A recent study suggests that P. gingivalis induces autoimmune experimental arthritis via a mechanism that is independent of citrullination (e.g., induction of a Th17 response via toll-like receptor-2 and interleukin-1 signaling) [3]; thus further research is needed to clarify the arthritogenic role of P. gingivalis. The gene discussed is TLR2; the disease is arthritic joint disease.