Interestingly, when we tested expression of genes that show substantial changes in transgenic mice associated with AD (43,44) a number of aspects of gene expression were mimicked by anti-inflammatory IL-4 stimulation, particularly the increased expression of genes associated with the neurodegenerative signature, including Igf1, Itgax, Clec7a and Arg1 (58,59,61,84,86). The gene discussed is ARG1; the disease is Alzheimer disease.