Secretion of IL-4/IL-13 by Th2 cells facilitates class switching of B cells to produce allergy-specific IgE, which binds to FcεRI receptors on granulocytes, causing cross-linking of IgE upon allergen exposure, leading to degranulation and release of histamine, prostaglandins, and other inflammatory mediators. This evidence concerns the gene IGHE and Allergy.