IL6 and rheumatoid arthritis: A cascade of inflammatory reactions plays a critical role in the pathological microenvironment of RA, and the proinflammatory cytokines including tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and prostaglandins (PGE2) would abundantly express in the rheumatoid joint cavity36,37.