TNF and rheumatoid arthritis: As tumor necrosis factor-alpha (TNF-α) has a principal role in the pathogenesis of RA, anti-TNF-α biologic agents have brought marked clinical achievement in RA patients.3 Moreover, interleukin (IL)-1 and IL-6 blockades have been introduced because these cytokines are reported to be involved in the pathogenesis of RA.4 However, despite the widespread use of targeted therapies, up to 50% of patients with RA still fail to respond adequately.