Anti-Porphyromonas gingivalis lipopolysaccharide antibody in rheumatoid arthritis patients with emphysema

Objective Lung diseases that are chronic (emphysema [EMP], airway disease, interstitial lung disease) can complicate rheumatoid arthritis (RA) as extra-articular manifestations. Anti- Porphyromonas gingivalis ( P. gingivalis ) antibody (Ab) has been analyzed for the diagnosis of periodontal disease and RA patients showed increased anti- P. gingivalis Ab levels. However, amounts of anti- P. gingivalis Ab in RA complicated with chronic lung disease (CLD) are unknown. We measured anti- P. gingivalis Ab in cases of RA with CLD. Methods Anti- P. gingivalis lipopolysaccharide (LPS) Ab were measured in RA patient sera by enzyme immunoassay. Results Anti- P. gingivalis LPS Ab levels in RA with EMP were significantly lower than in RA cases without CLD ( P = 0.0190, mean ± standard deviation [SD], 32.7 ± 64.2 [×10 3 U/mL] vs. 403.5 ± 2552.7 [×10 3 U/mL]). Multiple logistic regression analyses revealed the independence of this association. Anti- P. gingivalis LPS Ab amounts were increased in RA without CLD ( P = 0.0412) compared with healthy controls (77.6 ± 183.7 [×10 3 U/mL]). Conclusion Anti- P. gingivalis LPS Ab levels in RA with EMP were lower compared with RA without CLD. Citrullinated peptides were mainly generated in the lungs of RA with EMP and the oral cavity of RA without CLD, suggesting the heterogeneity of RA.