IL4 and Alzheimer disease: In the skin of AD patients, macrophages are exposed to a complex array of stimuli, including type 2 cytokines (e.g., IL-4, IL-13), microbial components (e.g., S. aureus-derived peptidoglycan), neuropeptides (e.g., neuropeptide Y), histamine, lipid mediators, and mechanical stress, which shape their activation states dynamically (10).