Is periodontitis linked to low grade inflammation and development of rheumatoid arthritis?

Periodontitis (PD) is a dysbiosis-triggered chronic inflammation affecting the tooth-supporting tissue. Growing evidence indicates that there is an association between periodontitis and rheumatoid arthritis (RA). RA is an autoimmune disease characterised by a chronic inflammation of synovial membrane and joint destruction with an unclear aetiology. The association between PD and RA can be explained by, amongst others, shared risk factors like genetic predisposition and smoking, a high local and systemic inflammatory burden and induction of autoimmunity by chronic inflammation. Anti-citrullinated proteins antibodies (ACPA) and rheumatoid factor (RF) are hallmarks of seropositive RA. The presence of ACPA and RF have been reported to emerge in serum years before clinically diagnosed RA indicating the role of an extra-articular site as an inducing site. The aim of this study was to explore presumed links between PD and RA with emphasis on gingival crevicular fluid (GCF) and microbiome. The results showed: (1) RA patients have increased circulating and GCF levels of pro‐inflammatory cytokines and proteins, despite anti‐rheumatic treatment with biological DMARDs. The presence of PD was accompanied by higher cytokine and protein levels, (2) IgA‐ACPA present in GCF of healthy patients was associated with periodontal inflammation and smoking, and could be involved in the progression to RA, (3) no association exist between antibodies against P gingivalis, A actinomycetemcomitans and RA-specific autoantibodies, and (4) PD and certain taxa, including Porphyromonas, seem to be associated with local presence of ACPA in the periodontium