TNF and rheumatoid arthritis: Since the first report of the tumor necrosis factor-α inhibitor (TNF-i) infliximab as the first biological disease-modifying antirheumatic drug (bDMARD) for treatment of RA in 1993 [2], bDMARDs, including several TNF-i [2–5], tocilizumab (TCZ) as an interleukin 6 (IL-6) inhibitor [6, 7], anakinra as an IL-1 inhibitor [8], abatacept (ABT) as a T cell co-stimulator inhibitor [9], and rituximab as a B cell depleting monoclonal antibody [10], have become available, and innovative progress in RA treatment has been made due to their potent clinical efficacy.