IL6 and rheumatoid arthritis: The development of RA involves various inflammatory cytokines and aberrant signaling pathway transductions, such as TNF-α, IL-6, IL-1, IL-10, growth hormone, granulocyte-macrophage colony-stimulating factor (GM-CSF), transforming growth factor β (TGF-β), interferon (IFN), fibroblast growth factor-2 (FGF-2), and others.