CCL20 and Alzheimer disease: A comparative study revealed differential expression of chemokines in AD (CCL17/18/20) and psoriasis (CXCL1, IL-8, and CCL20), indicating that disease-specific microenvironments might be involved in Th differentiation (166) While psoriasis is Th17/Th22-skewing, AD tends to be Th2/Th22 polarized (129, 166, 167).