TY -的T1 -网在肺炎:足够的the right amount? JF - European Respiratory Journal JO - Eur Respir J DO - 10.1183/13993003.00619-2018 VL - 51 IS - 4 SP - 1800619 AU - Gray, Robert D. Y1 - 2018/04/01 UR - //www.qdcxjkg.com/content/51/4/1800619.abstract N2 - Neutrophil extracellular traps (NETs) form when stimulated neutrophils undergo an oxidative burst and emit a complex of DNA, histones, pro-inflammatory and antibacterial proteins in a process distinct to other forms of neutrophil disposal such as apoptosis or necrosis. NETs have been associated with a number of important disease processes ranging from infectious diseases to sterile inflammatory conditions. This multi-potent role in immunity has led to conflicting opinion and evidence as to the beneficial or detrimental effects of NETs in immunity and indeed whether they have a major role in humans is as an antimicrobial defence [1]. In this issue of the European Respiratory Journal, Ebrahimi et al. [2] demonstrate an association between high levels of nucleosomes (a marker of NETs) and adverse outcome in community-acquired pneumonia (CAP), in terms of time to patient stability, length of intravenous antibiotic treatment and time to discharge. Additionally, and perhaps more importantly, those with the highest levels of NETs had a higher (all cause) mortality. Interestingly, when the effects of corticosteroids on CAP outcome were investigated in this cohort, although these patients had a better clinical outcome they had higher persisting levels of NETs at days 5 and 7 (a feature also seen in the placebo arm of the trial where slower to decline levels of NETs were associated with better outcome), albeit they had started at a lower baseline. This presents a dichotomy where high levels of NETs (at presentation and over the course of CAP) are associated with bad outcome and death, whereas persisting lower levels of NETs into recovery are associated with better outcome. We might speculate that excessive levels of NETs in CAP could represent patients with a higher level of neutrophil activation in response to more severe infections or indeed patients with a higher level of systemic inflammation (a feature previously shown to be associated with adverse outcome in CAP [3]), but the clinical and pathological significance of slower to resolve NETs are less clear. Nevertheless, the present study suggests that the measurement of NETs may be a powerful biomarker of outcome in CAP. The authors go further in suggesting that excessive NETs at baseline and an early exhaustion of NET formation in the context of severe CAP is a potential mechanism leading to poor patient outcome; however, this remains speculative and further mechanistic studies will be required to investigate this feature. So, is there an optimal level of NETs at which health is maintained and too many or too few are detrimental?NETs have been suggested to have both detrimental and beneficial roles in lung infection and inflammation. The reality probably lies somewhere in the middle, where adequate NETs are needed to help control infection but excessive NETs cause damage http://ow.ly/IKH130jqFP3 ER -