For example, it is now known that infiltration of immune cells (e.g., T cells, mast cells, and dendritic cell subtypes) is increased in AD lesions, the serum IgE level is elevated in AD patients compared to that in patients affected by several inhaled allergens, and the increase of secreted Th2 helper cytokines is highly correlated with the disease [2,5,6]. Here, IGHE is linked to Alzheimer disease.