Jak3 knockout mouse model showing Il-2, Il-4, Il-7, Il-9, and Il-15 conduction defects, elevated levels of Il-6 and Il-17a and severe immunodeficiency, defects in barrier function lead to Ulcerative colitis (UC) (Baird et al., 1998; Mishra et al., 2013). Here, IL9 is linked to ulcerative colitis.