抄録
Interleukin-33 (IL-33) belongs to the IL-1 family of cytokines and has been reported to play multiple roles in host defense, allergies and chronic inflammation. Constitutive expression of IL-33 in epithelial cells ensures rapid immune responses against invading pathogens such as parasites and viruses. Tissue damage caused by pathogens results in the release of extracellular IL-33 that in turn alerts a variety of immune cells such as group 2 innate lymphoid cells (ILC2s), eosinophils, basophils and mast cells. These cells mediate T helper type 2 (Th2) immune responses to destroy pathogens. IL-33 also plays central roles in mediating allergic diseases including asthma and atopic rhinitis. Although the functions of IL-33 in host defense and allergies initially received most attention, focus is turning to its roles in chronic inflammatory diseases. Recent advances, however, have led to problematic results. In addition to Th2 responses, IL-33 also promotes Th1 responses and there have been positive and negative roles reported for IL-33 in inflammatory diseases. This mini-review will summarize IL-33 biology and discuss issues regarding previously unrecognized roles of IL-33.
