Interleukin-8 (IL-8), also known as CXCL8, GCP-1 and NAP-1, is a proinflammatory chemokine belonging to the intercrine alpha (chemokine CXC) family. It is secreted by monocytes, macrophages and endothelial cells. IL-8 signals through CXCR1 and CXCR2 to chemoattract neutrophils, basophils, and T cells. IL-8 is also a potent promoter of angiogenesis. Other functions of this protein, such as involvement in bronchiolitis pathogenesis, have also been reported.