CXC chemokine, interleukin 8 <p>Most members of this family of low-molecular weight proteins seem to havemitogenic, chemotactic or inflammatory activities. They are released by phagocytes, mesenchymal cells and a wide variety of tissue cells, upon exposure to inflammation [<cite idref="PUB00001646"/>]. These small cytokines are also called intercrines or chemokines. They are cationic proteins of 70 to 100 amino acid residues that share four conserved cysteine residues involved in two disulphide bonds.</p><p>The family can be split into two groups, depending on the spacing of two N-terminal Cys residues: in one group (CxC), the cysteines are separated by asingle amino acid; in the second (CC), they are adjacent [<cite idref="PUB00001373"/>]. The CxC group includes such factors as interleukin-8, platelet factor 4, melanoma growth stimulatory activity protein, macrophage inflammatory protein 2, platelet basic protein, and several others. The CC group includes the monocyte chemotactic proteins, macrophage inflammatory proteins, amongst others.</p><p>The accumulation of neutrophil leukocytes in tissues is a major event in inflammation, a defensive reaction in response to injury or infection [<cite idref="PUB00001646"/>]. Neutrophils are drawn in from the blood by chemotactic signals that direct their migration to the affected site. Interleukin-8 (IL8) is one such chemotactic protein: it is released by phagocytes, mesenchymal cells and a wide variety of tissue cells, upon exposure to inflammation; and it acts as a neutrophil-activating cytokine, inducing chemotaxis, exocytosis, and the respiratory burst.</p>