IL-33 is a member of the IL-1 family with a high expression in the central nervous system compared to other organs and functions to induce immune cells to produce type 2 cytokines (including IL-4, IL-5, IL-6, IL-10, and IL-13) [153]; as such, activation of ST2 by IL-33 results in protective effects against cognitive impairment caused by POCD [152] and stroke [154] in mice. The gene discussed is IL33; the disease is stroke disorder.