IGHE and Alzheimer disease: The studied patient groups (AD, BA, and AD associated with BA) were statistically comparable in terms of serum IgE levels (500.6 ± 385.6, 655 ± 492.5, and 627.9 ± 336.6 IU/ml, respectively) and each mean value was significantly higher than that of the healthy control subjects (140.6 ± 19.7 IU/ml; P < 0.001).