Interleukin-8 (IL-8) was originally discovered as a neutrophil chemotactic and activating factor and is a member of the alpha (CXC) subfamily of chemokines (including also platelet factor 4, GRO, IP-10, etc.). Many cell types, including monocyte/macrophages, T cells, neutrophils, fibroblasts, endothelial cells, keratinocytes, hepatocytes, chondrocytes and various tumor cell lines, produce IL-8 in response to a wide variety of proinflammatory stimuli such as exposure to IL-1, TNF, LPS and viruses. IL-8 has a wide range of other proinflammatory effects. It is a potent chemoattractant for neutrophils and causes degranulation of neutrophil specific granules and azurophilic granules. IL-8 induces expression of the cell adhesion molecules CD11/CD18 and enhances the adherence of neutrophils to endothelial cells and subendothelial matrix proteins. Besides neutrophils, IL-8 is also chemotactic for basophils, T cells and eosinophils. IL-8 has been reported to be a co-mitogen for keratinocytes and was also shown to be an autocrine growth factor for melanoma cells. IL-8 was also reported to be angiogenic both in vivo and in vitro.