Nick J Lepore

Plain English
Researchers found that a protein called CD13, which is released into fluid in inflamed joints, promotes the growth of new blood vessels and attracts immune cells to the joint—both hallmarks of rheumatoid arthritis. The protein works through its structure rather than its enzymatic function, and when injected into mouse knees, it triggered joint swelling and inflammation. This discovery suggests that blocking CD13 could be a new way to treat rheumatoid arthritis and other inflammatory joint diseases.

Plain English
Researchers studied a protein called CD13 found in joint tissues of people with rheumatoid arthritis (RA). They found that CD13 is more abundant in the joint fluid of RA patients compared to those with osteoarthritis and that it can be released from cells in a way that may promote inflammation and cell growth. Specifically, they identified that certain proteins (metalloproteinases) help release CD13 from the surface of cells, and blocking CD13 reduced cell growth and movement, indicating it plays a role in the disease's harmful effects. Who this helps: This research helps patients with rheumatoid arthritis and their doctors by providing insights into a potential target for treatment.