Interleukin-8 (IL-8) is a chemokine, a member of the cytokine family that displays chemotactic activity for specific types of leukocytes. It is a proinflammatory CXC chemokine that can signal through the CXCR1 and CXCR2 receptors. Many cell types, including monocyte/macrophages, T cells, neutrophils, fibroblasts, endothelial cells, keratinocytes, hepatocytes, chondrocytes, and various tumor cell lines, can produce CXCL8/IL-8 in response to a wide variety of pro-inflammatory stimuli such as exposure to IL-1, TNF, LPS, and viruses.