Zhang Fangxiao, Zhang Zhidan, Ma Xiaochun
Department of Critical Care Medicine, the First Affiliated Hospital, China Medical University, Shenyang 110001, Liaoning, China. Corresponding author: Zhang Zhidan, Email:
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue. 2017 Feb;29(2):122-126. doi: 10.3760/cma.j.issn.2095-4352.2017.02.006.
To investigate the changes of neutrophil extracellular traps (NETs) level in plasma of sepsis patients and judge its clinical value for early diagnosing of sepsis.
A prospective observational study was conducted. The patients after surgery aged > 18 years and expected to stay in the ICU > 24 hours admitted to intensive care unit (ICU) of the First Affiliated Hospital of China Medical University from November 2014 to February 2015 were enrolled. According to the criteria of sepsis diagnosis in 1991, patients were divided into non-sepsis group and sepsis group. The healthy people who taken a physical examination were enrolled in the healthy control group. 3 mL peripheral venous blood was collected at 1 hour after admission to ICU. A fasting blood was collected in the healthy control group in the morning. The plasma free DNA (cf-DNA/NETs) was determined by using the fluorescence microplate reader, white blood cell (WBC), neutrophil ratio (NEU), procalcitonin (PCT), C-reactive protein (CRP) in peripheral blood of the patients were detected, and acute physiology and chronic health evaluation II (APACHE II) and sequential organ failure assessment (SOFA) scores were calculated. The correlation between plasma NETs and the risk factors in sepsis patients was analyzed by Spearman correlation analysis. The value of cf-DNA/NETs and WBC level in the diagnosis of sepsis was analyzed by using the receiver operating characteristic curve (ROC).
Twenty-three sepsis patients, 20 non-sepsis patients, and 22 healthy persons were enrolled. There were no differences in baseline variables including gender and age among three groups, which indicated baseline data equalization. The plasma concentration of cf-DNA/NETs in sepsis group was significantly higher than that in non-sepsis group and healthy control group (μg/L: 453.44±185.37 vs. 188.35±29.66, 203.83±43.25, both P < 0.05), and there was no significant difference between last two groups (P > 0.05). WBC, NEU, PCT, CRP, APACHE II and SOFA score in sepsis group were significantly higher than those of non-sepsis group [WBC (×10/L): 9.52±5.51 vs. 5.97±2.28, NEU: 0.787±0.110 vs. 0.655±0.067, PCT (mg/L): 7.14 (3.60, 13.29) vs. 6.07 (3.57, 7.91), CRP (mg/L): 64.44±13.14 vs. 27.00±19.47, APACHE II: 10.25±4.92 vs. 6.00±1.22, SOFA: 6.0±5.1 vs. 5.0±1.2, all P < 0.05]. Correlation analysis showed that the level of NETs had no obvious correlation with gender, age, WBC, NEU, PCT, CRP, APACHE II and SOFA scores (r value was 0.322, 0.262, 0.194, 0.312, 0.227, 0.454, 0.433, 0.333, respectively, all P > 0.05). The area under the ROC curve (AUC) of plasma cf-DNA/NETs for the diagnosis of sepsis was 0.981. When the cut-off value of plasma cf-DNA/NETs was > 257.96 μg/L, the sensitivity was 91.3%, specialty was 95.2%, and Youden index was 0.865. AUC of WBC in the diagnosis of sepsis was 0.663. When the cut-off value of WBC was > 6.0×10/L, the sensitivity was 78.3% and specificity was 25.0%.
The plasma cf-DNA/NETs levels increased significantly in sepsis patients. In the diagnosis of sepsis, plasma NETs levels had better advantages over WBC. NETs can be used as a biomarker for early diagnosis of sepsis.
探讨脓毒症患者血浆中中性粒细胞胞外陷阱（NETs）水平的变化，并判断其对脓毒症早期诊断的临床价值。
进行一项前瞻性观察性研究。选取2014年11月至2015年2月在中国医科大学附属第一医院重症监护病房（ICU）收治的年龄>18岁、术后预计在ICU停留>24小时的患者。根据1991年脓毒症诊断标准，将患者分为非脓毒症组和脓毒症组。选取进行体检的健康人作为健康对照组。在患者入ICU 1小时后采集3 mL外周静脉血。健康对照组于早晨采集空腹血。采用荧光酶标仪测定血浆游离DNA（cf-DNA/NETs），检测患者外周血白细胞（WBC）、中性粒细胞比例（NEU）、降钙素原（PCT）、C反应蛋白（CRP），并计算急性生理与慢性健康状况评分系统II（APACHE II）和序贯器官衰竭评估（SOFA）评分。采用Spearman相关分析脓毒症患者血浆NETs与危险因素的相关性。采用受试者工作特征曲线（ROC）分析cf-DNA/NETs和WBC水平对脓毒症的诊断价值。
纳入23例脓毒症患者、20例非脓毒症患者和22例健康人。三组间性别、年龄等基线变量无差异，表明基线数据均衡。脓毒症组血浆cf-DNA/NETs浓度显著高于非脓毒症组和健康对照组（μg/L：453.44±185.37 vs. 188.35±29.66，203.83±43.25，均P<0.05），后两组间无显著差异（P>0.05）。脓毒症组WBC、NEU、PCT、CRP、APACHE II和SOFA评分均显著高于非脓毒症组[WBC（×10/L）：9.52±5.51 vs. 5.97±2.28，NEU：0.787±0.110 vs. 0.655±0.067，PCT（mg/L）：7.14（3.60，13.29）vs. 6.07（3.57，7.91），CRP（mg/L）：64.44±13.14 vs. 27.00±19.47，APACHE II：10.25±4.92 vs. 6.00±1.22，SOFA：6.0±5.1 vs. 5.0±1.2，均P<0.05]。相关性分析显示，NETs水平与性别、年龄、WBC、NEU、PCT、CRP、APACHE II和SOFA评分无明显相关性（r值分别为0.322、0.262、0.194、0.312、0.227、0.454、0.433、0.333，均P>0.05）。血浆cf-DNA/NETs诊断脓毒症的ROC曲线下面积（AUC）为0.981。当血浆cf-DNA/NETs截断值>257.96 μg/L时，灵敏度为91.3%，特异度为95.2%，约登指数为0.865。WBC诊断脓毒症的AUC为0.663。当WBC截断值>6.0×10/L时，灵敏度为78.3%，特异度为25.0%。
脓毒症患者血浆cf-DNA/NETs水平显著升高。在脓毒症诊断中，血浆NETs水平较WBC具有更好的优势。NETs可作为脓毒症早期诊断的生物标志物。
