IL4 and infection: Overexpressed in keratinocytes of AD patients, IL-33 is rapidly released in response to injury or infection, triggering Th2 polarization by activating immune cells such as mast cells and group 2 innate lymphoid cells (ILC2s) to produce IL-4, IL-5, and IL-13 (Schmitz et al., 2005; Salimi et al., 2013).