T Cells and TNF (Tumor Necrosis Factor): The Impact of TNF Blockade

Inclusion criteria: * Only anti-TNF naïve patients will be included in this study * Patients between 18 to 80 years of age * Patients due to start treatment with anti-TNF blocking agents - etanercept or adalimumab Patients with rheumatoid arthritis * Only patients meeting the 1987 American College of Rheumatology (ACR) revised classification criteria for rheumatoid arthritis will be included * Patients should have active rheumatoid arthritis, defined by an initial DAS28 score \>5.1 * Patients should have at least 1 joint suitable for synovial biopsy * Patients can be on concurrent DMARDs but they should have been on a stable dose of DMARD for at least 1 month prior to study entry * Patients can be on a concurrent dose of glucocorticoids (up to 10mg daily) and they should have been on a stable dose for at least 4 weeks prior to study entry Patients with psoriatic arthritis * Patients should have a secure diagnosis of psoriatic arthritis determined by a rheumatologist * Patients with psoriatic arthritis included in this study should have evidence of concurrent psoriatic skin lesions at the time of study entry * Patients should have at least one joint suitable for synovial biopsy * Patients can be on concurrent DMARDs - they should be on a stable dose of DMARD for at least 1 month prior to study entry Patients with Ankylosing spondylitis * Patient should fulfil the Modified New York Criteria for diagnosis of ankylosing spondylitis * Patients can be on concurrent NSAIDs * Patients can be on concurrent DMARDs - they should be on a stable dose of DMARD for at least 1 month prior to study entry Exclusion Criteria: * Patients who have been previously treated with anti-TNF therapy for whatever reason * Patients with rheumatoid arthritis, psoriatic arthritis or ankylosing spondylitis who do not fulfil the diagnostic criteria for these conditions as above * Patient who have received an intra-articular injection of steroids or have received an intra-muscular injection of depot steroid to treat disease flare in the preceding 4 weeks prior to commencing anti-TNF therapy. * Patients with intercurrent, active infection of any type, excluding the common cold