Last reviewed 01/2018

Interleukin-1, IL-1, is a glycoprotein cytokine first described in the 1940s. There are two subtypes: IL-1 alpha is intracellular and associated with antigen presentation; IL-1 beta is the main extracellular form.

IL-1 is intimately involved in immune responses and chronic inflammation. Excessive, persistent IL-1 release has been implicated in the pathogenesis of rheumatoid arthritis, cachexia and atherosclerosis.

It is produced in the following cells:

  • mononuclear phagocytes: the major source
  • antigen-presenting dendritic cells
  • neutrophils
  • B-lymphocytes
  • keratinocytes
  • endothelial cells
  • renal cells

Therapeutic administration of interleukin-1 e.g. as a cytotoxic agent, has largely been limited by side effects such as pyrexia.