This is a mechanistic study examining changes in repertoires of both T cell receptors (TCR) and B cell receptors (BCR) in patients with RA initiating ABA treatment and who are followed for 6 months relative to changes in repertoires of both TCRs and BCRs in two similarly followed comparator groups: . Patterns of T and B cell repertoires in the group of patients with RA initiating treatment with ABA will be compared to (i) RA patients on stable therapy with methotrexate (MTX) or leflunomide (LEF) with or without TNF inhibitors and (ii) controls matched for age (+/- 7 years) and sex (approximately 75% female +/- 5%). Our primary hypothesis is that ABA treatment will affect the immune repertoires both in TCR and BCR and the distribution of immune cell subsets (particularly B cell subsets) over time to a greater extent than non-ABA treated RA patients and controls.~The goal is to determine how abatacept changes the repertoires of both TCRs and BRCs compared to control groups. The investigators anticipate that the repertoires will change differently in ABA treated patients over time relative to similar RA patients treated with conventional synthetic DMARDS (MTX and / or Leflunomide), with or without the use of a TNF inhibitor (TNFi). Changes in repertoires will also be compared to controls with no inflammatory disease.with proportionately similar proportions of anti-CCP3 positivity, (but not anti-IL-6 therapy, Jak Kinase Inhibitors (JAKi's) or Rituximab)~A total of 72 people will participate in this study at HSS in three separate arms:~Arm 1: Patients beginning abatacept as a treatment for their RA~Arm 2: Patients beginning a TNF inhibitor as a treatment for their RA~Arm 3: Healthy volunteers (free from autoimmune or connective tissue disease)~Once enrolled, these participants will be assessed at their baseline visit and seen 3 months and 6 months after baseline. These visits will involve a blood draw and questionnaires related to functioning and feeling with RA (where applicable) and may take up to an hour. Participants will be compensated per visit.
The condition that will be studied is Rheumatoid Arthritis (RA), and in particular, RA patients with moderate to highly active disease who were prescribed Abatacept (Orencia®) (ABA) by their physician during their setting of care at Hospital for Special Surgery (HSS). This investigator-initiated, prospective, comparative, 3-arm observational study will examine changes in lymphocytes in RA patients starting abatacept compared to RA patients starting TNF inhibitors and to healthy controls. This will help investigators to learn more about the processes that cause joints to swell and hurt. This may also offer clues that might predict which patients will have a good or poor response to these treatments.