Project description:Since the start of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, a disease that has become one of the world's greatest global health challenges, the role of the immune system has been at the forefront of scientific studies. The pathophysiology of coronavirus disease 2019 (COVID-19) is complex, which is evident in those at higher risk for poor outcome. Multiple systems contribute to thrombosis and inflammation seen in COVID-19 patients, including neutrophil and platelet activation, and endothelial dysfunction. Understanding how the immune system functions in different patient cohorts (particularly given recent emerging events with the Oxford/AstraZeneca vaccine) is vital to understanding the pathophysiology of this devastating disease and for the subsequent development of novel therapeutic targets and to facilitate possible drug repurposing strategies that could benefit society on a global scale. LINKED ARTICLES: This article is part of a themed issue on The second wave: are we any closer to efficacious pharmacotherapy for COVID 19? (BJP 75th Anniversary). To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.10/issuetoc.
Project description:The pathophysiology of COVID-19-associated thrombosis seems to be multifactorial. We hypothesized that COVID-19 is accompanied by procoagulant platelets with subsequent alteration of the coagulation system. We investigated depolarization of mitochondrial inner transmembrane potential (ΔΨm), cytosolic calcium (Ca2+) concentration, and phosphatidylserine (PS) externalization. Platelets from COVID-19 patients in the intensive care unit (ICU; n = 21) showed higher ΔΨm depolarization, cytosolic Ca2+, and PS externalization compared with healthy controls (n = 18) and non-ICU COVID-19 patients (n = 4). Moreover, significant higher cytosolic Ca2+ and PS were observed compared with a septic ICU control group (ICU control; n = 5). In the ICU control group, cytosolic Ca2+ and PS externalization were comparable with healthy controls, with an increase in ΔΨm depolarization. Sera from COVID-19 patients in the ICU induced a significant increase in apoptosis markers (ΔΨm depolarization, cytosolic Ca2+, and PS externalization) compared with healthy volunteers and septic ICU controls. Interestingly, immunoglobulin G fractions from COVID-19 patients induced an Fcγ receptor IIA-dependent platelet apoptosis (ΔΨm depolarization, cytosolic Ca2+, and PS externalization). Enhanced PS externalization in platelets from COVID-19 patients in the ICU was associated with increased sequential organ failure assessment score (r = 0.5635) and D-dimer (r = 0.4473). Most importantly, patients with thrombosis had significantly higher PS externalization compared with those without. The strong correlations between markers for apoptosic and procoagulant platelets and D-dimer levels, as well as the incidence of thrombosis, may indicate that antibody-mediated procoagulant platelets potentially contributes to sustained increased thromboembolic risk in ICU COVID-19 patients.
Project description:We perform shotgun transcriptome sequencing of human RNA obtained from nasopharyngeal swabs of patients with COVID-19, and identify a molecular signature associated with disease severity
Project description:Early in the COVID-19 pandemic, type 2 diabetes (T2D) was marked as a risk-factor for severe disease. Inflammation is central to the aetiology of both conditions where immune responses influence disease course. Identifying at-risk groups through immuno-inflammatory signatures can direct personalised care and help develop potential targets for precision therapy. This observational study characterised immunophenotypic variation associated with COVID-19 severity in T2D. Broad-spectrum immunophenotyping quantified 15 leukocyte populations in circulation from a cohort of 45 hospitalised COVID-19 patients with and without T2D. Lymphocytopenia, of CD8+ lymphocytes, was associated with severe COVID-19 and intensive care admission in non-diabetic and T2D patients. A morphological anomaly of increased monocyte size and monocytopenia of classical monocytes were specifically associated with severe COVID-19 in patients with T2D requiring intensive care. Over-expression of inflammatory markers reminiscent of the type-1 interferon pathway underlaid the immunophenotype associated with T2D. These changes may contribute to severity of COVID-19 in T2D. These findings show characteristics of severe COVID-19 in T2D as well as provide evidence that type-1 interferons may be actionable targets for future studies.