When the downregulated genes in microglia of MNU-treated Trem2−/− retina was compared with markers of DAM identified in the brain of AD mouse [15], a group of 40 genes were found in common, including Spp1, Lpl, Mif, Fabp3 and Fabp5, which are related to lipid metabolism and phagocytosis (Fig. 5A, B). The gene discussed is MIF; the disease is Alzheimer disease.