In terms of the increased thickness of the epidermis in the atopic samples after allergen exposure, it is important to point out that keratinocyte activation and proliferation is a characteristic of AD [26,27,28] and is linked to T helper 2 cytokines like IL-4 and IL-13, which act as growth factors for keratinocytes and increase proliferation [28,29,30]. This evidence concerns the gene IL4 and Alzheimer disease.