In AD lesions, IL-22 plays a more complex role, the expression of many genes encoding Th2 cell-associated (IL-4, IL-10, and IL-13) and Th22 cell-associated (IL-22) proteins are upregulated, which is mostly related to keratinocyte activity and T cell infiltration, a previous study has shown that IL-22 acts by activating keratinocytes and limiting their differentiation [39, 40]. Here, IL4 is linked to Alzheimer disease.