IL9 and colitis: For example, studies on mouse models have shown that mAbs directed against IL-12 and IL-23 p40 can improve the severity of colitis; similarly, mAb against IL-21 leads to a downregulation of the infiltration of T cells in the colon and of some proinflammatory cytokines, such as IL-6 and IL-17A in the inflamed intestine in mice with colitis induced by dextran sulfate sodium (DSS) [52,53].