Highlights Narsoplimab down-modulates SARS-CoV-2-induced activation of the lectin pathway and endothelial cell damage. Narsoplimab can reduce the thrombotic risk of Covid-19 patients. All patients treated with narsoplimab improved and survived without any drug-related adverse events.

COVID-19 infection may lead to an Acute Respiratory Distress Syndrome where severe gas exchange derangements may be associated, at least in the early stages, only with minor pulmonary infiltrates. This suggests that the shunt associated to the gasless lung parenchyma is not sufficient to explain CARDS hypoxemia. We designed an algorithm (VentriQlar), based on the same conceptual grounds described by J.B West in 1969. We set 499 ventilation-perfusion (VA/Q) compartments and, after calculating their blood composition (PO2, PCO2 and pH), we randomly chose 106 combinations of five parameters controlling a bimodal distribution of blood flow. The solutions were accepted if the predicted PaO2 and PaCO2 were within 10% of the patient's values. We assumed that shunt fraction equaled the fraction of non-aerated lung tissue at the CT quantitative analysis. Five critically-ill patients later deceased were studied. The PaO2/FiO2 was 91.1±18.6 mmHg and PaCO2 69.0±16.1 mmHg. Cardiac output was 9.58±0.99 l/min. The fraction of non-aerated tissue was 0.33±0.06. The model showed that a large fraction of the blood flow was likely distributed in regions with very low VA/Q (Qmean=0.06±0.02) and a smaller fraction in regions with moderately high VA/Q. Overall LogSD, Q was 1.66 ± 0.14, suggestive of high VA/Q inequality. Data suggest that shunt alone cannot completely account for the observed hypoxemia and a significant VA/Q inequality must be present in COVID-19. The high cardiac output and the extensive microthrombosis later found in the autopsy further support the hypothesis of a pathological perfusion of non/poorly ventilated lung tissue.

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A large variation in the severity of disease symptoms is one of the key open questions in COVID-19 pandemics. The fact that only a small subset of people infected with SARS-CoV-2 develop severe disease suggests that there have to be some predisposing factors, but biomarkers that reliably predict disease severity have not been found so far. Since overactivation of the immune system is implicated in a severe form of COVID-19 and the IgG glycosylation is known to be involved in the regulation of different immune processes, we evaluated the association of inter-individual variation in IgG N-glycome composition with the severity of COVID-19. The analysis of 166 severe and 167 mild cases from hospitals in Spain, Italy and Portugal revealed statistically significant differences in the composition of the IgG N-glycome. The most notable difference was the decrease in bisecting N-acetylglucosamine (GlcNAc) in severe patients from all three cohorts. IgG galactosylation was also lower in severe cases in all cohorts, but the difference in galactosylation was not statistically significant after correction for multiple testing. To our knowledge, this is the first study exploring IgG N-glycome variability in COVID-19 severity.

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