摘要目的:探索轻症和重症流感肺炎患者外周血单个核细胞（PBMC）环状RNA（circRNA）表达谱差异。方法:选取2018年12月至2019年3月北京朝阳医院感染和临床微生物科收治的轻症和重症流感肺炎住院患者各10例，采用Clariom? D基因芯片检测两组患者PBMC中的circRNA表达谱，以差异倍数（FC）绝对值>2且 P<0.05为标准筛选差异表达circRNA，进行基因本体论（GO）富集分析和京都基因与基因组大百科全书数据库（KEGG）信号通路富集分析。 结果:轻症患者年龄［ M（ P25， P75）］为 62.0（34.5，69.8）岁，其中男性4例；重症患者年龄［ M（ P25， P75）］为50.0（37.0，60.0）岁，均为男性。共筛选出轻、重症患者PBMC差异表达circRNA 137个，其在轻症患者中表达上调和下调的个数分别为101和36个，其中上调表达最显著的是hsa_circ_0091073（FC=160.898， P<0.05），下调表达最显著的是hsa_circ_0092219（FC=-17.630， P<0.05）。GO富集分析显示，与差异表达circRNA相关的GO二级条目共111个（ P<0.05）；与上调表达circRNA相关的包括DNA转录模板、DNA转录模板调控、RNA聚合酶Ⅱ转录调节等；与下调表达circRNA相关的包括中细粒细胞脱颗粒、杀死其他生物的细胞和防御真菌等。KEGG信号通路分析显示，与差异表达circRNA相关的代谢通路共37条（ P<0.05）；与上调表达circRNA相关信号通路包括核转录因子-κB（NF-κB）信号通路、丝裂原活化蛋白激酶（MAPK）信号通路、肿瘤坏死因子（TNF）信号通路等；与下调表达circRNA相关的信号通路包括癌症的转录失调、叶酸碳库和其他类型O-聚糖生物合成等。 结论:轻症与重症流感肺炎患者PBMC中circRNA表达存在明显差异，可能通过多个信号通路在流感肺炎致病机制中发挥作用。

abstractsObjective:To explore the difference in the expression profile of circular RNA in peripheral blood mononuclear cells between patients with mild and severe influenza pneumonia.Methods:From December 2018 to March 2019, 10 inpatients with mild and 10 inpatients with severe influenza pneumonia admitted to the Department of Infection and Clinical Microbiology of Beijing Chaoyang Hospital were included. Clariom? D gene chip was used to explore the circRNA expression profiles of peripheral blood mononuclear cells (PBMC) isolated from the patients. The absolute value of the fold change (FC value)>2 and P<0.05 were used as the criteria to screen the differentially expressed circRNA, and the gene ontology (GO) enrichment analysis and the Kyoto Encyclopedia of Gene and Genome database (Kyoto Encyclopedia of Genes and Genomes, KEGG) signal pathway enrichment analysis were also performed. Results:The age of mild patients [ M ( P25, P75)] was 62.0 (34.5, 69.8) years old, including 4 males; the age of severe patients [ M ( P25, P75)] was 50.0 (37.0, 60.0) years old, all were males. A total of 137 differentially expressed circRNAs in PBMCs of mild and severe patients were screened. The numbers of up-regulated and down-regulated circRNAs in mild patients were 101 and 36, respectively. Among them, hsa_circ_0091073 (FC value=160.898, P<0.05) was the most significantly up-regulated circRNA and hsa_circ_0092219 (FC value =-17.630, P<0.05) was the most significantly down-regulated circRNA. GO enrichment analysis showed that a total of 111 secondary GO items were significantly associated with related differential expression of circRNA ( P<0.05). The GO terms associated with upregulated circRNAs included DNA-templated transcription, regulation of DNA-templated transcription, regulation of transcription from RNA polymerase Ⅱ promoter, etc.; The GO terms associated with downregulated circRNAs included neutrophil degranulation, killing of cells of other organism, defense response to fungus, etc. KEGG signaling pathway analysis showed that there were 37 metabolic pathways related to differentially expressed circRNAs ( P<0.05). Signaling pathways related to up-regulated circRNAs included nuclear factor-κB (NF-κB) signaling pathway, mitogen-activated protein kinase (MAPK) signaling pathway, tumor necrosis factor (TNF) signaling pathway, etc. Signaling pathways related to down-regulation of circRNAs included cancer transcription disorders, folate carbon pool, and other types of O-glycan biosynthesis. Conclusion:The expression of circRNA in PBMC of mild and severe influenza pneumonia patients is significantly different, and it may play a role in the pathogenic mechanism of influenza pneumonia through multiple signal pathways.