"Rheumatoid arthritis (RA) is a complex autoimmune disease affecting 1-2% of general worldwide population. The etiopathogenesis of RA involves the interplay of multiple genetic risk factors and environmental triggers. Microbial infections are believed to play an important role in the initiation and perpetuation of Rheumatoid arthritis. Recent clinical studies have shown the association of microbial infections with RA. Accumulated studies using animal models have also found that microbial infections can induce and/or exaggerate the symptoms of experimental arthritis. In this review, we have identified the most common microbial infections associated with RA in the literature and summarized the current evidence supporting their pathogenic role in RA.
Numerous studies have shown the clinical association of microbial infection with RA. Infection is often detected in early Rheumatoid arthritis and can precede the occurrence of clinical arthritis. The pathogenic role of infection in RA is also suggested by studies using arthritis animal models. Among the Rheumatoid arthritis associated microbes, P. gingivalis shows the greatest promise as a significant contributor to RA etiology. P. gingivalis is the only known prokaryotic organism that contains enzyme peptidylarginine deiminase (PAD) which is essential for the generation of citrullinated autoantigens. Human studies have shown the association of P. gingivalis infection with RA patients and individuals at high risk for RA. Animal studies also demonstrated that P. gingivalis infection facilitated the development and progression of destructive arthritis. And more interestingly, this effect is dependent on P. gingivalis PAD. Future prospective studies examining P. gingivalis infection in patients before and at the early- onset of Rheumatoid arthritis using serial collections of patient sera are necessary to confirm the etiopathogenetic role of P. gingivalis in RA. Multivariate analyses stratified by Rheumatoid arthritis related factors such as susceptible gene alleles and smoking are also required to pinpoint the role of P. gingivalis infection in RA.
Last date updated on July, 2014