TNFSF11 and rheumatoid arthritis: Markedly, P. gingivalis is the most elucidated in the development of RA, and studies using animal models have demonstrated the potential of this proinflammatory bacterium promoting the development of experimental arthritis and increased serum levels of C-reactive protein, TNF-α, IL-1β, IL-17, MMP-13, and RANKL [75].