Acute respiratory failure and a systemic coagulopathy are critical aspects of the morbidity and mortality characterizing infection with severe acute respiratory distress syndrome-associated coronavirus-2 (SARS-CoV-2), the etiologic agent of Coronavirus disease 2019 (COVID-19). We examined skin and lung tissues from 5 patients with severe COVID-19 characterized by respiratory failure (n=5) and purpuric skin rash (n=3). The pattern of COVID-19 pneumonitis was predominantly a pauci-inflammatory septal capillary injury with significant septal capillary mural and luminal fibrin deposition and permeation of the inter-alveolar septa by neutrophils. No viral cytopathic changes were observed and the diffuse alveolar damage (DAD) with hyaline membranes, inflammation, and type II pneumocyte hyperplasia, hallmarks of classic ARDS, were not prominent. These pulmonary findings were accompanied by significant deposits of terminal complement components C5b-9 (membrane attack complex), C4d, and mannose binding lectin (MBL)-associated serine protease (MASP)2, in the microvasculature, consistent with sustained, systemic activation of the alternative and lectin-based complement pathways. The purpuric skin lesions similarly showed a pauci-inflammatory thrombogenic vasculopathy, with deposition of C5b-9 and C4d in both grossly involved and normally-appearing skin. In addition, there was co-localization of COVID-19 spike glycoproteins with C4d and C5b-9 in the inter-alveolar septa and the cutaneous microvasculature of two cases examined. In conclusion, at least a subset of sustained, severe COVID-19 may define a type of catastrophic microvascular injury syndrome mediated by activation of complement pathways and an associated procoagulant state. It provides a foundation for further exploration of the pathophysiologic importance of complement in COVID-19, and could suggest targets for specific intervention.
Translational research : the journal of laboratory and clinical medicine. 2020 Apr 15 [Epub ahead of print]
Cynthia Magro, J Justin Mulvey, David Berlin, Gerard Nuovo, Steven Salvatore, Joanna Harp, Amelia Baxter-Stoltzfus, Jeffrey Laurence
Department of Pathology and Laboratory Medicine, Weill Cornell Medicine., Department of Laboratory Medicine, Memorial Sloan-Kettering Cancer Center., Department of Medicine, Division of Pulmonary and Critical Care Medicine, Weill Cornell Medicine, New York, NY, USA., The Ohio State University Comprehensive Cancer Center, Columbus Ohio and Discovery Life Sciences, Powell, Ohio., Department of Dermatology, Weill Cornell Medicine., Department of Medicine, Division of Hematology and Medical Oncology, Weill Cornell Medicine, New York, NY, USA. Electronic address: .