key: cord-1007895-z3vstutp authors: Inoue, Ken-ichiro; Sagawa, Tomoya; Takano, Hirohisa title: COVID-19 and Coagulopathy date: 2021-03-26 journal: American journal of respiratory cell and molecular biology DOI: 10.1165/rcmb.2020-0588le sha: 8dbef46a29cae6f8fb4491f60b989c74a7a1729a doc_id: 1007895 cord_uid: z3vstutp nan To the Editor: We read with interest the recent review article by Rodriguez and colleagues regarding endothelial dysfunction and consequent thrombotic complication in patients with coronavirus disease (COVID-19) (1). Here, we would like to add a point. We will provide supplementary explanation on a molecular group (e.g., IL-1, IL-6, and TNF-a) that has been implicated in coagulation activation in the paper. We wish to explain the complex role of IL-6 in coagulopathy accompanied by severe inflammation. Using IL-6 knockout (IL-6 2/2 ) mice, we have previously demonstrated that IL-6 serves as a protector in coagulatory disturbance and thrombocytopenia during devastating systemic inflammation induced by intraperitoneal administration of bacterial endotoxins (LPS) (2) , which was evidenced by prothrombin time and activated partial thromboplastin time. Furthermore, we have confirmed that in the presence of LPS, a 2 -plasmin inhibitor activity was significantly lower in IL-6 2/2 mice than in wild-type mice, indicating that IL-6 can partially inhibit LPS-provocated fibrinolysis by enhancing a 2 -plasmin inhibitor activity (3) . Interestingly, fibrin degradation product was significantly lower in the IL-6 2/2 mice administered with LPS than in the wild-type mice, whereas D-dimer was comparable in both groups (unpublished observation; these complicated results require future research for further clarification). Regardless, IL-6 may not be introduced in the same way as other proinflammatory cytokines, such as IL-1 and TNF-a, in coagulatory disturbance with persistent inflammation. Author disclosures are available with the text of this letter at www. atsjournals.org. Conditionally reprogrammed cells represent a stem-like state of adult epithelial cells ROCK inhibitor and feeder cells induce the conditional reprogramming of epithelial cells Efficient RNP-directed human gene targeting reveals SPDEF is required for IL-13-induced mucostasis Highly efficient genome editing in primary human bronchial epithelial cells differentiated at air-liquid interface Critical supply shortages -the need for ventilators and personal protective equipment during the covid-19 pandemic Recycle those cell culture inserts Human nasal and tracheo-bronchial respiratory epithelial cell culture IL-1b dominates the promucin secretory cytokine profile in cystic fibrosis Culture of murine nasal epithelia: model for cystic fibrosis Pulmonary endothelial dysfunction and thrombotic complications in patients with COVID-19 Protective role of interleukin-6 in coagulatory and hemostatic disturbance induced by lipopolysaccharide in mice Role of interleukin-6 in fibrinolytic changes induced by lipopolysaccharide in mice Copyright © 2021 by the American Thoracic Society Reply to: COVID-19 and Coagulopathy From the Authors: We read the letter from Dr. Inoue and colleagues with interest and recognize the importance of pointing out that IL-6