[Interleukin-33: from biology to potential treatments].

Interleukin-33 is a member of the IL-1 cytokine family, expressed in the nucleus of endothelial cells and epithelial cells of barrier tissues. After cellular damage, IL-33 is released in the extracellular space and functions as an alarmin that alerts the immune system. IL-33 plays a critical role in type-2 innate immunity and allergic inflammation, by activating various target cells including mast cells and innate lymphoid cells that secrete high amounts of IL-5 and IL-13, two cytokines involved in allergic reactions. Recent studies suggest that IL-33 can also play other important roles, for example in homeostasis and during viral infection. It is implicated in numerous diseases, including allergic, inflammatory and infectious diseases and it constitutes a promising therapeutic target for treatment of severe asthma.