Intrinsic AD shows similar Th2 but higher Th17, Th1, and Th22 immune activation compared with extrinsic AD, with higher amounts of the inflammatory IL-17, CXCL8, IFN-γ, and IL-22 cytokines and related chemokines in intrinsic AD lesional skin (79) (Figure 2). This evidence concerns the gene IL17A and Alzheimer disease.