Furthermore, several biological DMARDs, including tumor necrosis factor (TNF)-α blockers, the anti-cluster of differentiation (CD) 20 monoclonal antibody, and a fusion protein consisting of the cytotoxic T-lymphocyte-associated protein-4 linked to the Fc region of immunoglobulin (Ig) G, have been used to treat RA. The gene discussed is TNF; the disease is rheumatoid arthritis.