The coronavirus disease-2019 (COVID-19) caused by the SARS-CoV-2 virus may vary from asymptomatic to severe infection with multi-organ failure and death. Increased levels of circulating complement biomarkers have been implicated in COVID-19-related hyperinflammation and coagulopathy. We characterized systemic complement activation at a cellular level in 49-patients with COVID-19. We found increases of the classical complement sentinel C1q and the downstream C3 component on circulating blood monocytes from COVID-19 patients when compared to healthy controls (HCs). Interestingly, the cell surface-bound complement inhibitor CD55 was also upregulated in COVID-19 patient monocytes in comparison with HC cells. Monocyte membrane-bound C1q, C3 and CD55 levels were associated with plasma inflammatory markers such as CRP and serum amyloid A during acute infection. Membrane-bounds C1q and C3 remained elevated even after a short recovery period. These results highlight systemic monocyte-associated complement activation over a broad range of COVID-19 disease severities, with a compensatory upregulation of CD55. Further evaluation of complement and its interaction with myeloid cells at the membrane level could improve understanding of its role in COVID-19 pathogenesis.
【저자키워드】 COVID-19, Monocytes, Inflammation, complement, surface expression, 【초록키워드】 coronavirus disease, Monocytes, Severe infection, coronavirus, Biomarker, myeloid cells, CRP, SARS-CoV-2 virus, complement, monocyte, COVID-19 disease, Coagulopathy, Complement activation, COVID-19 pathogenesis, Asymptomatic, cells, acute infection, hyperinflammation, death, membrane, plasma, Inflammatory marker, Complement inhibitor, inhibitor, COVID-19 patients, cellular, Interaction, COVID-19 patient, the cell, amyloid A, Activation, cell surface, healthy control, Increases, serum amyloid, multi-organ failure, upregulation, healthy controls, circulating, myeloid cell, downstream, membrane-bound, CD55, Cell, highlight, IMPROVE, classical, caused, remained, elevated, characterized, increase, upregulated, implicated, Increased, blood monocyte, C1q, HCs, the SARS-CoV-2 virus, with COVID-19, 【제목키워드】 Monocytes, component,