Neutrophil Extracellular Traps in the Second Decade

Abstract

Nearly 15 years after the first description of neutrophil extracellular traps (NETs), our knowledge concerning this structure has expanded considerably. Initially, NETs were considered solely an elaborate function of the innate immune system to combat invading microorganisms. Successively it became clear that NETs have farther-reaching capabilities. They are involved in a series of pathophysiological mechanisms ranging from inflammation to thrombosis where they fulfill essential functions when produced at the right site and the right time but can have a serious impact when generation or clearance of NETs is inadequately controlled. This review provides a concise overview on the far-reaching functions of NETs in health and disease.

Keywords: Autoimmunity; Bacterial infection; Cancer; Coagulation; Extracellular traps; Inflammation.

Fig. 1

Scanning electron micrograph of purified human neutrophils that have produced NETs after cocultivation with P. aeruginosa for 3 h. Scale bar, 1 µm.

Fig. 2

Paraffin section of a C. albicans– infected mouse lung stained for neutrophil elastase (a, green in c) and histone 2B (b, red in c). The depicted area is rich in neutrophils that have partly formed NETs (arrows). The image is a 3-D reconstruction of a confocal stack. The side length of the squares in the background is 10.66 µm.