IL-8, also known as CXCR8, is a member of the CXC family of chemokines and is expressed by many cell types including monocyte/macrophages, T cells, neutrophils, fibroblasts, endothelial cells, keratinocytes, hepatocytes, chondrocytes, and various tumor cell lines. IL-8 is a neutrophil chemoatractant and activating factor, and signals through CXCR1 and CXCR2 receptors.