We have found increased skin infiltration of Th2, ILC2, and mast cells and elevated Th2 and inflammatory cytokine expression in the cockroach allergen–induced AD-like inflammation, and DCIR–/– mast cells secreted less IL-6, IL-31, CCL2, and TNF-α relative to WT mast cells. The gene discussed is CLEC4A; the disease is Alzheimer disease.