Oral microbiome influences the risk of developing rheumatoid arthritis

The relationship between autoimmune disease and microbes is a matter of debate for several decades. The recent discoveries of the role played by microbiomes in maintaining the integrity of the immune system and response.

A novel study conducted by a group of researchers from the Netherlands has found that individuals at risk of developing RA and those with early RA had increased occurrence of pro-inflammatory bacteria, namely Prevotella and Veillonella, in their saliva and the bacterial coating of their tongue. This finding suggests a possible association between oral microbiota and the onset of RA.

Comparison of the microbial composition across patients with early RA, at-risk individuals, and healthy controls showed significant differences in the microbial composition of saliva (F = 2.08, P = 0.0002) and tongue coating (F = 2.04, P = 0.008).

Several studies have shown that oral microbes, especially anaerobic bacteria, may influence the risk of developing RA. A 2009 study by Mesut Ogrendik has provided evidence on the direct association between oral bacteria and etiopathogenesis of RA.

The researchers have identified the following bacteria in the synovial fluid of RA patients: Porphyromonas gingivalis, Tannerella forsythensis, and Prevotella intermedia. The study also reported an increased incidence of periodontal disease in patients with long-standing RA.

Some studies focusing on the gut microbiome have also demonstrated an increased abundance of Prevotella species in subjects with early RA and at-risk individuals. Further studies focusing on the association of oral microbiome in the onset of RA may assist in developing potential targets in the prediction and prevention of RA.

Reference: Kroese JM, Brandt BW, Buijs MJ, et al. Differences in the Oral Microbiome in Patients With Early Rheumatoid Arthritis and Individuals at Risk of Rheumatoid Arthritis Compared to Healthy Individuals. Arthritis Rheumatol. 2021;73(11):1986-1993. doi:10.1002/art.41780