TNF and rheumatoid arthritis: Etanercept, a tumor necrosis factor-alpha (TNF-α) receptor antagonist, in combination with methotrexate has shown to be more effective than etanercept or methotrexate alone for control of disease activity in patients with rheumatoid arthritis (RA).1 With the development of new targeted therapies for RA there is a need for more sensitive and specific assessment of treatment response.