TNF and rheumatoid arthritis: TNF was one of the first molecules selected as a target in the treatment of rheumatoid arthritis (RA) to limit chronic inflammation; infliximab is an anti-human monoclonal antibody (chimeric mouse–human) that inhibits soluble TNF in both the monomeric and trimeric form, and etanercept is a fully human recombinant molecule consisting of two subunits of the TNF receptor 2 to block the trimeric form of TNF [66].