Virulence Factors of Porphyromonas gingivalis in Periodontitis and Rheumatoid Arthritis: Clinical Implications

Porphyromonas gingivalis (P. gingivalis), has been implicated in exacerbating inflammatory arthritis through its virulence factors. Understanding the role of these factors could inform strategies to mitigate both periodontal and synovial inflammation. This study aimed to investigate the prevalence of P. gingivalis virulence factors and their potential impact on disease activity in patients with periodontitis, rheumatoid arthritis (RA), or both conditions. Patients with RA (n = 22), RA plus periodontitis (n = 22), periodontitis (n = 10), and healthy controls (n = 35), were compared for C-reactive protein levels, anti-cyclic citrullinated peptide IgG, peptidylarginine-deiminase (PAD)2/4 activity and anti-P. gingivalis virulence-associated gingipain antibodies. All patients with periodontitis were compared for P. gingivalis, Tannerella forsythia and Prevotella intermedia colony-forming units, and gene variants of P. gingivalis, including PAD (P.PAD), major fimbriae (fimA), lysine-gingipain (kgp), and receptor antigen gene B (ragB). Higher mean clinical periodontal attachment loss was observed with P.PAD type 1 (p = 0.033). The major fimbriae and lysine-gingipain gene variants showed distinct distributions between groups. Anti-gingipain IgG levels showed positive correlations with RA disease activity. Despite limitations, this study supports a role for P. gingivalis in exacerbating periodontitis and RA underscoring the importance of P. gingivalis virulence factors in disease modulation and highlighting potential therapeutic strategies. Further research is needed to elucidate mechanistic pathways and develop effective interventions. Trial Registration: ISRCTN 17950307; https://doi.org/10.1186/ISRCTN17950307.