In fact, IL-33 was shown to potently increase the production of pro-inflammatory cytokines, such as IL-5, IL-6 and IL-17, in SAMP1/YitFc mice, a mixed Th1/Th2 spontaneous model of chronic enteritis [30], whereas exogenous administration of IL-33 showed a protective effect in trinitrobenzene sulfonic acid (TNBS)-induced colitis, a chemically-induced model of colonic inflammation, mostly driven by a Th1 immune response [58]. This evidence concerns the gene IL5 and colitis.