Newly discovered species of bacteria in the microbiome may be a culprit behind rheumatoid arthritis

Rheumatoid arthritis affects 1 in 100 people worldwide. It causes inflamed, painful and swollen joints, often in the hands and wrists, and can lead to loss of joint function as well as chronic pain and joint deformities and damage. What causes this condition has been unknown.

In our recently published study, my colleagues and I found an important clue to a potential culprit behind this disease: the bacteria in your gut.

What causes rheumatoid arthritis?

Rheumatoid arthritis is an autoimmune condition, meaning it develops when the body’s immune system starts to attack itself. Proteins called antibodies, which usually help fight off viruses and bacteria, begin to attack the joints instead.

The origins of the antibodies that cause rheumatoid arthritis have been an area of study for many years. Some research has shown that these antibodies can start forming at sites like the mouth, lung and intestines over 10 years before symptoms arise. But until now, it was unclear why researchers were finding these antibodies in these particular areas.