How Neutrophils Meet Their End

Neutrophil death can transpire via diverse pathways and is regulated by interactions with commensal and pathogenic microorganisms, environmental exposures, and cell age. At steady state, neutrophil turnover and replenishment are continually maintained via a delicate balance between host-mediated responses and microbial forces. Disruptions in this equilibrium directly impact neutrophil numbers in circulation, cell trafficking, antimicrobial defenses, and host well-being. How neutrophils meet their end is physiologically important and can result in different immunologic consequences. Whereas nonlytic forms of neutrophil death typically elicit anti-inflammatory responses and promote healing, pathways ending with cell membrane rupture may incite deleterious proinflammatory responses, which can exacerbate local tissue injury, lead to chronic inflammation, or precipitate autoimmunity. This review seeks to provide a contemporary analysis of mechanisms of neutrophil death.