Abstract
Cytokine release syndrome (CRS) has been increasingly recognized in various conditions including the coronavirus disease 2019 (COVID-19). It is not only associated with systemic inflammatory symptoms, but also hematological complications such as coagulopathy. CRS can affect various components of the coagulation pathway, including the endothelial cells, platelets, coagulation cascade, and fibrinolytic system. Different causes of CRS, such as primary hemophagocytic lymphohistocytosis (HLH), chimeric antigen receptor (CAR) T-cell therapy, and COVID-19, have different cytokine profiles and coagulopathy presentations, with microvascular thrombosis surfacing as a common pathology. HLH shares many features with severe CRS, and is characterized by severe consumptive coagulopathy, frequent disseminated intravascular coagulation and an increased bleeding risk. CAR T-cell therapy is characterized by frequent and mild consumptive coagulopathy, as well as an increased risk of thrombosis. While consumptive coagulopathy is rare in COVID-19, it is associated with an increased thrombotic risk. The differences can be explained by the severity of CRS and underlying conditions associated with coagulopathy. Various treatments, including cytokine inhibitors, plasma exchange, Janus kinases inhibitors, complement blockade, and corticosteroids are being studied to mitigate CRS-related coagulopathy.