Project description:To trace immune responses in COVID-19 patients with severity, we performed in-depth, longitudinal single-cell multiomics involving T-cell receptor (TCR)/B-cell receptor (BCR) sequencing, feature barcoded antibody (Ab) panel detection (i.e., cellular indexing of transcriptomes and epitopes by sequencing, CITE-seq) followed by RNA sequencing in a single-cell resolution.
Project description:Mechanisms of neutrophil involvement in severe COVID-19 remain incompletely understood. Here we collect longitudinal blood samples from 306 hospitalized COVID-19+ patients and 86 controls, and perform bulk RNA-sequencing of enriched neutrophils, plasma proteomics, and high-throughput antibody profiling to investigate relationships between neutrophil states and disease severity. We identify dynamic switches between 6 distinct neutrophil subtypes. At days 3 and 7 post-hospitalization, patients with severe disease display a granulocytic myeloid-derived suppressor cell-like gene expression signature, while patients with resolving disease show a neutrophil progenitor-like signature. Humoral responses are identified as potential drivers of neutrophil effector functions, with elevated SARS-CoV-2-specific IgG1-to-IgA1 ratios in plasma of severe patients who survived. In vitro experiments confirm that while patient-derived IgG antibodies induce phagocytosis in healthy donor neutrophils, IgA antibodies predominantly induce neutrophil cell death. Overall, our study demonstrates a dysregulated myelopoietic response in severe COVID-19 and a potential role for IgA-dominant responses contributing to mortality.
Project description:Infection with SARS-CoV-2 has highly variable clinical manifestations, ranging from asymptomatic infection through to life-threatening disease. Host whole blood transcriptomics can offer unique insights into the biological processes underpinning infection and disease, as well as severity. We performed whole blood RNA-Sequencing of individuals with varying degrees of COVID-19 severity. We used differential expression analysis and pathway enrichment analysis to explore how the blood transcriptome differs between individuals with mild, moderate, and severe COVID-19, performing pairwise comparisons between groups.
Project description:Genome-wide DNA methylation analysis of COVID-19 severity using the Illumina HumanMethylationEPIC microarray platform to analyze over 850,000 methylation sites, comparing COVID-19 patients with patients presenting with respiratory symptoms, but negative for COVID-19, using whole blood tissue.
Project description:Post-acute sequelae of COVID-19 (PASC) represent an emerging global crisis. However, quantifiable risk-factors for PASC and their biological associations are poorly resolved. We executed a deep multi-omic, longitudinal investigation of 309 COVID-19 patients from initial diagnosis to convalescence (2-3 months later), integrated with clinical data, and patient-reported symptoms. We resolved four PASC-anticipating risk factors at the time of initial COVID-19 diagnosis: type 2 diabetes, SARS-CoV-2 RNAemia, Epstein-Barr virus viremia, and specific autoantibodies. In patients with gastrointestinal PASC, SARS-CoV-2-specific and CMV-specific CD8+ T cells exhibited unique dynamics during recovery from COVID-19. Analysis of symptom-associated immunological signatures revealed coordinated immunity polarization into four endotypes exhibiting divergent acute severity and PASC. We find that immunological associations between PASC factors diminish over time leading to distinct convalescent immune states. Detectability of most PASC factors at COVID-19 diagnosis emphasizes the importance of early disease measurements for understanding emergent chronic conditions and suggests PASC treatment strategies.
Project description:COVID-19 induces profound B-cell dysregulation, notably a marked expansion of plasmablasts (PB), whose functional role remains unclear. This study aimed to characterize PB dynamics and functions in COVID-19 and their association with disease severity. We performed longitudinal immune profiling in a prospective cohort of 50 patients with COVID-19 (cohort 1), including flow cytometry-based B-cell immunophenotyping and multiplex cytokine analysis at days 1, 7, 14, and 30. A second retrospective cohort of 282 corticosteroid-naïve patients (cohort 2) was used to validate PB dynamics, model PB trajectories, and perform transcriptomic profiling of sorted PB. PB expansion occurred early in COVID-19 and was positively correlated with maximal disease severity (r=0.53, p<0.0001). Two distinct PB expansion trajectories were identified: one rapidly resolving, and one persistent and amplified, the latter being associated with higher severity scores and 30-day mortality (31% vs. 5%, p<0.001). In cohort 1, BAFF levels at day 7 correlated positively with both PB proportion (r=0.59, p=0.002) and maximal disease severity (r=0.74, p<0.001). Transcriptomic profiling of PB in cohort 2 revealed severity-specific signatures: in severe cases, early PB upregulated genes related to purine metabolism and CD39 expression, suggesting a pro-inflammatory role. In non-severe cases, PB expressed interferon-related and CIITA-mediated MHC-II programs, indicative of antiviral function. PB display dual functional profiles in COVID-19, acting either as regulators of antiviral immunity or as amplifiers of inflammation in severe disease. These findings support exploring therapeutic strategies targeting the BAFF-PB axis in severe COVID-19.
Project description:The causative organism, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), exhibits a wide spectrum of clinical manifestations in disease-ridden patients. Differences in the severity of COVID-19 ranges from asymptomatic infections and mild cases to the severe form, leading to acute respiratory distress syndrome (ARDS) and multiorgan failure with poor survival. MiRNAs can regulate various cellular processes, including proliferation, apoptosis, and differentiation, by binding to the 3′UTR of target mRNAs inducing their degradation, thus serving a fundamental role in post-transcriptional repression. Alterations of miRNA levels in the blood have been described in multiple inflammatory and infectious diseases, including SARS-related coronaviruses. We used microarrays to delineate the miRNAs and snoRNAs signature in the peripheral blood of severe COVID-19 cases (n=9), as compared to mild (n=10) and asymptomatic (n=10) patients, and identified differentially expressed transcripts in severe versus asymptomatic, and others in severe versus mild COVID-19 cases. A cohort of 29 male age-matched patients were selected. All patients were previously diagnosed with COVID-19 using TaqPath COVID-19 Combo Kit (Thermo Fisher Scientific, Waltham, Massachusetts), or Cobas SARS-CoV-2 Test (Roche Diagnostics, Rotkreuz, Switzerland), with a CT value < 30. Additional criterion for selection was age between 35 and 75 years. Participants were grouped into severe, mild and asymptomatic. Classifying severe cases was based on requirement of high-flow oxygen support and ICU admission (n=9). Whereas mild patients were identified based on symptoms and positive radiographic findings with pulmonary involvement (n=10). Patients with no clinical presentation were labelled as asymptomatic cases (n=10).
Project description:The 3p21.31 locus, which locus contains a chemokine receptor (CKR) cluster, is the most robust genomic region associated with COVID-19 severity. We tested expression quantitative trait loci (eQTL) targeting the 3p21.31 CKR cluster linked to COVID-19 hospitalization in Europeans from the COVID-19 HGI meta-analysis. Among these, CCRL2, a key regulator of neutrophil trafficking, was targeted by neutrophil-restricted eQTLs. We confirmed these eQTLs in an Italian COVID-19 cohort. Haplotype analysis revealed a link between an increased CCRL2 expression and COVID-19 severity and hospitalization. By the exposure of neutrophils to a TLR8 ligand, reflecting a viral infection, we revealed specific chromatin domains within the 3p21.31 locus exclusive to neutrophils. In addition, the identified variants mapped within these regions altered the binding motif of neutrophils expressed transcription factors. These results support that CCRL2 eQTL variants contribute to the risk of severe COVID-19 by selectively affecting neutrophil’s function