Background/Purpose:

Periodontal disease (PD) is associated mainly with rheumatoid arthritis (RA), but recent data suggest an association with ankylosing spondylitis (AS). Role of Porphyromonas gingivalis (P. gingivalis) in RA disease is growing fast since it is the only bacteria able to citrullinate peptides and may induce autoimmune response through development of ACPA. However, few studies have reported its presence in others inflammatory diseases. The aim of this study was to evaluate immunization against two oral pathogens: P. gingivalis and Prevotella intermedia (P. intermedia) in patients with RA, AS, inflammatory bowel disease (IBD), and healthy subjects.

Methods:

Seventy-nine RA patients, 56 AS patients, and 39 IBD patients requiring infliximab therapy enrolled in these study as well as 30 healthy controls. Anti-P. intermedia antibodies and anti-P. gingivalis LPS specific and whole extract antibodies were determined by specific ELISA. Specificity of these antibodies was evaluated by the measure of antibodies against the Escherichia Coli (E. coli) commensal bacterium of the intestinal tract.

Results:

Anti-P. gingivalis antibody titers directed against  LPS and/or whole extract were correlated together (P<0.0001) as well as antibody titers against the two oral bacteria (P. gingivalis and P. intermedia) (P<0.0001). By using LPS from E. coli, no cross reaction was observed between these two species.

Anti-P. gingivalis antibodies titers were higher in RA and AS patients than in healthy subjects (P< 0.0001) or in IBD patients (P< 0.0001). Moreover, there was a tendency for higher titers in RA patients than in SA patients (Fig 1A). Same results were found with anti-P. intermedia antibody titers which were higher in RA and AS patients than in healthy controls (P< 0.0001) or IBD patients (P< 0.0001) (Fig 1B).

Fig 1: Evaluation of anti-P. gingivalis (A) and anti-P. intermedia (B) antibodies in RA, AS, and IBD patients and in healthy controls.

*P < 0.0001

Conclusion:

Immunity against P. gingivalis and P. intermedia oral bacteria seems to have an important role in RA, but also in AS compared to other inflammatory disease as IBD.