In the current study, there were some dogs with clinical features of AD but an undetectable IgE response to allergens; this can be explained by the possible confounding problems of recruiting patients with atopic-like dermatitis or by the fact that the ASIS testing cannot detect the presence of cutaneous mast cells with reaginic antibodies present on the mast cells [25, 26]. Here, IGHE is linked to Alzheimer disease.