Treatment with biologic tumor necrosis factor (TNF) inhibitors such as etanercept (ETN, a human soluble dimeric TNF receptor fusion protein), adalimumab (ADL, a fully human monoclonal antibody [mAb] against TNF), and infliximab (IFX, a mouse-human chimeric mAb against TNF) [3] has significantly reduced disease activity and improved quality of life in patients with RA who have not responded to conventional disease-modifying antirheumatic drug (DMARD) therapy [4]. This evidence concerns the gene TNF and rheumatoid arthritis.