Disharmonic Inflammatory Signatures in COVID-19: Augmented Neutrophils' but Impaired Monocytes' and Dendritic Cells' Responsiveness.

COVID-19, caused by SARS-CoV-2 virus, emerged as a pandemic disease posing a severe threat to global health. To date, sporadic studies have demonstrated that innate immune mechanisms, specifically neutrophilia, NETosis, and neutrophil-associated cytokine responses, are involved in COVID-19 pathogenesis; however, our understanding of the exact nature of this aspect of host-pathogen interaction is limited. Here, we present a detailed dissection of the features and functional profiles of neutrophils, dendritic cells, and monocytes in COVID-19. We portray the crucial role of neutrophils as drivers of hyperinflammation associated with COVID-19 disease via the shift towards their immature forms, enhanced degranulation, cytokine production, and augmented interferon responses. We demonstrate the impaired functionality of COVID-19 dendritic cells and monocytes, particularly their low expression of maturation markers, increased PD-L1 levels, and their inability to upregulate phenotype upon stimulation. In summary, our work highlights important data that prompt further research, as therapeutic targeting of neutrophils and their associated products may hold the potential to reduce the severity of COVID-19.

Disharmonic Inflammatory Signatures in COVID-19: Augmented Neutrophils’ but Impaired Monocytes’ and Dendritic Cells’ Responsiveness

COVID-19, caused by SARS-CoV-2 virus, emerged as a pandemic disease posing a severe threat to global health. To date, sporadic studies have demonstrated that innate immune mechanisms, specifically neutrophilia, NETosis, and neutrophil-associated cytokine responses, are involved in COVID-19 pathogenesis;however, our understanding of the exact nature of this aspect of host-pathogen interaction is limited. Here, we present a detailed dissection of the features and functional profiles of neutrophils, dendritic cells, and monocytes in COVID-19. We portray the crucial role of neutrophils as drivers of hyperinflammation associated with COVID-19 disease via the shift towards their immature forms, enhanced degranulation, cytokine production, and augmented interferon responses. We demonstrate the impaired functionality of COVID-19 dendritic cells and monocytes, particularly their low expression of maturation markers, increased PD-L1 levels, and their inability to upregulate phenotype upon stimulation. In summary, our work highlights important data that prompt further research, as therapeutic targeting of neutrophils and their associated products may hold the potential to reduce the severity of COVID-19.

Complex Immunometabolic Profiling Reveals the Activation of Cellular Immunity and Biliary Lesions in Patients with Severe COVID-19.

This study aimed to assess the key laboratory features displayed by coronavirus disease 2019 (COVID-19) inpatients that are associated with mild, moderate, severe, and fatal courses of the disease, and through a longitudinal follow-up, to understand the dynamics of the COVID-19 pathophysiology. All severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-positive patients admitted to the University Hospital in Motol between March and June 2020 were included in this study. A severe course of COVID-19 was associated with an elevation of proinflammatory markers; an efflux of immature granulocytes into peripheral blood; the activation of CD8 T cells, which infiltrated the lungs; transient liver disease. In particular, the elevation of serum gamma-glutamyl transferase (GGT) and histological signs of cholestasis were highly specific for patients with a severe form of the disease. In contrast, patients with a fatal course of COVID-19 failed to upregulate markers of inflammation, showed discoordination of the immune response, and progressed toward acute kidney failure. COVID-19 is a disease with a multi-organ affinity that is characterized by the activation of innate and cellular adaptive immunity. Biliary lesions with an elevation of GGT and the organ infiltration of interleukin 6 (IL-6)-producing cells are the defining characteristics for patients with the fulminant disease.