Background Rheumatoid arthritis (RA) is characterized by antibodies to citrullinated protein antigens (ACPA). Porphyromonas gingivalis (PG) is a major pathogen in periodontitis which possesses a citrullinated enzyme, peptidylarginine deiminase with the potential to generate antigens leading the autoimmune response.
Objectives The aim of the study was to examine the existence of antibodies to PG in patients with RA.
Methods Antibodies to PG were measured using ELISA as previously described.1 Thus, Dynatech Immunolon IB microtitre plates (ThermoFisher) were coated overnight with PG strain W83 fixed in formalin cells. Correlations between PG antibody values and clinical parameters were performed using IBM SPSS statistics 20 Non-parametric Mann Whitney U test and Spearman correlation test were used for statistical analysis.
Results Thirty-six RA patients (10 men and 26 women) were studied. Sera from individuals with periodontitis and healthy subjects were used as controls. The mean age and disease duration of RA patients were 66.76±13.66 years and 20.06±11.01 years respectively. All the RA patients had ACPA while 30/36 (83.3%) had positive rheumatoid factor (RF). The mean DAS28 score was 4.58±1.37 and the mean HAQ score was 0.7±0.64. Twenty five out of 36 (69.4%) had anti-PG antibodies. There was no statistical difference between RA patients with and without anti-PG concerning DAS28 and HAQ scores. Thirteen out of 25 RA patients with anti-PG had lung involvement, 11/25 had sicca syndrome, 9/25 had rheumatoid nodules, 3/25 had Raynaud's and 4/25 had peripheral neuropathy. Patients with anti-PG had statistically more lung involvement (p<0.009) and more sicca syndrome (p<0.039). All the individuals with active periodontitis had positive anti-PG antibodies and negative ACPA and negative RF.
Conclusions RA patients with anti-PG had more frequently extraarticular manifestations especially lung involvement and sicca syndrome. The immune response to PG supports the hypothesis that a bacterial infection might contribute to the broken tolerance in RA.
Lappin DF, Apatzidou D, Quirke AM, Oliver-Bell J, Butcher JP, Kinane DF, Riggio MP, Venables P, McInnes IB, Culshaw S. Influence of periodontal disease, Porphyromonas gingivalis and cigarette smoking on systemic anti-citrullinated peptide antibody titres. J Clin Periodontol. 2013 Oct;40(10):907-15.
Disclosure of Interest None declared