Association of COVID-19 inflammation with activation of the C5a–C5aR1 axis
Julien Carvelli, Olivier Demaria, Frédéric Vély, Luciana Batista, Nassima Chouaki Benmansour, Joanna Fares, Sabrina Carpentier, Marie-Laure Thibult, Ariane Morel, Romain Remark, Pascale André, Agnès Represa, Christelle Piperoglou, the Explore COVID-19 IPH group, Pierre Yves Cordier, Erwan Le Dault, Christophe Guervilly, Pierre Simeone, Marc Gainnier, Yannis Morel, Mikael Ebbo, Nicolas Schleinitz, Eric Vivier & the Explore COVID-19 Marseille Immunopole group
Nature (2020)
Abstract
Coronavirus disease 2019 (COVID-19) is a new pandemic disease caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)1. The C5a anaphylatoxin and its receptor C5aR1 (CD88) play a key role in the initiation and maintenance of several inflammatory responses, by recruiting and activating neutrophils and monocytes in the lungs1. We provide a longitudinal analysis of immune responses, including immune cell phenotyping and assessments of the soluble factors present in the blood and broncho-alveolar lavage fluid (BALF) of patients at various stages of COVID-19 severity: paucisymptomatic, pneumonia and acute respiratory distress syndrome (ARDS). We report an increase in soluble C5a levels proportional to COVID-19 severity and high levels of C5aR1 expression in blood and pulmonary myeloid cells, supporting a role for the C5a-C5aR1 axis in the pathophysiology of ARDS. Anti-C5aR1 therapeutic monoclonal antibodies (mAbs) prevented C5a-mediated human myeloid cell recruitment and activation, and inhibited acute lung injury (ALI) in human C5aR1 knockin mice. These results suggest that C5a-C5aR1 axis blockade might be used as a means of limiting myeloid cell infiltration in damaged organs and preventing the excessive lung inflammation and endothelialitis associated with ARDS in COVID-19 patients.
