title: Influence of periodontal disease, Porphyromonas gingivalis and cigarette smoking on systemic anti-citrullinated peptide antibody titres.
abstract: BACKGROUND
  Anti-citrullinated protein antibody (ACPA) responses may precede clinical onset of rheumatoid arthritis. Porphyromonas gingivalis peptidylarginine deiminase can citrullinate proteins possibly inducing autoimmunity in susceptible individuals.
  
  
  OBJECTIVE
  To determine whether periodontitis, carriage of P. gingivalis, smoking and periodontal therapy influence ACPA titres.
  
  
  METHODS
  Serum and plaque samples were collected from 39 periodontitis patients before and after non-surgical periodontal treatment, and from 36 healthy subjects. Carriage of P. gingivalis was determined by PCR of plaque DNA. ACPA was determined by anti-cyclic citrullinated peptide (CCP) enzyme-linked immunosorbent assay (ELISA). Anti-P. gingivalis titres were determined by ELISA.
  
  
  RESULTS
  Untreated periodontitis patients had higher anti-CCP antibody titres than healthy controls [three patients (8%) greater than manufacturer suggested assay diagnostic threshold (5 Assay Units/AU) versus none (0%); mean ± SEM: 1.37 ± 0.23 versus 0.40 ± 0.10 AU, p < 0.0001]. Periodontitis patients who smoked demonstrated lower anti-P. gingivalis (15956 ± 4385 versus 2512 ± 1290 Units/ml, p < 0.05), but similar anti-CCP than non-smoking periodontitis patients (smokers: 1.31 ± 0.35; non-smokers: 1.41 ± 0.32 AU). Healthy smokers demonstrated elevated anti-CCP titres (0.75 ± 0.19 AU), at levels between healthy non-smokers (0.15 ± 0.05 AU) and non-smoker periodontitis patients. Six months after periodontal treatment, there were significant reductions in anti-CCP (non-smokers p < 0.05) and anti-P. gingivalis (all participants p < 0.01).
  
  
  CONCLUSIONS
  In subjects with periodontitis, P. gingivalis infection may be responsible for inducing autoimmune responses that characterize rheumatoid arthritis.
authors.affiliation: Infection and Immunity, University of Glasgow Dental School, School of Medicine, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, UK.
authors.forename: David F
authors.initials: DF
authors.lastname: Lappin
authors.forename: Danae
authors.initials: D
authors.lastname: Apatzidou
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Quirke
authors.forename: Jessica
authors.initials: J
authors.lastname: Oliver-Bell
authors.forename: John P
authors.initials: JP
authors.lastname: Butcher
authors.forename: Denis F
authors.initials: DF
authors.lastname: Kinane
authors.forename: Marcello P
authors.initials: MP
authors.lastname: Riggio
authors.forename: Patrick
authors.initials: P
authors.lastname: Venables
authors.forename: Iain B
authors.initials: IB
authors.lastname: McInnes
authors.forename: Shauna
authors.initials: S
authors.lastname: Culshaw
mesh_terms: D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000032:analysis / Q000097:blood; D015551:Autoimmunity / Q000276:immunology; D016022:Case-Control Studies; D055113:Chronic Periodontitis / Q000276:immunology* / Q000628:therapy; D003430:Cross-Sectional Studies; D004269:DNA, Bacterial / Q000032:analysis; D003773:Dental Plaque / Q000276:immunology / Q000382:microbiology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005884:Gingival Hemorrhage / Q000276:immunology / Q000628:therapy; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis / Q000097:blood; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000032:analysis* / Q000097:blood; D017622:Periodontal Attachment Loss / Q000276:immunology / Q000628:therapy; D057747:Periodontal Debridement / Q000379:methods; D010514:Periodontal Pocket / Q000276:immunology / Q000628:therapy; D010751:Phosphopyruvate Hydratase / Q000032:analysis / Q000097:blood; D016966:Porphyromonas gingivalis / Q000276:immunology*; D012907:Smoking / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D004269:DNA, Bacterial; D007074:Immunoglobulin G; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D010751:Phosphopyruvate Hydratase
keywords: autoimmunity; periodontal disease