To investigate molecular signals that induce the proliferation of homeostatic microglia in the AD + Toxo group, microglial trophic factors (IL-1β and TNF-α) and inducers (IFN-γ and IL-4) for polarization of M1 and M2 microglia were examined using ELISA and microarray analysis (Figure 2H,I). This evidence concerns the gene IL4 and Alzheimer disease.