Interleukin 1 (IL-1) is a name that designates two proteins, IL-1 alpha and IL-1 beta, which are the products of distinct genes, but which show approximately 25% amino acid sequence identity and which recognize the same cell surface receptors. IL-1 production is generally thought to be associated with inflammation, but it has also been shown to be expressed during kidney development, thymocyte differentiation and cartilage degradation. IL-1 has also been implicated in several pathological conditions including rheumatoid arthritis, inflammatory bowel disease and atherosclerosis.
