The Interleukin-1 family (IL-1 family) is a group of 11 cytokines, which plays a central role in the regulation of immune and inflammatory responses to infections or sterile insults. In 1985 two distinct, but distantly related complementary DNAs encoding proteins sharing human IL-1 activity were reported to be isolated from a macrophage cDNA library, thus defining two individual members of the IL-1 family – IL-1α and IL-1β.