Novel coronavirus disease 2019 (COVID-19) is associated with a hypercoagulable state, characterized by abnormal coagulation parameters and by increased incidence of cardiovascular complications. With this study, we aimed to investigate the activation state and the expression of transmembrane proteins in platelets of hospitalized COVID-19 patients. We investigated transmembrane proteins expression with a customized mass cytometry panel of 21 antibodies. Platelets of 8 hospitalized COVID-19 patients not requiring intensive care support and without pre-existing conditions were compared to platelets of healthy controls (11 donors) with and without in vitro stimulation with thrombin receptor-activating peptide (TRAP). Mass cytometry of non-stimulated platelets detected an increased surface expression of activation markers P-Selectin (0.67 vs. 1.87 median signal intensity for controls vs. patients, p = 0.0015) and LAMP-3 (CD63, 0.37 vs. 0.81, p = 0.0004), the GPIIb/IIIa complex (4.58 vs. 5.03, p < 0.0001) and other adhesion molecules involved in platelet activation and platelet–leukocyte interactions. Upon TRAP stimulation, mass cytometry detected a higher expression of P-selectin in COVID-19 samples compared to controls (p < 0.0001). However, we observed a significantly reduced capacity of COVID-19 platelets to increase the expression of activation markers LAMP-3 and P-Selectin upon stimulation with TRAP. We detected a hyperactivated phenotype in platelets during SARS-CoV-2 infection, consisting of highly expressed platelet activation markers, which might contribute to the hypercoagulopathy observed in COVID-19. In addition, several transmembrane proteins were more highly expressed compared to healthy controls. These findings support research projects investigating antithrombotic and antiplatelet treatment regimes in COVID-19 patients, and provide new insights on the phenotypical platelet expression during SARS-CoV-2 infection.

2019 新型冠状病毒病 (COVID-19) 与高凝状态相关，其特点是凝血参数异常和心血管并发症发生率增加。通过这项研究，我们旨在调查住院 COVID-19 患者血小板中跨膜蛋白的激活状态和表达。我们使用包含 21 种抗体的定制质谱流式细胞仪组研究了跨膜蛋白表达。将 8 名不需要重症监护支持且没有既往病史的住院 COVID-19 患者的血小板与接受或不接受凝血酶受体激活肽 (TRAP) 体外刺激的健康对照（11 名捐赠者）的血小板进行比较。未刺激血小板的质量流式细胞仪检测到激活标记物 P-选择蛋白（对照与患者的中值信号强度分别为 0.67 与 1.87，p  = 0.0015）和 LAMP-3（CD63，0.37 与 0.81，p  = 0.0004）、GPIIb/IIIa 复合物（4.58 vs. 5.03，p  < 0.0001）和其他参与血小板活化和血小板-白细胞相互作用的粘附分子。在 TRAP 刺激后，质谱流式分析仪检测到与对照相比，COVID-19 样本中 P-选择素的表达更高 ( p  < 0.0001)。然而，我们观察到，在 TRAP 刺激后，COVID-19 血小板增加激活标记物 LAMP-3 和 P-选择素表达的能力显着降低。我们在 SARS-CoV-2 感染期间检测到血小板过度激活表型，其中包括高表达的血小板激活标记物，这可能导致在 COVID-19 中观察到的高凝血病。此外，与健康对照相比，一些跨膜蛋白的表达更高。这些发现支持了调查 COVID-19 患者抗血栓和抗血小板治疗方案的研究项目，并提供了关于 SARS-CoV-2 感染期间表型血小板表达的新见解。