IL18 and cryopyrin-associated periodic syndrome: IBD differs fundamentally from classical autoinflammatory diseases such as familial Mediterranean fever (FMF), Blau syndrome, and cryopyrin-associated periodic syndromes (CAPS), which are primarily caused by gain-of-function mutations in inflammasome-related genes and are characterized by excessive production of interleukin (IL)-1β and IL-18 [33].