Induction of soluble platelet activation markers and FXIII deficiency promote COVID-19 severity

Coagulation dysfunction and thromboembolism emerge as strong comorbidity factors in severe COVID-19 patients. However, the underlying pathomechanisms are largely undefined. Here, we sought to identify the potential molecular mechanisms of SARS-CoV-2 mediated coagulopathy and thromboembolism. A broader investigation was conducted including hospitalized COVID-19 patients with (severe cases that required intensive care) or without pneumonia (moderate cases). Phenotypic and molecular characterizations were performed employing basic coagulation tests, flow cytometry-based multiplex assays, and ELISA. The investigations revealed induction of plasma P-selectin and CD40 ligand (sCD40L) in moderate COVID-19 cases which were significantly abolished with the progression of COVID-19 severity. Moreover, a profound reduction in plasma tissue factor pathway inhibitor (TFPI) and FXIII were identified particularly in the severe COVID-19. Further analysis revealed a profound induction of fibrinogen in both moderate and severe patients. Interestingly, an elevated plasminogen activator inhibitor-1 more prominently in moderate, and tissue plasminogen activator (tPA) particularly in severe COVID-19 cases were observed. Particularly, the levels of fibrinogen and tPA directly correlated with the severity of COVID-19. In summary, SARS-CoV-2 infection induces the levels of platelet activation markers soluble P-selectin and sCD40L in hospitalized COVID-19 patients. Furthermore, an attenuated level of TFPI indicates TF pathway activation and, acquired FXIII deficiency likely plays a key role in thrombus instability and promotes thromboembolism in severe cases. The progression of COVID-19 severity could be limited with anti-platelet in combination with recombinantTFPI treatment. Furthermore, thromboembolic events in severe COVID-19 patients could be minimized if treated with recombinantFXIII in combination with LMW heparin.