immunology / Q000378:metabolism; D001323:Autoantibodies / Q000096:biosynthesis / Q000276:immunology*; D055113:Chronic Periodontitis / Q000276:immunology / Q000378:metabolism*; D002956:Citrulline / Q000032:analysis* / Q000276:immunology; D003238:Connective Tissue / Q000276:immunology / Q000378:metabolism; D004848:Epithelium / Q000276:immunology / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000276:immunology / Q000378:metabolism; D010519:Periodontium / Q000276:immunology / Q000378:metabolism*; D011506:Proteins / Q000032:analysis* / Q000276:immunology; D012907:Smoking; D013583:Synovial Membrane / Q000276:immunology / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D011506:Proteins; D002956:Citrulline