Age

18–any

Sex

ALL

Healthy volunteers

Not accepted

Subject fulfils criteria for Rheumatoid Arthritis (RA) according to ACR or EULAR criteria.
Subjects who are planned to start treatment with ADA, ETA, CER or IFX
Subjects taking a minimum weekly dose of 7.5 mg of methotrexate

Patients with compliance problems
Patients who have difficulties in reading and understanding local language
Patients with Juvenile Idiopathic Arthritis (JIA)
Azathioprine or cyclophosphamide treatment within 6 months before entering into the study

Formation of Antibodies and Subsequent Prediction of Clinical Response in Patients With Rheumatoid Arthritis Treated With Four TNF Blocking Agents