Complement lectin pathway activation is associated with COVID-19 disease severity, independent of MBL2 genotype subgroups
Lisa Hurler, Ágnes Szilágyi, Federica Mescia, Laura Bergamaschi, Blanka Mező, György Sinkovits, Marienn Réti, Veronika Müller, Zsolt Iványi, János Gál, László Gopcsa, Péter Reményi, Beáta Szathmáry, Botond Lakatos, János Szlávik, Ilona Bobek, Zita Z. Prohászka, Zita Z. Prohászka, Zsolt Förhécz, Dorottya Csuka, Erika Kajdácsi, László Cervenak, Petra Kiszel, Tamás Masszi, István Vályi‐Nagy, Reinhard Würzner, Paul Lyons, Erik J. M. Toonen, Zoltán Prohászka, Zoltán Prohászka
Abstract
Introduction: While complement is a contributor to disease severity in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, all three complement pathways might be activated by the virus. Lectin pathway activation occurs through different pattern recognition molecules, including mannan binding lectin (MBL), a protein shown to interact with SARS-CoV-2 proteins. However, the exact role of lectin pathway activation and its key pattern recognition molecule MBL in COVID-19 is still not fully understood. Methods: We therefore investigated activation of the lectin pathway in two independent cohorts of SARS-CoV-2 infected patients, while also analysing MBL protein levels and potential effects of the six major single nucleotide polymorphisms (SNPs) found in the MBL2 gene on COVID-19 severity and outcome. Results: We show that the lectin pathway is activated in acute COVID-19, indicated by the correlation between complement activation product levels of the MASP-1/C1-INH complex (p=0.0011) and C4d (p<0.0001) and COVID-19 severity. Despite this, genetic variations in MBL2 are not associated with susceptibility to SARS-CoV-2 infection or disease outcomes such as mortality and the development of Long COVID. Conclusion: In conclusion, activation of the MBL-LP only plays a minor role in COVID-19 pathogenesis, since no clinically meaningful, consistent associations with disease outcomes were noted.