IL6 and colitis: Moreover, Tec regulated the expression of Il23r in vitro at low IL-6 concentration during Th17 differentiation, and the levels of IL-23R on pre- and postconversion Th17 cells in vivo during colitis, implying that by restraining IL-6 signaling, Tec also restrains STAT3 phosphorylation, IL-23 receptor levels, and therefore full differentiation and plasticity of Th17 cells.