ABSTRACT
The different effector functions of human IgG are closely associated with its four subtypes. Class switch towards IgG4 occurs after long-term antigen exposure, downregulates immune responses and is associated with several autoimmune diseases. Interestingly, significantly elevated IgG4 levels have recently been detected after more than two mRNA vaccinations. We here study the distribution of IgG subtypes in the context of Post-COVID syndrome. To this end, we analyzed serum samples from two cohorts of 64 patients after COVID and 64 convalescent COVID-19 patients. We found differences in the absolute levels of Spike protein-specific IgG subtypes for both cohorts. IgG1 was the most abundant subtype, followed by IgG3 and IgG2 and IgG4 in declining order. A significant difference was only detected for IgG2. When further analyzing the IgG4 levels reactive against the Spike protein receptor-binding domain (RBD) and the nucleocapsid-protein of SARS-CoV-2, a small but significant difference was detected for the RBD but not nucleocapsid proteins. Since the total IgG4 levels are very low, we do not expect a biologically relevant role in the development and progression of post-COVID syndrome. However, low IgG2 levels, as seen in the Post-COVID cohort, could contribute to the persistent presence of SARS-CoV-2 antigens, causing chronic inflammation in the setting of post-COVID.
Subject(s)
Autoimmune Diseases , COVID-19 , InflammationABSTRACT
Hyperinflammation is frequently observed in patients with severe COVID-19. Inadequate and defective IFN type I responses against SARS-CoV-2, associated with autoantibodies in a proportion of patients, lead to severe courses of disease. In addition, hyperactive responses of the humoral immune system have been described. In the current study we investigated a possible role of neutralizing autoantibodies against anti-inflammatory mediators. Plasma from adult patients with severe and critical COVID-19 was screened by ELISA for antibodies against PGRN, IL-1-Ra, IL-10, IL-18BP, IL-22BP, IL-36-Ra, CD40, IFN-α2, IFN-γ, IFN-ω and serpinB1. Autoantibodies were characterized and the antigens were analyzed for immunogenic alterations. In a discovery cohort with severe to critical COVID-19 high titers of PGRN-autoantibodies were detected in 11 of 30 (36.7%), and of IL-1-Ra-autoantibodies in 14 of 30 (46.7%) patients. In a validation cohort of 64 patients with critical COVID-19 high-titer PGRN-Abs were detected in 25 (39%) and IL-1-Ra-Abs in 32 of 64 patients (50%). PGRN-Abs and IL-1-Ra-Abs belonged to IgM and several IgG subclasses. In separate cohorts with non-critical COVID-19, PGRN-Abs and IL-1-Ra-Abs were detected in low frequency (i.e. in < 5% of patients) and at low titers. Neither PGRN- nor IL-1-Ra-Abs were found in 40 healthy controls vaccinated against SARS-CoV-2 or 188 unvaccinated healthy controls. PGRN-Abs were not cross-reactive against SARS-CoV-2 structural proteins nor against IL-1-Ra. Plasma levels of both free PGRN and free IL-1-Ra were significantly decreased in autoantibody-positive patients compared to Ab-negative and non-COVID-19 controls. In vitro PGRN-Abs from patients functionally reduced PGRN-dependent inhibition of TNF-α signaling, and IL-1-Ra-Abs from patients reduced IL-1-Ra- or anakinra-dependent inhibition of IL-1ß signaling. The pSer81 hyperphosphorylated PGRN isoform was exclusively detected in patients with high-titer PGRN-Abs; likewise, a hyperphosphorylated IL-1-Ra isoform was only found in patients with high-titer IL-1-Ra-Abs. Thr111 was identified as the hyperphophorylated amino acid of IL-1-Ra. In longitudinally collected samples hyperphosphorylated isoforms of both PGRN and IL-1-Ra emerged transiently, and preceded the appearance of autoantibodies. In hospitalized patients, the presence of IL-1-Ra-Abs or IL-1-Ra-Abs in combination with PGRN-Abs was associated with a higher morbidity and mortality.To conclude, neutralizing autoantibodies to IL-1-Ra and PGRN occur in a significant portion of patients with critical COVID-19, with a concomitant decrease in circulating free PGRN and IL-1-Ra, indicative of a misdirected, proinflammatory autoimmune response. The break of self-tolerance is likely caused by atypical hyperphosphorylated isoforms of both antigens, whose appearances precede autoantibody induction. Our data suggest that these immunogenic secondary modifications are induced by the SARS-CoV-2-infection itself or the inflammatory environment evoked by the infection and predispose for a critical course of COVID-19.
Subject(s)
COVID-19ABSTRACT
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
Background: There is ongoing debate whether lung physiology of COVID-19 associated acute respiratory distress syndrome (ARDS) differs from ARDS of other origin.Objective: The aim of this study was to analyze and compare how critically ill patients with COVID-19 and Influenza A or B were ventilated in our tertiary care center with or without extracorporeal membrane oxygenation (ECMO). We ask if acute lung failure due to COVID-19 requires different intensive care management compared to conventional ARDS. Methods: 25 patients with COVID-19 associated ARDS were matched to a cohort of 25 Influenza patients treated in our center from 2011 to 2021. Subgroup analysis addressed whether patients on ECMO received different mechanical ventilation than patients without extracorporeal support.Results: Compared to Influenza-associated ARDS, COVID-19 patients had higher ventilatory system compliance (40.7 ml/mbar [31.8 – 46.7 ml/mbar] vs. 31.4 ml/mbar [13.7 – 42.8 ml/mbar], p = 0.198), higher ventilatory ratio (1.57 [1.31 – 1.84] vs. 0.91 [0.44 – 1.38], p = 0.006) and higher minute ventilation at the time of intubation (mean minute ventilation 10.7 l/min [7.2 – 12.2 l/min] for COVID-19 vs. 6.0 l/min [2.5 – 10.1 l/min] for Influenza, p = 0.013). There were no measurable differences in P/F ratio, positive end-expiratory pressure (PEEP) and driving pressures (ΔP). Respiratory system compliance deteriorated considerably in COVID-19 patients on ECMO during 2 weeks of mechanical ventilation (Crs, mean decrease over 2 weeks -23.87 ml/mbar ± 32.94 ml/mbar, p = 0.037), but not in ventilated Influenza patients on ECMO and less so in ventilated COVID-19 patients without ECMO. For COVID-19 patients, low driving pressures on ECMO were strongly correlated to a decline in compliance after 2 weeks (Pearson’s R 0.80, p = 0.058). Overall mortality was insignificantly lower for COVID-19 patients compared to Influenza patients (40% vs. 48%, p = 0.31). Outcome was insignificantly worse for patients requiring veno-venous ECMO in both groups (50% mortality for COVID-19 on ECMO vs. 27% without ECMO, p = 0.30 / 56% vs 34% mortality for Influenza A/B with and without ECMO, p = 0.31)Conclusion: The pathophysiology of early COVID-19-associated ARDS differs from Influenza-associated acute lung failure by sustained respiratory mechanics during the early phase of ventilation. We question whether intubated COVID-19 patients on ECMO benefit from extremely low driving pressures, as this appears to accelerate derecruitment and consecutive loss of ventilatory system compliance.
Subject(s)
COVID-19ABSTRACT
INTRODUCTION: Hyperinflammation is frequently observed in patients with severe COVID-19. Inadequate and defective IFN type I responses against SARS-CoV-2, caused by autoantibodies in a proportion of patients, lead to severe courses. In addition, hyperactive responses of the humoral immune system have been described so far. RATIONALE: In the current study we investigated a possible role of neutralizing autoantibodies against anti-inflammatory mediators. Plasma from patients with severe and critical COVID-19 was screened by ELISA for antibodies against PGRN, IL-10, IL-18BP, IL-22BP and IL-1-RA. Autoantibodies were characterized and the antigens were analyzed for immunogenic alterations. RESULTS: PGRN-autoantibodies were detected with high titers in 11 of 30 (36.7%), and IL 1-RA-autoantibodies in 14 of 30 (46.7%) patients of a discovery cohort with severe to critical COVID-19. In a validation cohort of 41 patients with critical COVID-19 high-titered PGRN-Abs were detected in 12 (29.3%) and IL-1-RA-Abs in 19 of 41 patients (46.2%). PGRN-Abs and IL-1-RA-Abs belonged to IgM and several IgG subclasses. In separate cohorts with non-critical COVID-19, PGRN-Abs and IL-1-RA-Abs were detected significantly less frequently and at low titers. Neither PGRN- nor IL-1-RA-Abs were found in 40 healthy controls vaccinated against SARS-CoV-2. PGRN-Abs were not cross-reactive against SARS-CoV-2 structural proteins or against IL-1-RA. Plasma levels of both free PGRN and IL-1-RA were significantly decreased in autoantibody-positive patients compared to Ab-negative and non-COVID controls. Functionally, PGRN-Abs from patients reduced PGRN-dependent inhibition of TNF- signaling in vitro. The pSer81 hyperphosphorylated PGRN isoform was exclusively detected in patients with high-titer PGRN-Abs; likewise, a yet unidentified hyperphosphorylated IL-1-RA isoform was only found in patients with high-titer IL-1-RA-Abs. No autoantibodies against IL-10, IL-18BP or IL-22BP were found. CONCLUSION: To conclude, neutralizing autoantibodies to IL-1-RA and PGRN occur in a significant proportion of patients with critical COVID-19, with a concomitant decrease in circulating PGRN and IL-1-RA, which is indicative of a misdirected, proinflammatory autoimmune response. The break of self-tolerance is likely caused by atypical isoforms of both antigens due to hyperphosphorylation. It remains to be determined whether these secondary modifications are induced by the SARS-CoV-2-infection itself, or are preexisting and predispose for a critical course.
Subject(s)
Severe Acute Respiratory Syndrome , Frontotemporal Dementia , COVID-19ABSTRACT
Rationale: The treatment options for COVID-19 patients are sparse and do not show sufficient efficacy. Alpha-1-antitrypsin (AAT) is a multi-functional host-defense protein with anti-proteolytic and anti-inflammatory activities. Objectives: The aim of the present study was to evaluate whether AAT is a suitable candidate for treatment of COVID-19. Methods: AAT and inflammatory markers were measured in the serum of COVID-19 patients. Human cell cultures were employed to determine the cell-based anti-protease activity of AAT and to test whether AAT inhibits the host cell entry of vesicular stomatitis virus (VSV) particles bearing the spike (S) protein of SARS-CoV-2 and the replication of authentic SARS-CoV-2. Inhaled and / or intravenous AAT was applied to nine patients with mild-to-moderate COVID-19. Measurements and Main Results: The serum AAT concentration in COVID-19 patients was increased as compared to control patients. The relative AAT concentrations were decreased in severe COVID-19 or in non-survivors in ratio to inflammatory blood biomarkers. AAT inhibited serine protease activity in human cell cultures, the uptake of VSV-S into airway cell lines and the replication of SARS-CoV-2 in human lung organoids. All patients, who received AAT, survived and showed decreasing respiratory distress, inflammatory markers, and viral load. Conclusion: AAT has anti-SARS-CoV-2 activity in human cell models, is well tolerated in patients with COVID-19 and together with its anti-inflammatory properties might be a good candidate for treatment of COVID-19.
Subject(s)
Vesicular Stomatitis , COVID-19ABSTRACT
Extracorporeal membrane oxygenation (ECMO) is a means to support patients with acute respiratory failure. Initially, recommendations to treat severe cases of pandemic Coronavirus Disease 2019 (COVID-19) with ECMO have been restrained. In the meantime, ECMO has been shown to produce similar outcomes in patients with severe COVID-19 compared to existing data on ARDS mortality.Objective: We performed an international email survey to assess how ECMO providers worldwide have previously used ECMO during the treatment of critically ill patients with COVID-19.MethodsA questionnaire with 45 questions (covering e.g. indication, technical aspects, benefit and reasons for treatment discontinuation), mostly multiple-choice, was distributed by email to ECMO centers. The survey was approved by the European branch of the Extracorporeal Life Support Organization (ELSO).Results: 276 centers worldwide responded that they employed ECMO for very severe COVID-19 cases, mostly in veno-venous configuration (87%). The most common reason to establish ECMO was isolated hypoxemic respiratory failure (50%), followed by a combination of hypoxemia and hypercapnia (39%). Only a small fraction of patients required veno-arterial cannulation due to heart failure (3%). Time on ECMO varied between less than two and more than four weeks. The main reason to discontinue ECMO treatment prior to patient’s recovery was lack of clinical improvement (53%), followed by major bleeding, mostly intracranially (13%). Only 4% of respondents reported that triage situations, lack of staff or lack of oxygenators were responsible for discontinuation of ECMO support. Most ECMO physicians (66% ± 26%) agreed that patients with COVID-19 induced ARDS (CARDS) benefitted from ECMO. Overall mortality of COVID-19 patients on ECMO was estimated to be about 55%, scoring higher than what has previously been reported for Influenza patients on ECMO (29 – 36%).Conclusion: ECMO has been utilized successfully during the COVID-19 pandemic to stabilize CARDS patients in hypoxemic or hypercapnic lung failure. Age and multimorbidity limited the use of ECMO. Triage situations were rarely a concern. ECMO providers stated that patients with severe COVID-19 benefitted from ECMO. An increasing use in patients with respiratory failure in a future stage of the pandemic may be expected.Funding Statement: COVID-19 research was funded by the Federal state of Saarland, Saarland University and Dr. Rolf M. Schwiete Foundation.Declaration of Interests: Robert Bals declares funding from AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, Grifols, Novartis, CLS Behring, the German Federal Ministry of Education and Research (BMBF) Competence Network Asthma and COPD (ASCONET), Sander-Stiftung, Schwiete-Stiftung, Krebshilfe and Mukoviszidose eV. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed. All other authors: No potential conflicts of interest.Ethics Approval Statement: The ethical committee (Ärztekammer des Saarlandes) waived the need for a formal approval since the questionnaire did not retrieve actual patient data.
Subject(s)
Coronavirus Infections , Heart Failure , Lung Diseases , Respiratory Distress Syndrome , Pulmonary Disease, Chronic Obstructive , Coffin-Lowry Syndrome , COVID-19 , Hypercapnia , Respiratory InsufficiencyABSTRACT
Background In 2020, a novel coronavirus caused a global pandemic with a clinical picture termed COVID-19 accounting for numerous cases of ARDS. However, there are still other infectious causes of ARDS that should be considered, especially, as the majority of these pathogens are specifically treatable. Case Presentation We present the case of a 36-year-old gentleman who was admitted to the hospital with flu-like symptoms after completing a half-marathon one week before admission. As infection with SARS-CoV2 was suspected based on radiologic imaging, the hypoxemic patient was immediately transferred to the ICU, where he developed ARDS. Empiric antimicrobial chemotherapy was initiated, the patient deteriorated further, therapy was changed and the patient was transferred to a tertiary care ARDS center. As cold agglutinins were present, the hypothesis of an infection with SARS-CoV-2 was then questioned. Bronchoscopic sampling revealed Mycoplasma (M.) pneumoniae. When antimicrobial chemotherapy was adjusted, the patient recovered quickly. Conclusion Usually, M. pneumoniae causes mild disease. When antimicrobial chemotherapy was adjusted, the patient recovered quickly. The case underlines the importance of adhering to established treatment guidelines, scrutinizing treatment modalities and not forgetting other potential causes of severe pneumonia or ARDS.
Subject(s)
COVID-19 , Pneumonia , Respiratory Distress SyndromeABSTRACT
Background: It has been suggested that COVID-19-associated severe respiratory failure (CARDS) might differ from usual acute respiratory distress syndrome (ARDS) due to failing auto-regulation of pulmonary vessels and higher shunt. We sought to investigate pulmonary hemodynamics and ventilation properties in patients with CARDS compared to patients with ARDS of pulmonary origin. Methods: Retrospective analysis of prospectively collected data of consecutive adults with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 patients treated on our ICU in 04/2020 and comparison of the data to matched controls with ARDS due to respiratory infections treated on our ICU from 01/2014 to 08/2019 and for whom pulmonary artery catheter data were available. Results: CARDS patients (n = 10) had similar ventilation characteristics as compared to ARDS (n = 10) patients. Still, mechanical power applied by ventilation was significantly higher in CARDS patients (23.4 ± 8.9 J/min) than in ARDS (15.9 ± 4.3 J/min; p<0.05). COVID-19 patients had similar pulmonary artery pressure but significantly lower pulmonary vascular resistance, as cardiac output was higher in CARDS vs. ARDS patients (p<0.05). Shunt fraction and dead space were similar in CARDS compared to ARDS (p>0.05) and was in both groups correlated with hypoxemia. The arterio-venous pCO2 difference (DpCO2) was elevated (CARDS 5.5±2.8 mmHg vs. ARDS 4.7±1.1 mmHg; p>0.05) as was P(v-a)CO2/C(a-v)O2 ratio (CARDS mean 2.2±1.5 vs. ARDS 1.7±0.8; p>0.05). Conclusions: Respiratory failure in COVID-19 patients seems to differ only slightly from ARDS regarding ventilation characteristics and pulmonary hemodynamics. Differences are mainly due to increased CO2 production in CARDS patients. Our data indicate microcirculatory dysfunction. More data needs to be collected to assure these findings and gain more pathophysiological insights in COVID-19 and respiratory failure.
Subject(s)
Respiratory Distress Syndrome , Hypoxia , Respiratory Tract Infections , COVID-19 , Familial Primary Pulmonary Hypertension , Respiratory InsufficiencyABSTRACT
Patients infected with SARS-CoV-2 differ in the severity of disease. In this study, SARS-CoV-2 specific T-cells and antibodies were characterized in patients with different COVID-19 related disease severity. Despite severe lymphopenia affecting all major lymphocyte subpopulations, patients with severe disease mounted significantly higher levels of SARS-CoV-2 specific T-cells as compared to convalescent individuals. SARS-CoV-2 specific CD4 T-cells dominated over CD8 T-cells and closely correlated with the number of plasmablasts and SARS-CoV-2 specific IgA- and IgG-levels. Unlike in convalescents, SARS-CoV-2 specific T-cells in patients with severe disease showed marked alterations in phenotypical and functional properties, which also extended to CD4 and CD8 T-cells in general. Given the strong induction of specific immunity to control viral replication in patients with severe disease, the functionally altered phenotype may result from the need for contraction of specific and general immunity to counteract excessive immunopathology in the lung.