TGFB1 and autoimmune disease: IL-6 in the presence of TGF-β promotes naïve T-cell differentiation into Th17 cells, while IL-6 inhibits TGF-β-induced regulatory T-cell (Treg) differentiation [5], causing imbalance between Th17 and Treg, which is a primary pathogenic factor in several autoimmune diseases [6].