CCL27 and Alzheimer disease: Specifically, the CXCR3–CXCL9/CXCL10/CXCL11 and CCR4-CCL17/CCL22 systems play important roles in CHS development; the CCR10–CCL27, CX3CR1–CX3CL1, and CCR4–CCL17/22 pathways are related to the pathogenesis of type 2 inflammation in AD skin, and the CCR4–CCL17/CCL22 and CCR6/CCL20 axis show promising potency in the treatment of psoriasis.