This concept is most strongly supported by members of the IL-1 family of cytokines in the pathogenesis of IBD (Table 1) (9, , , , , , , , , , , , –22), where the same cytokine can possess both classic pro-inflammatory properties, as well as protective, anti-inflammatory functions, which is primarily dependent on the presence of receptor-bearing cells during the host’s disease state. Here, IL1A is linked to inflammatory bowel disease.