Increased expression of mouse and/or human IL-33 has been observed during inflammation such as asthma [22,48,49] chronic obstructive pulmonary disease (COPD) [28], ulcerative colitis [50,51], fibrosis [52] or after parasite infestation or virus infection, such as influenza [53,54], RSV [55,56] as well as after allergen exposure or in allergic patients [57,58,59,60], after a hypo-osmotic stress [61] or exposure to cigarette smoke [53]. This evidence concerns the gene IL33 and asthma.