IL1RL1 and Alzheimer disease: IL-33 released by keratinocytes, endothelial cells and other immune cells activates ST2, followed by the activation of MyD88 and expression of factors implicated in several inflammatory pathways.3, 24, 25, 26 To define which cell type is involved in AD development, we used cell-specific MyD88-deficient mice using the cre-lox system27 and found that MC903-induced AD syndrome was drastically reduced in DC-specific MyD88 (CD11c-cre × MyD88-floxed) deficient mice.