Interleukin-8 (IL-8) is a chemokine produced by macrophages and other cell types such as epithelial cells. It is also synthesized by endothelial cells, which store IL-8 in their storage vesicles. IL-8 is one of the major mediators of the inflammatory response. This chemokine is secreted by several cell types. It functions as a chemoattractant, and is also a potent angiogenic factor. Gene of IL-8 is believed to play a role in the pathogenesis of bronchiolitis. While neutrophil granulocytes are the primary target cells of IL-8 there is a relative wide range of cells (endothelial cells, macrophages, mast cells, keratinocytes) responding to this chemokine, too. When first encountering an antigen, the primary cells to encounter it are the macrophages that phagocytose the particle. Upon processing, they release chemokines to signal other immune cells to come in to the site of inflammation. IL-8 is one such chemokine. It serves as a chemical signal that attracts neutrophils at the site of inflammation, and therefore is also known as Neutrophil Chemotactic Factor. Interleukin-8 is often associated with inflammation. As an example, it has been cited as a proinflammatory mediator in psoriasis.¹

<0.15 ng per 1 µg as determined by the LAL method