In AD, the unregulated and excessive production of cytokines, especially IL-4 and IL-13, causes the inhibition of the expression of epidermal proteins such as filaggrin, loricrin, and involucrin, which reinforces defects in the epidermal barrier, favoring the permeation of allergens and pathogens, feeding back the disease. The gene discussed is IL4; the disease is Alzheimer disease.