Interferon-inducible mediators are associated with sars-cov-2 and related severity amongst critically ill patients suspected of covid-19

RATIONALE: Several studies have identified host immune signatures that are associated with COVID-19. However, it is unclear whether these immune signatures are specific to COVID-19 or are merely reflective of illness severity. In vitro studies have demonstrated that human T-cell responses to SARS-CoV-2-specific antigens are mediated through interferon-gamma (IFN-γ). Methods: We prospectively enrolled a multi-site cohort of patients admitted to the ICU under suspicion for COVID-19 who were then determined to be SARS-CoV-2-positive (n = 82) or-negative (n = 97) by RT-PCR. We measured multiple molecular and cellular immune profiles from blood and endotracheal aspirates (ETAs) collected on ICU admission. Our primary analysis tested for associations between IFN-γ and interferon-inducible mediators (CXCL10 and soluble PD-L1 (sPD-L1)) in blood or ETAs and SARS-CoV-2 status. We then stratified our cohort into SARS-CoV-2-negative and-positive groups and tested for associations between interferon-inducible mediators and clinical outcomes and SARS-CoV-2-copy-number. We used cytometry time-of-flight (CyTOF) to simultaneously measure 39 cell surface and intracellular markers on peripheral blood mononuclear cells collected from a subset of patients with ARDS. We then compared immune cell signatures in subjects with vs. without SARS-CoV-2. Results: The mean APACHE III score was higher in SARS-CoV-2-negative vs.-positive subjects (80±30 vs. 69±29), but the groups were otherwise well-matched. SARS-CoV-2-positive subjects had higher plasma concentrations of IFN-γ, CXCL10, and sPD-L1 relative to SARSCoV-2-negative patients adjusting for age, sex, and severity of illness (all p ≤ 0.01). The levels of IL-6, TNF-α, IL-8, MCP-1, and IL-17A were not significantly different between the two groups. SARS-CoV-2-positive subjects also had higher CXCL10 concentrations in ETAs than SARS-CoV-2-negative subjects. Higher plasma concentrations of CXCL10 and sPD-L1 were associated with higher mortality (Table 1) and more severe respiratory disease (ventilator-free days (VFDs), ARDS) in SARS-CoV-2-positive, but not-negative, patients. In contrast, higher IL-6 was associated with a lower number of VFDs and ARDS in both groups. IFN-γ and CXCL10 (but not IL-6) were associated with SARS-CoV-2-copy-number. Using CyTOF, we found SARS-CoV-2-positive subjects had a lower proportion of CXCR3+ (CXCL10 receptor) T-cells, a higher proportion of PD-L1+ monocytes, and less T-cell and monocyte intracellular cytokine staining vs. SARS-CoV-2-negative patients. Conclusion: Our findings suggest interferon-inducible mediator responses and immune cell hypofunction are characteristic of critically ill subjects with SARS-CoV-2 compared with similar patients without SARS-CoV-2. Our identification of immune signatures that are associated with SARS-CoV-2 infection but are distinct from other forms of critical illness clarifies COVID-19 pathophysiology.

Comparison of host endothelial, epithelial and inflammatory response in ICU patients with and without COVID-19

Rationale: Analyses of blood biomarkers involved in the host response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral infection can reveal distinct biological pathways and inform development and testing of therapeutics for COVID-19. Objective: To evaluate host endothelial, epithelial and inflammatory biomarkers in COVID-19Methods: We prospectively enrolled 169 ICU patients with suspicion of COVID-19 infection, including 78 (46%) patients positive and 91 (54%) negative for SARS-CoV-2 infection from April to September, 2020. We compared 22 plasma biomarkers in blood collected within 24 hours and 3 days after ICU admission. Measurement and Main Results: ICU patients with and without COVID-19 had similar rates of severe acute kidney injury, shock, thromboembolism and in-hospital mortality. Rates of ARDS were higher in COVID-19 (aRR = 5.9, 95% CI: 3.2-11.0). While concentrations of interleukin 6 and 8 were not different between groups, markers of epithelial cell injury (soluble receptor for advanced glycation end products, sRAGE) and acute phase proteins (serum amyloid A, SAA) were significantly higher in COVID-19 compared to non-COVID-19, adjusting for demographics and APACHE III scores (Figure 1). In contrast, angiopoietin 2:1 (Ang-2:1 ratio) and soluble tumor necrosis factor receptor 1 (sTNFR-1), markers of endothelial dysfunction and inflammation, were significantly lower in COVID-19 (Bonferroni corrected p<0.002). Ang-2:1 ratio and SAA were associated with mortality only in non-COVID-19 patients.Conclusions: These studies demonstrate that, unlike other well-studied causes of critical illness, endothelial dysfunction is not characteristic of severe COVID-19 early after ICU admission. Pathways resulting in elaboration of acute phase proteins and inducing epithelial cell injury may be promising targets for therapeutics. 2 (Table Presented).