Response to Treatment With Intravenous Abatacept Adults With Rheumatoid Arthritis

The immune system of patients with Rheumatoid Arthritis (RA) is different from that of people who do not have RA. The purpose of this study is to examine immune cells and proteins before subjects start to take study medication and after subjects start treatment with an approved therapy for RA, abatacept that will be given in combination with Methotrexate and/or anti‐rheumatic drugs (DMARDS) that are approved for the treatment of RA. This study will assess whether subjects have clinically responded to these medications. This assessment will also include a study of whether characteristics of the subject's immune system were changed by therapy with the study drug, abatacept.