Objective To search for potential prognostic markers for severe community-acquired pneumonia（SCAP）using non-targeted metabolomics. Methods Testing plasma samples from 30 healthy people and 68 SCAP patients (all collected from January 2015 to June 2019 at Peking Union Medical College Hospital) by liquid chromatography mass spectrometry(LC-MS ).According to clinical prognosis，patients were divided into survive group (n=49)and non-survive group(n=19).OPLS-DA(multivariate statistical analysis)and Kruskal Wallis Test (single variable statistical analysis) were used to identify differential metabolites. Correlation analysis of clinical indicators and prognostic analysis were also used for differential metabolites. Results Totally 3463 metabolites were detected in healthy people and SCAP patients by LC-MS. Among them, 126 metabolites were screened out by OPLS-DA andKruskal Wallis Test analysis methods. Prognostic analysis showed that the quantity of 5-hydroxytryptamine(5-HT) was significantly different between survive group and non-survive group(P<0.05，AUC>0.75).Correlation analysis of clinical indicators showed that 5-HT was positively correlated with oxygenation index (OI) and negatively cor-related with acute physiology and chronic health evaluation(APACHE II)score. Conclusions The 5-HT as a potential prognostic marker for SCAP，may predict the prognosis of SCAP patients.

[摘 要] 目的：采用生物信息学方法分析E3泛素连接酶（HECW2）在胃腺癌组织中的表达及其临床意义，为寻找胃腺癌诊断和预后生物标志物提供新的线索。方法：用R语言分析HECW2在泛癌中的表达及其与泛癌预后的关系。借助UCSC Xena、HPA、Kaplan-Meier Plotter等数据库分析HECW2在胃腺癌组织中的表达及其与临床病理特征之间的关系。采用WB法检测中国人胃腺癌组织及其癌旁组织中HECW2蛋白水平以验证数据库中的分析结果。借助TIMER和Cibersort数据库分析HECW2与胃腺癌免疫浸润的关系。通过LinkedOmics数据库对胃腺癌中HECW2进行GO功能分析和KEGG信号通路富集分析及相关性基因分析。结果：生物信息学分析结果表明，33种不同类型肿瘤中，包括胃腺癌在内的12种肿瘤中HECW2呈显著高表达（均P<0.05），WB法结果显示，中国人胃腺癌组织中HECW2也呈显著高表达（P<0.05）。HECW2表达水平越高，胃腺癌患者OS越短，包括CD4+ T细胞、巨噬细胞、中性粒细胞和树突状细胞在内的免疫细胞浸润丰度越高（均P˂0.01）。此外，HECW2相关信号通路主要富集于细胞外基质受体相互作用、黏着斑、细胞黏附和氧化磷酸化等生理病理过程（均P˂0.01）。结论：HECW2在胃腺癌组织中呈显著高表达且其与胃腺癌预后不良和免疫细胞浸润密切相关，有成为胃腺癌预后标志物和治疗靶点的潜力。