ABSTRACT
Background: Severe progression of coronavirus disease 2019 (COVID‑19) causes respiratory failure and critical illness. Recently, these pathologies have been associated with necroptosis, a receptor‑interacting serine/threonine‑protein kinase 3 (RIPK3) dependent regulated form of inflammatory cell death. Investigations of indicator necroptosis proteins like RIPK3, mixed lineage kinase domain‑like pseudokinase (MLKL), receptor‑interacting serine/threonine‑protein kinases 1 (RIPK1), and high‑mobility group box 1 (HMGB1) in clinical COVID‑19 manifestations are lacking. Methods: : A prospective prolonged cohort study including 46 intensive care unit (ICU) patients classified with moderate and severe COVID‑19 was conducted with daily measured plasma levels of indicator necroptosis proteins like RIPK3, MLKL, RIPK1, and HMGB1 by enzyme‑linked immunosorbent assay (ELISA). On this basis, a multiple logistic (regression) classification for the prediction of severe COVID‑19 progression was performed. Results: : We found significantly elevated RIPK3, MLKL, HMGB1, and RIPK1 levels in COVID‑19 patients admitted to the ICU compared to healthy controls throughout the ongoing disease, indicating necroptotic processes. Above all, with combined measurements of RIPK3 and HMGB1 plasma levels, we were able to time‑independently predict COVID‑19 severity with 84% accuracy, 90% sensitivity, and 76% specificity. Conclusion: We suggest that HMGB1 and RIPK3 are potential biomarkers to identify high‑risk COVID‑19 patients and developed a classifier for COVID‑19 severity.
Subject(s)
Coronavirus Infections , COVID-19 , Respiratory InsufficiencyABSTRACT
Due to the highly variable clinical phenotype of Coronavirus disease 2019 (COVID-19), deepening the host genetic contribution to severe COVID-19 may further improve our understanding about underlying disease mechanisms. Here, we describe an extended GWAS meta-analysis of 3,260 COVID-19 patients with respiratory failure and 12,483 population controls from Italy, Spain, Norway and Germany, as well as hypothesis-driven targeted analysis of the human leukocyte antigen (HLA) region and chromosome Y haplotypes. We include detailed stratified analyses based on age, sex and disease severity. In addition to already established risk loci, our data identify and replicate two genome-wide significant loci at 17q21.31 and 19q13.33 associated with severe COVID-19 with respiratory failure. These associations implicate a highly pleiotropic ~0.9-Mb 17q21.31 inversion polymorphism, which affects lung function and immune and blood cell counts, and the NAPSA gene, involved in lung surfactant protein production, in COVID-19 pathogenesis.
Subject(s)
COVID-19 , Respiratory InsufficiencyABSTRACT
Coronavirus disease 2019 (COVID-19) displays high clinical variability but the parameters that determine disease severity are still unclear. Pre-existing T cell memory has been hypothesized as a protective mechanism but conclusive evidence is lacking. Here we demonstrate that all unexposed individuals harbor SARS-CoV-2-specific memory T cells with marginal cross-reactivity to common cold corona and other unrelated viruses. They display low functional avidity and broad protein target specificities and their frequencies correlate with the overall size of the CD4+ memory compartment reflecting the immunological age of an individual. COVID-19 patients have strongly increased SARS-CoV-2-specific inflammatory T cell responses that are correlated with severity. Strikingly however, patients with severe COVID-19 displayed lower TCR functional avidity and less clonal expansion. Our data suggest that a low avidity pre-existing T cell memory negatively impacts on the T cell response quality against neoantigens such as SARS-CoV-2, which may predispose to develop inappropriate immune reactions especially in the elderly. We propose the immunological age as an independent risk factor to develop severe COVID-19.