Is interleukin-1 increased in fever?

IL 1. Interleukins are cytokines. These are chemical substances released by one cell (often inflammatory), which influence the behavior of other cells. Several interleukins, particularly il 1, are known as pyrogens, in that they may induce fever. Since the interactions among these are quite complex it is possible that the fever was induced by one pyrogen which also caused release of il 1.