IL6 and rheumatoid arthritis: During inflammation, IL-1 enhances an IL-6-induced shift of the Treg/Th17 balance towards Th17 cells [3], and RA promotes, in the presence of IL-15, the secretion of IL-12 and IL-23 by DC, inducing the IFN-γ-producing Th1 and Th17 cells, and enhances the IL-4-mediated induction of Th2 [3, 18, 140].