title: Expression of anti-Porphyromonas gingivalis peptidylarginine deiminase immunoglobulin G and peptidylarginine deiminase-4 in patients with rheumatoid arthritis and periodontitis.
abstract: OBJECTIVE
  Autoimmunity against citrullinated proteins through peptidylarginine deiminase (PAD) may be involved in the pathophysiology of rheumatoid arthritis (RA). The present study evaluated the serum levels of antibodies to citrullinated proteins and to Porphyromonas gingivalis PAD (PPAD), and the endogenous expression of PAD-4, in individuals with and without RA, as well as before and after periodontal treatment.
  
  
  METHODS
  The study participants consisted of 52 patients with RA (RA group) and 26 age-, gender- and smoking status-matched healthy controls (non-RA group). Of the 52 patients, 26 were randomly assigned to receive oral hygiene instruction and supragingival scaling (RA subgroup). After periodontal and rheumatologic assessments, the serum levels of anti-cyclic citrullinated peptide (CCP) immunoglobulin G (IgG), anti-PPAD IgG and PAD-4 were determined using ELISA.
  
  
  RESULTS
  The serum levels of anti-CCP IgG and anti-PPAD IgG were significantly higher in the RA group than in the non-RA group (p < 0.001 and p = 0.03). A significant, positive correlation was observed between the serum levels of anti-PPAD IgG and anti-CCP IgG (p = 0.04), but not between the serum levels of PAD-4 and anti-CCP IgG. Multiple logistic regression analyses revealed a significant association between anti-PPAD IgG responses and RA after adjustment for age, gender and smoking (p = 0.004). Supragingival scaling significantly improved the periodontal condition and disease activity of RA (p < 0.05), but failed to decrease the serum levels of anti-CCP IgG, anti-PPAD IgG and PAD-4 after 2 mo of treatment.
  
  
  CONCLUSIONS
  These results might suggest an association between anti-PPAD IgG and anti-CCP IgG responses, implicating a role for PPAD in protein citrullination in patients with RA and periodontitis.
authors.affiliation: Division of Periodontology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Shimada
authors.affiliation: Division of Periodontology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.|General Dentistry and Clinical Education Unit, Niigata University Medical and Dental Hospital, Niigata, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: Niigata Rheumatic Center, Shibata, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ito
authors.affiliation: Division of Periodontology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Okada
authors.affiliation: Niigata Rheumatic Center, Shibata, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Murasawa
authors.affiliation: Niigata Rheumatic Center, Shibata, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Nakazono
authors.affiliation: Division of Periodontology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yoshie
mesh_terms: D001172:Arthritis, Rheumatoid; D001323:Autoantibodies; D006801:Humans; D007074:Immunoglobulin G; D010456:Peptides, Cyclic; D010518:Periodontitis; D016966:Porphyromonas gingivalis; D000080002:Protein-Arginine Deiminase Type 4; D000076342:Protein-Arginine Deiminases
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G; D010456:Peptides, Cyclic; C000629235:PADI4 protein, human; D000080002:Protein-Arginine Deiminase Type 4; D000076342:Protein-Arginine Deiminases
keywords: Porphyromonas gingivalis; peptidylarginine deiminase; periodontitis; rheumatoid arthritis