Interleukin-1 (IL-1) is an extracellular peptide of 17 kDa that designates two proteins, IL-1α and IL-1β. IL-1α is a pleiotropic cytokine that in humans is encoded by the IL1A gene. IL-1α is produced mainly by activated macrophages, as well as neutrophils, epithelial cells, and endothelial cells. It possesses metabolic, physiological, haematopoietic activities, and plays one of the central roles in the regulation of the immune responses.
IL-1α has been shown to interact with HAX1 and NDN, but the most clinically relevant is its synergism with TNF. IL-1α and TNF are both acute-phase cytokines that act to promote fever and inflammation. IL-1α is currently being evaluated in clinical trials as a potential therapeutic in oncology indications. Blocking the activity of IL-1α has the potential to treat skin diseases such as acne.