B淋巴细胞亚群上EZH2的表达对脓毒症患者预后的预测价值

目的:探讨脓毒症患者外周血B淋巴细胞（CD19 +B）、记忆B细胞亚群（CD19 +CD27 +B）上组蛋白甲基转移酶果蝇zeste基因增强子同源物2（enhance of zeste homolog 2, EZH2）动态表达变化规律及其对脓毒症患者预后判断的价值。 方法:采用前瞻性队列研究，纳入2018年6月至2020年1月在同济大学附属东方医院重症监护病房就诊的脓毒症患者48例，同期来院的40例健康体检者作为对照组。根据患者28 d存活与否将脓毒症组分为死亡组及存活组。采集确诊脓毒症1 d、3 d、7 d共3个时间点血标本（健康对照组于清晨空腹仅抽取1次），收集不同时间点脓毒症组的血常规、IL-6、血气分析等，统计SOFA和APACHE Ⅱ评分。运用流式细胞技术检测研究对象不同时间点CD19 +B细胞上EZH2阳性率及平均荧光强度、CD19 +CD27 +B细胞上EZH2的阳性率并绘制受试者工作特征曲线，计算曲线下面积，评估对判断脓毒症患者28 d死亡的预测价值。 结果:①脓毒症组确诊后第1、3、7天外周血CD19 +B淋巴细胞上EZH2的阳性率和平均荧光强度、CD19 +CD27 +B淋巴细胞上EZH2表达的阳性率较健康对照组均显著增加，且差异具有统计学意义（ P<0.05）。随着时间推移，EZH2在CD19 +B淋巴细胞、CD19 +CD27 +B淋巴细胞上表达水平呈升高趋势。②死亡组第1天CD19 +B淋巴细胞上EZH2阳性率明显高于存活组，然而死亡组第3和7天CD19 +CD27 +B细胞上EZH2的阳性率却明显低于存活组（ P<0.05）。③脓毒症患者第1天CD19 +B淋巴细胞上EZH2阳性率、APACHEⅡ评分、SOFA评分和IL-6水平均为预测患者28 d死亡的独立危险因素。④APACHE Ⅱ评分的AUC为0.907（95% CI：0.825~0.990），灵敏度为88.89%，特异度为76.67%；SOFA评分的AUC为0.831（95% CI：0.706~0.955），灵敏度为66.67%，特异度为86.67%；CD19 +B淋巴细胞上EZH2阳性率的AUC为0.799（95% CI：0.657~0.941），灵敏度为88.89%，特异度为80.77%，灵敏度优于SOFA评分，特异度高于APACHE Ⅱ评分。 结论:脓毒症患者B淋巴细胞上EZH2高表达，与患者不良预后相关；动态监测脓毒症患者B淋巴细胞上EZH2的表达有一定的临床意义。

The predictive value of the expression of EZH2 on B lymphocyte subsets on the prognosis of septic patients

Objective:To investigate the dynamic expression of histone methyltransferase (enhance of zeste homolog 2, EZH2) in peripheral blood B lymphocytes (CD19 +B) and memory B lymphocytes (CD19 +CD27 +B) of septic patients and its value in predicting prognosis in sepsis. Methods:From June 2018 to January 2020, 48 septic patients in the Intensive Care Unit of Shanghai East Hospital were enrolled, and 40 healthy adult volunteers were recruited as healthy controls. Septic patients were divided into the non-survivors (18 cases) and the survivors (30 cases) according to whether the patients survived at 28 days. Blood samples were collected at day 1, 3 and 7, blood routine, IL-6 and blood gas analysis were collected, and SOFA and APACHE Ⅱ scores were counted. Flow cytometry was used to detect the positive rate and the mean fluorescence intensity of EZH2 on CD19 +B lymphocytes, and the positive rate of EZH2 on CD19 +CD27 +B lymphocytes at different time points. In the healthy controls, fasting was taken only once in the morning. ROC curve was drawn and the area under the curve (AUC) was calculated to evaluate the value of expression of EZH2 on CD19 +B lymphocytes and CD19 +CD27 +B lymphocytes in predicting the prognosis of septic patients. Results:(1) Compared with the healthy controls, the positive rate and average fluorescence intensity of EZH2 on CD19 +B lymphocytes and the positive rate of EZH2 expression on CD19 +CD27 +B lymphocytes were significantly increased at day 1, 2 and 3 in septic patients ( P<0.05). Over time, the expression of EZH2 in CD19 +B lymphocytes and CD19 +CD27 +B lymphocytes increased gradually ( P<0.05). (2) Compared with the survivors, the positive rate of EZH2 on CD19 +B lymphocytes of the non-survivors was increased at day 1, but the positive rate of EZH2 on CD19 +CD27 +B lymphocytes of the non-survivors was decreased at day 3 and 7 ( P<0.05). (3) The positive rate of EZH2 on CD19 +B lymphocytes, APACHE Ⅱ score, SOFA score and IL-6 level in septic patients at day 1 were independently associated with 28-day mortality. (4) The AUC of APACHEⅡ score was 0.907 (95% CI: 0.825-0.990), and the sensitivity and the specificity were 88.89% and 76.67%. The AUC of SOFA score was 0.831 (95% CI: 0.706-0.955), and the sensitivity and the specificity was 66.67% and 86.67%; The AUC of EZH2 positive rate on CD19 +B lymphocytes were 0.799 (95% CI: 0.657-0.941), and the sensitivity and specificity were 88.89% and 80.77%, respectively, the sensitivity was better than SOFA score, and the specificity was higher than APACHEⅡ score. Conclusions:The high expression of EZH2 on B lymphocytes in septic patients is associated with poor prognosis. Dynamic monitoring of EZH2 expression on B lymphocytes has certain predictive value for sepsis.