本研究旨在进一步探讨结核性胸膜炎患者胸水和血清外泌体中miRNA的差异性表达情况，为寻找能够诊断与鉴别诊断结核性胸膜炎的潜在生物学标志物提供依据。收集20例肺结核合并结核性胸膜炎患者(试验组)、20例肺炎合并炎性胸水患者(对照组2)的胸水和血清样本，以及20例健康体检者(对照组1)的血清样本，分离外泌体后提取总RNA，采用实时荧光定量聚合酶链反应(polymerase chain reaction，PCR)分析比较各组外泌体miRNA的相对表达量。结果显示，对照组2血清外泌体miRNA的表达水平均高于对照组1，其中升高明显的有let-7a-5p、let-7c-5p、let-7i-5p和miRNA-126-3p，而试验组血清外泌体中miRNA的表达水平升高得更明显，其中升高最为明显的有let-7a-5p、let-7d-5p、let-7e-5p、miRNA-126-3p、let-7g-5p和let-7c-5p，差异均有统计学意义(P＜0.05)；同时试验组胸水外泌体中miRNA水平普遍高于对照组2胸水外泌体水平，升高较明显的有let-7f-5p、let-7g-5p、let-7d-3p，差异也有统计学意义(P＜0.05)。本研究显示，结核性胸膜炎患者胸水和血清外泌体中miRNA与一般性肺炎合并胸水患者的胸水和血清中外泌体miRNA存在差异性表达，尤其hsm-let-7家族成员可能可以作为结核性胸水与一般炎性胸水的鉴别诊断指标。

The purpose of this study is to investigate the differential expression of miRNA in pleural fluid and serum exosomes from patients with tuberculous pleurisy, which is to provide a basis for diagnosis and differential diagnosis of tuberculous pleurisy. Serum and pleural fluid specimens from 20 patients who had tuberculous pleurisy (experiment group) and 20 patients who had pneumonia with inflammatory pleural effusion (control group 2) were collected. 20 healthy persons’ serum (control group 1) were collected, too. The exosomes were separated and total RNA were extracted for expression level analysis of miRNA with real-time quantitative polymerase chain reaction (PCR) technology. The results showed that compared with control group 1, the level of miRNA expression in serum exosomes from control group 2 was increased in different degree, among them the let-7a-5p, let-7c-5p, let-7i-5p and miRNA-126-3p increased significantly. The expression level of miRNA in the serum exosomes from experimental group was higher than that of control group 2, especially let-7a-5p, let-7d-5p, let-7e-5p, miRNA-126-3p, let-7g-5p and let-7c-5p (P<0.05). Compared with control group 2, the expression levels of miRNA in pleural effusion exosomes from the experimental group were higher, and let-7f-5p, let-7g-5p, let-7d-3p were obviously higher than those in the control group 2. The expressions of miRNA in pleural effusion and serum exosomes were also significantly different in the experimental group. So it was concluded that the expressions of miRNA in pleural fluid and serum exosomes from patients with tuberculous pleurisy were different from general pneumonia with pleural effusion. The hsm-let-7 family members might be used as a good differential diagnostic index between tuberculous pleural effusion and common inflammatory pleural effusion.