Illustration of key neutrophil functions. Note that, for production reactive oxygen species, secretion of granule components, and production of cytokines and chemokines, only a few representative molecules are shown. HNE human neutrophil elastase, IL-8 interleukin-8, IL-4 interleukin-4, LF lactoferrin, MPO myeloperoxidase, TNF-α tumor nectosis factor-α