Figure 1.

The pathological role of IL-6 in RA.

Notes: The pathogenesis of rheumatoid arthritis is composed of a priming phase and an effector phase. In the priming phase, IL-6-induced Th17 development and the induction of autoantibodies such as rheumatoid factor (RF) are important. Th17-dependent immune activation generates active synovitis. Synovitis is an epicenter of the inflammation of RA. Systemic inflammation (production of acute phase protein, anemia and fatigue) is mainly mediated by IL-6. Local inflammation (arthritis) such as arthralgia, swelling, and joint destruction is mainly mediated by TNF.