Since serum IgE level is correlated with the severity of AD (Arshad and Holgate, 2001; Belloni et al., 2008; Ibler and Jemec, 2015; Montes-Torres et al., 2015), and the level of IgE is associated with Th2 or Th1 immunity (Snapper and Paul, 1987), we examined the serum level of IgE to evaluate the effect of fluoxetine on systemic Th1 and Th2 immunities in DNCB-treated mice. Here, IGHE is linked to Alzheimer disease.