Despite its relative success, only around 60% of patients with severe RA have any measureable decrease in disease activity in response to TNF inhibitor (TNF-i) therapy, and only 30–40% achieve a low disease state, as classified by DAS28 scores (28-joint Disease Activity Score) below 2.6 (Kihara et al., 2017). This evidence concerns the gene TNF and rheumatoid arthritis.