Complement associated microvascular injury and thrombosis in the pathogenesis of severe COVID-19 infection: A report of five cases.

TitleComplement associated microvascular injury and thrombosis in the pathogenesis of severe COVID-19 infection: A report of five cases.
Publication TypeJournal Article
Year of Publication2020
AuthorsMagro C, J Mulvey J, Berlin D, Nuovo G, Salvatore S, Harp J, Baxter-Stoltzfus A, Laurence J
JournalTransl Res
Volume220
Pagination1-13
Date Published2020 06
ISSN1878-1810
KeywordsAdult, Aged, Betacoronavirus, Complement Activation, Complement System Proteins, Coronavirus Infections, COVID-19, Female, Humans, Male, Microvessels, Middle Aged, Pandemics, Pneumonia, Viral, Purpura, Respiratory Insufficiency, SARS-CoV-2, Thrombosis
Abstract

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, 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). COVID-19 pneumonitis was predominantly a pauci-inflammatory septal capillary injury with significant septal capillary mural and luminal fibrin deposition and permeation of the interalveolar 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 acute respiratory distress syndrome, 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 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 interalveolar septa and the cutaneous microvasculature of 2 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.

DOI10.1016/j.trsl.2020.04.007
Alternate JournalTransl Res
PubMed ID32299776
PubMed Central IDPMC7158248
Grant ListP30 CA008748 / CA / NCI NIH HHS / United States
Related Faculty: 
Cynthia M. Magro, M.D. Steven P. Salvatore, M.D.

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