COVID-19 virus has currently caused major outbreaks worldwide. ACE2 is a major cellular-entry receptor for the COVID-19 virus. Although ACE2 is known to be expressed in many organs, whether it is expressed by the conjunctival tissue is largely unknown. Human conjunctival tissues from 68 subjects were obtained, which included 10 subjects with conjunctival nevi, 20 subjects with conjunctivitis, 9 subjects with conjunctival papilloma, 16 subjects with conjunctival cyst, 7 subjects with conjunctival polyps, and 6 ocular traumas as normal subjects. Expression of ACE2 was evaluated by immunohistochemistry, immunofluorescence, reverse transcriptase-quantitative polymerase chain reaction, and western blot assay. We observed the expression of ACE2 by conjunctival tissues, expecially in conjunctival epithelial cells. ACE2 was significantly (p<0.001) overexpressed in conjunctival cells obtained from subjects with conjunctivitis, conjunctival nevi, conjunctival papilloma, conjunctival cyst, and conjunctival polyps epithelial cells when compared to that in conjunctival epithelial cells obtained from control subjects. Collectively, clinical features of reported COVID-19 patients combined with our results indicate that COVID-19 is likely to be transmitted through the conjunctiva.

中文翻译：

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SARS-CoV-2受体ACE2在人结膜组织中表达，尤其是在患病的结膜组织中表达

目前，COVID-19病毒已在全球范围内引起了大规模的爆发。ACE2是COVID-19病毒的主要细胞进入受体。尽管已知ACE2在许多器官中都有表达，但很大程度上尚不清楚它是否由结膜组织表达。获得了来自68名受试者的人结膜组织，其中包括10名结膜痣受试者，20名结膜炎受试者，9名结膜乳头瘤受试者，16名结膜囊肿受试者，7名结膜息肉受试者和6例眼外伤。通过免疫组织化学，免疫荧光，逆转录酶定量聚合酶链反应和蛋白质印迹试验评估ACE2的表达。我们观察到结膜组织，尤其是结膜上皮细胞中ACE2的表达。ACE2显着（p <0。001）与从对照对象获得的结膜上皮细胞相比，在结膜炎，结膜痣，结膜乳头瘤，结膜囊肿和结膜息肉上皮细胞中获得的结膜细胞中过表达。总的来说，已报告的COVID-19患者的临床特征与我们的结果相结合表明，COVID-19可能通过结膜传播。