Pathogenesis related to immune dysfunction in AD involves an increase in serum immunoglobulin E (IgE) levels, sensitization to allergens, predominance of Th2 cytokines, an increase in T cells expressing cutaneous lymphocyte-associated antigen, an increase in FcεRI expression in inflammatory dendritic epidermal cells and Langerhans cells, and increased expression of thymic stromal lymphopoietin (TSLP) (Figure 1). Here, IGHE is linked to Alzheimer disease.