摘要目的:探讨与儿童脓毒症发生院内感染相关的免疫指标。方法:回顾性研究。选择2015年9月至2020年6月上海儿童医学中心儿童重症监护室（PICU）诊断脓毒症的155例患儿为研究对象，根据在PICU期间有无发生院内感染，分为无院内感染组和院内感染组，比较两组辅助性T细胞1和2细胞因子、T细胞亚群绝对计数、外周血CD14 +单核细胞人类白细胞DR抗原（CD14 +HLA-DR）表达比例、调节性T细胞比例、第三代小儿死亡危险评分（PRISM-Ⅲ）及治疗转归。通过倾向性评分匹配（PSM），对无院内感染组和院内感染组两组的病情严重度及治疗进行匹配，分析上述指标的差异。组间比较采用Mann-Whitney U或χ 2检验，预测院内感染发生的免疫指标采用受试者工作特征（ROC）曲线分析。 结果:无院内感染组104例，院内感染组51例，首次发生院内感染的时间为入PICU后（12±7）d。常见部位为肺部（26例，51.0%）、血流（15例，29.4%）。院内感染组PRISM-Ⅲ显著高于无院内感染组［8（0~31）比4（0~17）分， Z=3 913.00， P<0.01］，使用血管活性药物、有创机械通气所占比例均明显高于无院内感染组［35.3%（18/51）比10.6%（11/104），χ2=13.77， P<0.01；86.3%（44/51）比38.5%（40/104），χ2=31.51， P<0.01］；院内感染组PICU住院时间更长［20（3~94）比7（2~41） d， Z=4 585.50， P<0.01］，病死率更高［29.4%（15/51）比6.7%（7/104），χ2=14.45， P<0.01］；院内感染组白细胞介素（IL）-6、IL-10更高［37.83（2.23~7 209.99）比13.45（0.80~50 580.64）ng/L， Z=3 390.50， P=0.01；10.42（1.11~6 052.21）比4.10（0.16~409.28）ng/L， Z=3 212.00， P=0.03］，CD4 +/CD8 +、CD14 +HLA-DR比例更低［1.16（0.44~4.96）比1.61（0.15~6.37）， Z=1 955.00， P=0.01；0.48（0.08~0.99）比0.67（0.09~0.98）， Z=1 915.50， P<0.01］。PSM后，无院内感染组和院内感染组各46例，院内感染组CD14 +HLA-DR比例明显低于无院内感染组［0.44（0.08~0.99）比0.64（0.09~0.98）， Z=758.00， P=0.02］。CD14 +HLA-DR比例预测院内感染的ROC曲线下面积为0.642，截断值为0.39，95% CI为0.528~0.755。 结论:CD14 +HLA-DR比例水平可能与儿童脓毒症发生院内感染相关。

abstractsObjective:To investigate the immunity markers related to nosocomial infection in children with sepsis.Methods:A retrospective study including 155 cases diagnosed as sepsis from September 2015 to June 2020 in children′s intensive care unit (PICU) of Shanghai Children′s Medical Center was conducted. According to the presence of nosocomial infection occurred in PICU, septic children were divided into two groups: no nosocomial infection and nosocomial infection group. The differences about helper T-cells 1 and 2 cytokines, T cells subgroup absolute count, the proportion of CD14 + human leukocyte antigen DR (CD14 +HLA-DR), the proportion of regulatory T cells, pediatric risk of mortality Ⅲ (PRISM-Ⅲ), the treatment and outcome between the two groups were compared. Through propensity score matching (PSM), the disease severity and treatment of the two groups were matched to analyze the differences between the above indicators. Chi-square test or U test was used for comparison between groups. Receiver operating characteristic (ROC) curve was used to predict the occurrence of nosocomial infection. Results:There were 104 cases in no nosocomial infection group and 51 cases in nosocomial infection group. The first PICU-acquired infections occurred at (12±7) days after PICU admission. The most common PICU-acquired infections were pneumonia (26 cases, 51.0%) and bloodstream infections (15 cases, 29.4%). PRISM-Ⅲ of nosocomial infection group was significantly higher than that in no nosocomial infection group (8 (0-31) vs. 4 (0-17), Z=3 913.00, P<0.01).The proportion of using vasoactive drugs and invasive mechanical ventilation of nosocomial infection group was significantly higher (35.3% (18/51) vs. 10.6% (11/104), χ2=13.77, P<0.01; 86.3% (44/51) vs. 38.5% (40/104), χ2=31.51, P<0.01).The PICU length of stay of nosocomial infection group was significantly longer (20 (3-94) vs.7 (2-41) days, Z=4 585.50, P<0.01). The mortality of the nosocomial infection group was significantly higher than that of the group without nosocomial infection (29.4% (15/51) vs. 6.7% (7/104), χ2=14.45, P<0.01). Interleukin-6 and interleukin-10 of the nosocomial infection group were significantly higher than that in no nosocomial infection group (37.83 (2.23-7 209.99) vs. 13.45 (0.80~50 580.64) ng/L, Z=3 390.50, P=0.01; 10.42 (1.11-6 052.21) vs.4.10 (0.16-409.28) ng/L, Z=3 212.00, P=0.03). CD4 +/CD8 + and the percentage of CD14 +HLA-DR were significantly lower in the nosocomial infection group compared with the no nosocomial infection group (1.16 (0.44-4.96) vs. 1.61 (0.15-6.37), Z=1 955.00, P=0.01; 0.48 (0.08-0.99) vs. 0.67 (0.09-0.98), Z=1 915.50, P<0.01). After PSM, the percentage of CD14 +HLA-DR of nosocomial infection group was significantly lower than that in no nosocomial infection group (0.44 (0.08-0.99) vs. 0.64 (0.09-0.98), Z=758.00, P=0.02). The ROC curve analysis of the percentage of CD14 +HLA-DR in predicting nosocomial infection showed that the area under the curve was 0.642, the cut-off value was 0.39, and the 95% CI was 0.528-0.755. Conclusion:The level of the percentage of CD14 +HLA-DR maybe is related to the occurrence of nosocomial infection in children with sepsis.