Th17 cells are characterized by the production of IL-17, which have been implicated in the pathogenesis of AD because IL-17 is crucial for the up-regulation of numerous inflammation-related genes in keratinocytes, fibroblasts, leading to the increased production of chemokines, antimicrobial peptides, and cytokines like TNF-α and IL-1β. The gene discussed is IL17A; the disease is Alzheimer disease.