14 June 2023

---

Periodontal disease, more common in patients with rheumatoid arthritis

---

Exposure of the immune system to citrullinated bacterial proteins is considered a trigger for rheumatoid arthritis. The anti-citrullinated protein antibodies (ACPAs) seen in many rheumatoid arthritis (RA) patients, which serve as a diagnostic marker, may be rooted in periodontal disease, according to the researchers.

Traces of bacteria associated with periodontal disease have been found in samples collected from patients with rheumatoid arthritis. "Our findings indicate that oral mucosal barrier damage mediated by [periodontal disease] results in repeated and spontaneous translocation of oral citrullinated bacteria into the blood, which trigger innate and adaptive immune responses in RA associated with systemic disease flare-ups," the research group wrote in a study published in February 2023 in Science Translational Medicine.

This is not the first study to link RA to periodontal disease. A 2008 study found that RA patients had an eight times higher risk of having periodontitis compared to individuals without RA. Similarly, in 2019, a Korean analysis showed that while RA was not linked to periodontitis in the survey data, it was more likely in people who experienced early tooth loss. However, this study may be the first to suggest a clear causal pathway between dental infections and RA.

The researchers conducted a number of studies on several cohorts of patients. Their findings confirmed that oral bacterial components (especially of the Streptococcus species) entered the circulation at a higher rate in RA patients with periodontal disease, compared to those without. The researchers also determined that, during clinical exacerbations of RA, the expression of genes associated with the inflammatory response of monocytes in synovial tissue increased, but only in patients with periodontal disease.

Tracing the connection between the two conditions could help develop therapies for rheumatoid arthritis, while the approach that led to the study could prove fruitful in other pathological settings, such as cancer.

This article originally appeared in Odontologia33.