Interleukin 8 (IL-8) is a chemokine produced by macrophages and other cell types such as epithelial cells, airway smooth muscle cells, and endothelial cells, and, in humans, is encoded by the IL8 gene.IL-8 potently promotes angiogenesis, which plays an important role in the pathogenesis of bronchiectasis.IL-8 may modulate the inflammatory response through the convening and degranulation of neutrophils, and may act as an autocrine growth factor in colorectal cancer cell lines. High levels of IL-8 reduce positive responses to antipsychotics in patients with schizophrenia. In addition, IL-8 is associated with the pathogenesis of obesity and cystic fibrosis.