IL4 and Alzheimer disease: The common immunological characteristics of patients with AD are mast cell infiltration at the site of the lesion and elevated serum IgE levels8,36 Furthermore, Th2 and Th17 immune responses resulting from immune imbalance lead to the secretion of Th2 and Th17 cytokines (e.g., IL-4, IL-5, IL-13, IL17)5,6,37.