The localization of several neutrophil enzymes with proinflammatory function, like elastase, myeloperoxidase (MPO) or proteinase 3, to NETs and the increasing evidence for the implication of NETs in non-infectious diseases, including asthma [25], ulcerative colitis [26] and systemic lupus erythematosus (SLE) [27]–[29], suggest a role for the formation of these structures in the amplification of the inflammatory responses that characterize these disorders. This evidence concerns the gene MPO and infectious disease.