Medical Xpress – Rheumatoid arthritis (RA), which causes painful swelling of the joints, is a form of autoimmune disease where otherwise healthy tissue in a patient’s joint gets mistaken for an intruder and is attacked by the immune system.
Past observational studies have confirmed a correlation between patients with RA and higher levels of periodontal disease (gum disease).
Anti-citrullinated protein antibodies (ACPAs) are found in the blood of most patients with RA.
They are correlated so tightly that ACPAs detected in the blood are the best early detection tool for future RA pathology as they can pre-date clinical diagnosis by several years.
Gum disease is specifically more common in individuals with RA who also have ACPAs in their blood.
In a study led by Stanford University, researchers wanted to investigate whether these overlapping observations could be better connected.
Researchers analyzed bacterial RNA in blood samples collected from a group of 5 RA patients with and without gum disease over weekly time points for a year.
They identified RNA signatures within clusters of activated immune cells that correlated with both the presence of oral bacteria in the blood and with flares of arthritis in patients with both RA and periodontal disease.
The bacteria were found to be citrullinated (enzymatically altered), and this alteration provided the targets for the anti-citrullinated protein antibodies to attack …