IGHE and Alzheimer disease: This in turn stimulates IgE-mediated activation of MCs whereby subsequent degranulation induces the release of cytokines (i.e., IL-4, IL-5 and IL-13), preformed lipid mediators namely leukotrienes and platelet activating factor (PAF) which could further intensify the progression of AD (Kulka and Befus, 2003).