Although this suspicion was almost resolved by the discovery of IgE-bearing LCs [55] and the introduction of the concept of IgE-mediated delayed-type hypersensitivity [56], the question still remains because IgE expression on LCs is not a feature specific to patients with AD; it also occurs in patients with other inflammatory skin diseases involving serum hyper-IgE [57]. Here, IGHE is linked to Alzheimer disease.