Translational research : the journal of laboratory and clinical medicine
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In a process known as overt degranulation, mast cells can release all at once a diverse array of products that are preformed and present within cytoplasmic granules. This occurs typically within seconds of stimulation by environmental factors and allergens. These potent, preformed mediators (ie, histamine, heparin, serotonin, and serine proteases) are responsible for the acute symptoms experienced in allergic conditions such as allergic conjunctivitis, allergic rhinitis, allergy-induced asthma, urticaria, and anaphylaxis. ⋯ Mast cells can trigger actions and chemotaxis in other important immune cells (eg, eosinophils and the newly discovered type 2 innate lymphocytes) that then make their own contributions to inflammation and disease. In this review, we will discuss the many known and theorized contributions of mast cells to allergic diseases, focusing on several prototypical allergic respiratory and skin conditions: asthma, chronic rhinosinusitis, aspirin-exacerbated respiratory disease, allergic conjunctivitis, atopic dermatitis, and some of the more common medication hypersensitivity reactions. We discuss traditionally accepted roles that mast cells play in the pathogenesis of each of these conditions, but we also delve into new areas of discovery and research that challenge traditionally accepted paradigms.