IGHE and Alzheimer disease: As summarized in Table 1, the mean age was higher in the AD patient group than the controls (17.37 ± 3.48 month vs. 10.81 ± 2.15 month, P = 0.001), and the serum total IgE levels were significantly higher in the AD group (243.06 ± 160.21 IU/ml vs. 22.83 ± 9.46 IU/ml, P = 0.004).