CCL17 and Alzheimer disease: While little is known about the alterations in skin-derived immunity and skin barrier function that occur during the early-onset phase of AD, Th2 (IL-13, IL-31, and CCL17), Th22 (IL-22 and S100As), and some Th1-skewing (IFN-γ and CXCL10) have been detected in the skin, which is also observed in adults [38].