FLG and Alzheimer disease: In patients with AD, type-2 inflammation-promoting chemokines (including thymic stromal lymphopoietin [TSLP], IL-25, and IL-33) can be released from keratinocytes by the following pathogenesis: epidermal barrier dysfunction (due to genetic factors such as filaggrin mutations and extrinsic factors such as low humidity), environmental stimuli (e.g., scratching and dysbiosis of S. aureus), and recognition of the innate immunity activation signals via receptors (e.g., toll-like receptors).