The vitamin D3 analog MC903, used to treat patients with skin cancer, has been reported to induce an AD-like syndrome, including Th2 type inflammation with eosinophilia and hyper-IgE immunoglobulinemia.19, 20, 21 In order to understand the function of IL-1 family cytokines in the pathogenesis of AD, we used MC903 to induce AD in mice. The gene discussed is IL1A; the disease is Alzheimer disease.