Interleukin 1-alpha (IL-1α), also named hematopoietin 1, is a 17.65 kDa cytokine with 159 amino acid residues. IL-1α is mainly expressed in macrophages, neutrophils, epithelial cells, and endothelial cells. When IL-1α binds to the IL-1 receptor, It mediates a wide variety of biological processes such as cell division, angiogenesis, production of interleukin-2, and cellular sodium ion homeostasis. In addition, IL-1α also plays a critical role in immune responses, such as fever and inflammation, and triggers tumor necrosis factor-alpha.