TNF and rheumatoid arthritis: Tumor necrosis factor inhibitors (TNFi) were the first biological disease-modifying antirheumatic drugs (bDMARDs) used for rheumatoid arthritis (RA), and evidence has accumulated regarding the safety, effectiveness, and tolerability of adalimumab (ADA), etanercept (ETN), and infliximab (IFX) [1–5].