Scientists peek inside immune system to see why some arthritis drugs work better

This study is for people with rheumatoid arthritis who are starting a drug called abatacept (Orencia). Researchers want to see how this drug changes certain immune cells (T and B cells) in the blood over 6 months. They will compare these changes to those in people taking other arthritis drugs and in healthy volunteers. The goal is to learn more about why joints swell and hurt, and possibly find clues to predict who will respond well to treatment.