TNF and rheumatoid arthritis: The World HealthOrganization (WHO) recognizes these diseases as among the leadingcauses of global mortality.1 Conditionssuch as rheumatoid arthritis, Crohn’s disease, psoriasis, psoriaticarthritis, and ankylosing spondylitis share common pathogenic mechanisms,with tumor necrosis factor-alpha (TNF-α) playing a central role.2,3 TNF-α is a pleiotropic cytokine produced as a 26 kDa transmembraneprotein4 that is predominantly active inits 17 kDa soluble form.