Inhibition of MC degranulation or blockade of the corresponding receptors of MC-derived mediators (e.g., histamine and leukotrienes) is a widely accepted symptomatic therapy.9 In addition, Th2 cytokines produced by MCs, such as IL-4 and IL-5, augment the Th2 response.10 IL-4 release increases Th2 cell induction simultaneously with IgE production.10 Therefore, degranulation of, and pathogenic IL-4 production by, MCs are essential targets for the treatment of allergic diseases. Here, IL4 is linked to allergic disease.