IGHE and Alzheimer disease: In addition, from the perspective of the pathomechanism of allergic inflammation, AD is characterized by a transition from standard (IgE-independent) delayed-type hypersensitivity (type IV allergy) in the early stage of the disease to complex forms of allergies involving an IgE-dependent immediate response (type I allergy) [48], IgE-mediated late-phase reaction [10,46,69], and IgE-mediated delayed-type hypersensitivity [10,55,56] in the advanced stage of the disease [1].