Rheumatoid arthritis (RA) is a debilitating autoimmune condition that affects millions of people across the globe (1). The ultimate cause of RA is largely mysterious. While researchers have long suspected that the microbiome influenced development of the disease, the specific microbe (or microbes) has eluded identification.
Now, in a recent Science Translational Medicine paper, researchers reported a strain of Subdoligranulum bacteria that may drive RA development (2). Some people at risk for the disease have antibodies against this bacteria, and Subdoligranulum activation of T cells was more prevalent in people with RA than in healthy controls. Perhaps even more intriguingly, mice given this bacterium developed a condition similar to human RA.
Identifying this bacterium was no simple task. First, the research team, a collaboration between scientists at the University of Colorado, Stanford University, and the Benaroya Research Institute, screened blood donated by people at risk for RA or with early-stage ...
