Neutrophil Elastase (ELA2), also known as polymorphonuclear leukocyte elastase, is a serine protease belonging to the chymotrypsin family. Located primarily in the azurophil granules of polymorphonuclear leukocytes, ELA2 function results in the degradation of many extracellular matrix macromolecules. Alpha-1 Antitrypsin (Serpin A1) and secretory leukocyte protease inhibitor (SLPI) have been shown to inhibit ELA2 activity. ELA2 may be involved in lung emphysema, cystic fibrosis, the adult respiratory distress syndrome (ARDS), rheumatoid arthritis, tumor invasion and infectious diseases