Neutrophil elastase is a serine proteinase in the same family as chymotrypsin and has broad substrate specificity. Neutrophil elastase is secreted by neutrophils during inflammation, and destroys bacteria and host tissue. It also localizes to neutrophil extracellular traps (NETs), via its high affinity for DNA, an unusual property for serine proteases. Neutrophil elastase is an important protease enzyme that when expressed aberrantly can cause emphysema or emphysematous changes. This involves breakdown of the lung structure and increased airspaces. Mutations of the ELANE gene cause cyclic and severe congenital neutropenia, which is a failure of neutrophils to mature. In 2019 study was confirmed that ELANE deletion does not cause neutropenia.