Gut bacteria could be responsible for rheumatoid arthritis

Scientists have discovered a potential clue to the causes of rheumatoid arthritis, a condition that can be painful for elderly people. Researchers at the University of Colorado Anschutz Medical Campus believe the culprit could be bacteria in the gut.

Causing inflamed and swollen joints, rheumatoid arthritis affects one in 100 people across the world, but its causes have been a mystery up until now. Being an autoimmune condition, it sees antibodies attacking the joints instead of fighting off bacteria and viruses.

While previous studies have demonstrated that these antibodies can start to form in areas like the mouth, lungs and intestines more than ten years before the onset of symptoms, it’s not been known why. Now, it’s thought the gut’s microbiome could be the answer.

Once they began investigating possible triggers to the formation of the antibodies, the researchers hypothesised the microbiome might activate them. The community of microorganisms in the intestines could be spreading beyond and attacking the joints and they set out to find out if this was the case.

The first part of the process was to identify the bacteria found in the intestines that’s targeted by these antibodies. This was achieved through exposing bacteria in the faeces of participants at risk of developing rheumatoid arthritis to the antibodies and isolating those that bound to them.

A previously unknown species of bacteria was found in the intestines of 20 per cent of those with rheumatoid arthritis or those known to produce the antibodies responsible for it. They named it subdoligranulum didolesgii and acknowledged more research needs to be carried out to see how prevalent it is in the general population.

The scientists then discovered this bacteria activates T cells that produce inflammatory responses in the body. These specialised immune cells have been linked to a number of autoimmune diseases in the past.

All of this suggests subdoligranulum didolesgii bacteria could be activating the immune system in people suffering from rheumatoid arthritis. It then leads to an attack on the body’s joints, leading to painful and debilitating symptoms.

More research into this area could provide a better understanding of the origins of rheumatoid arthritis and in turn the development of treatments. It’s not thought antibiotics are the appropriate cause of action, as they’ll remove both good and bad bacteria from the gut.