TNFRSF1A and rheumatoid arthritis: Infliximab (RemicadeTM), a blocking chimeric monoclonal antibody, and etanercept (EnbrelTM), a fusion protein consisting of the soluble portion of the p75-TNF receptor (TNFR) and the Fc fragment of human IgG1 (hinge, CH2 and CH3 domain), were the first TNF-specific biological therapeutics to make a substantial impact for the treatment of RA.