Interleukin-8 (IL-8)

The chemokines can be divided into two subfamilies depending on whether the first two cysteines are adjacent (C-C chemokines) or not (C-X-C chemokines). IL-8 is a member of the second subfamily. IL-8 is a non-glycosylated protein of 8 kDa (72 amino acids) and it is produced by the processing of a precursor protein of 99 amino acids. Monocytes, macrophages, neutrophils, lymphocytes, dermal fibroblasts, keratinocytes, vascular endothelial cells, melanocytes, hepatocytes and various tumor cell lines produce IL-8. IL-8 is present in the synovial fluids of patients with rheumatoid arthritis and has been purified from plaque psoriasis scales. It is associated also with sepsis, asthma and glomerulonephritis. Elevated levels of IL-8 have been discovered after sublethal endotoxaemia, septic shock, microbial infection of the amniotic cavity, Jarish-Herxheimer reaction of relapsing fever, infectious diseases of the central nervous system, acute pancreatitis, ulcerative colitis, empyaema, haemolitic uraemic syndrome, meningococcal disease, gastric infection, pertussis, and peritonitis. IL-8 will be clinically important in understanding disease states that are characterized by neutrophil infiltration.