Interleukin 1? encoded by IL-1? gene is a member of the interleukin 1 cytokine family. Interleukin 1? is produced by activated macrophages as a proprotein, which is proteolytically processed to its active form by caspase 1 (CASP1/ICE). Interleukin 1? is an important mediator of the inflammatory response, and is involved in a variety of cellular activities, including cell proliferation, differentiation, and apoptosis. The induction of cyclooxygenase-2 (PTGS2/COX2) by Interleukin 1? in the central nervous system (CNS) is found to contribute to inflammatory pain hypersensitivity. IL-1? gene and eight other interleukin 1 family genes form a cytokine gene cluster on chromosome 2.