Neutrophil extracellular traps and thrombogenesis in COVID‑19 patients

COVID‑19 has caused significant morbidity and mortality around the world. Recent reports point toward the “cytokine storm” as core of pathogenesis in SAR‑CoV‑2‑induced acute lung injury, acute respiratory distress syndrome (ARDS), coagulopathy, and multiorgan failure. We have presented clinical data here wherein cytokine levels in COVID‑19 patients do not match typical cytokine storm seen in ARDS. Interestingly, COVID‑19 patients in early disease present with hypoxemia with no significant respiratory dysfunction. In addition, it is reported that hospitalized COVID‑19 patients have a high incidence of thrombotic complications, especially involving the pulmonary vasculature. We hypothesized that core to pathogenesis of COVID‑19 is the dysregulation of neutrophils, which culminates in excessive release of neutrophil extracellular traps (NETs). Recently, an increasing amount of NETs have been seen in sera of severe COVID‑19 patients. We have discussed here mechanisms involved which lead to thrombogenesis and vasculitis because of excessive release of NETs.