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1.
Front Immunol ; 12: 748566, 2021.
Article in English | MEDLINE | ID: covidwho-1463474

ABSTRACT

Coronavirus disease 2019 (COVID-19) remains a major health challenge globally. Previous studies have suggested that changes in the glycosylation of IgG are closely associated with the severity of COVID-19. This study aimed to compare the profiles of IgG N-glycome between COVID-19 patients and healthy controls. A case-control study was conducted, in which 104 COVID-19 patients and 104 age- and sex-matched healthy individuals were recruited. Serum IgG N-glycome composition was analyzed by hydrophilic interaction liquid chromatography with the ultra-high-performance liquid chromatography (HILIC-UPLC) approach. COVID-19 patients have a decreased level of IgG fucosylation, which upregulates antibody-dependent cell cytotoxicity (ADCC) in acute immune responses. In severe cases, a low level of IgG sialylation contributes to the ADCC-regulated enhancement of inflammatory cytokines. The decreases in sialylation and galactosylation play a role in COVID-19 pathogenesis via the activation of the lectin-initiated alternative complement pathway. IgG N-glycosylation underlines the complex clinical phenotypes of SARS-CoV-2 infection.


Subject(s)
COVID-19/metabolism , Immunoglobulin G/metabolism , SARS-CoV-2/physiology , Adult , Antibody-Dependent Cell Cytotoxicity , Case-Control Studies , Chromatography, High Pressure Liquid , Complement Pathway, Mannose-Binding Lectin , Female , Glycosylation , Humans , Male , Middle Aged , Phenotype
2.
Front Immunol ; 12: 742446, 2021.
Article in English | MEDLINE | ID: covidwho-1441112

ABSTRACT

Background: The SARS-CoV-2 infection triggers excessive immune response resulting in increased levels of pro-inflammatory cytokines, endothelial injury, and intravascular coagulopathy. The complement system (CS) activation participates to this hyperinflammatory response. However, it is still unclear which activation pathways (classical, alternative, or lectin pathway) pilots the effector mechanisms that contribute to critical illness. To better understand the immune correlates of disease severity, we performed an analysis of CS activation pathways and components in samples collected from COVID-19 patients hospitalized in Grenoble Alpes University Hospital between 1 and 30 April 2020 and of their relationship with the clinical outcomes. Methods: We conducted a retrospective, single-center study cohort in 74 hospitalized patients with RT-PCR-proven COVID-19. The functional activities of classical, alternative, and mannose-binding lectin (MBL) pathways and the antigenic levels of the individual components C1q, C4, C3, C5, Factor B, and MBL were measured in patients' samples during hospital admission. Hierarchical clustering with the Ward method was performed in order to identify clusters of patients with similar characteristics of complement markers. Age was included in the model. Then, the clusters were compared with the patient clinical features: rate of intensive care unit (ICU) admission, corticoid treatment, oxygen requirement, and mortality. Results: Four clusters were identified according to complement parameters. Among them, two clusters revealed remarkable profiles: in one cluster (n = 15), patients exhibited activation of alternative and lectin pathways and low antigenic levels of MBL, C4, C3, Factor B, and C5 compared to all the other clusters; this cluster had the higher proportion of patients who died (27%) and required oxygen support (80%) or ICU care (53%). In contrast, the second cluster (n = 19) presented inflammatory profile with high classical pathway activity and antigenic levels of complement components; a low proportion of patients required ICU care (26%) and no patient died in this group. Conclusion: These findings argue in favor of prominent activation of the alternative and MBL complement pathways in severe COVID-19, but the spectrum of complement involvement seems to be heterogeneous requiring larger studies.


Subject(s)
COVID-19/immunology , COVID-19/mortality , Complement Pathway, Mannose-Binding Lectin , SARS-CoV-2 , Adult , Aged , Aged, 80 and over , Complement System Proteins/immunology , Female , Humans , Male , Middle Aged , Retrospective Studies
3.
J Autoimmun ; 124: 102728, 2021 11.
Article in English | MEDLINE | ID: covidwho-1440155

ABSTRACT

Extremely rare reactions characterized by thrombosis and thrombocytopenia have been described in subjects that received ChAdOx1 nCoV-19 vaccination 5-16 days earlier. Although patients with vaccine-induced thrombotic thrombocytopenia (VITT) have high levels of antibodies to platelet factor 4 (PF4)-polyanion complexes, the exact mechanism of the development of thrombosis is still unknown. Here we reported serum studies as well as proteomics and genomics analyses demonstrating a massive complement activation potentially linked to the presence of anti-PF4 antibodies in a patient with severe VITT. At admission, complement activity of the classical and lectin pathways were absent (0% for both) with normal levels of the alternative pathway (73%) in association with elevated levels of the complement activation marker sC5b-9 (630 ng/mL [n.v. 139-462 ng/mL]) and anti-PF4 IgG (1.918 OD [n.v. 0.136-0.300 OD]). The immunoblotting analysis of C2 showed the complete disappearance of its normal band at 110 kDa. Intravenous immunoglobulin treatment allowed to recover complement activity of the classical pathway (91%) and lectin pathway (115%), to reduce levels of sC5b-9 (135 ng/mL) and anti-PF4 IgG (0.681 OD) and to normalize the C2 pattern at immunoblotting. Proteomics and genomics analyses in addition to serum studies showed that the absence of complement activity during VITT was not linked to alterations of the C2 gene but rather to a strong complement activation leading to C2 consumption. Our data in a single patient suggest monitoring complement parameters in other VITT patients considering also the possibility to target complement activation with specific drugs.


Subject(s)
COVID-19 Vaccines/adverse effects , COVID-19/prevention & control , Complement C2 , Complement Membrane Attack Complex , Complement Pathway, Classical , Complement Pathway, Mannose-Binding Lectin , Purpura, Thrombotic Thrombocytopenic , SARS-CoV-2 , Adult , Autoantibodies/blood , COVID-19 Vaccines/administration & dosage , Complement C2/genetics , Complement C2/metabolism , Complement Membrane Attack Complex/genetics , Complement Membrane Attack Complex/metabolism , Complement Pathway, Classical/drug effects , Complement Pathway, Classical/genetics , Complement Pathway, Mannose-Binding Lectin/drug effects , Complement Pathway, Mannose-Binding Lectin/genetics , Female , Humans , Platelet Factor 4/blood , Purpura, Thrombotic Thrombocytopenic/blood , Purpura, Thrombotic Thrombocytopenic/chemically induced , Purpura, Thrombotic Thrombocytopenic/genetics
5.
Front Immunol ; 12: 671052, 2021.
Article in English | MEDLINE | ID: covidwho-1231338

ABSTRACT

We do not understand why non-white ethnicity and chronic kidney disease increase susceptibility to COVID-19. The lectin pathway of complement activation is a key contributor to innate immunity and inflammation. Concentrations of plasma lectin pathway proteins influence pathway activity and vary with ethnicity. We measured circulating lectin proteins in a multi-ethnic cohort of chronic kidney disease patients with and without COVID19 infection to determine if lectin pathway activation was contributing to COVID19 severity. We measured 11 lectin proteins in serial samples from a cohort of 33 patients with chronic kidney impairment and COVID19. Controls were single plasma samples from 32 patients on dialysis and 32 healthy individuals. We demonstrated multiple associations between recognition molecules and associated proteases of the lectin pathway and COVID-19, including COVID-19 severity. Some of these associations were unique to patients of Asian and White ethnicity. Our novel findings demonstrate that COVID19 infection alters the concentration of plasma lectin proteins and some of these changes were linked to ethnicity. This suggests a role for the lectin pathway in the host response to COVID-19 and suggest that variability within this pathway may contribute to ethnicity-associated differences in susceptibility to severe COVID-19.


Subject(s)
COVID-19/blood , Complement Pathway, Mannose-Binding Lectin , Lectins/blood , Renal Insufficiency, Chronic/blood , SARS-CoV-2/metabolism , Adult , Aged , Aged, 80 and over , COVID-19/ethnology , COVID-19/immunology , COVID-19/pathology , Female , Humans , Lectins/immunology , Male , Middle Aged , Renal Insufficiency, Chronic/ethnology , Renal Insufficiency, Chronic/immunology , Renal Insufficiency, Chronic/pathology , SARS-CoV-2/immunology
6.
Front Immunol ; 11: 585243, 2020.
Article in English | MEDLINE | ID: covidwho-976265

ABSTRACT

Lung diseases are among the leading causes of morbidity and mortality. Complement activation may prevent a variety of respiratory infections, but on the other hand, could exacerbate tissue damage or contribute to adverse side effects. In this review, the associations of factors specific for complement activation via the lectin pathway (LP) with infections of the respiratory system, from birth to adulthood, are discussed. The most extensive data concern mannose-binding lectin (MBL) which together with other collectins (collectin-10, collectin-11) and the ficolins (ficolin-1, ficolin-2, ficolin-3) belong to pattern-recognition molecules (PRM) specific for the LP. Those PRM form complexes with MBL-associated serine proteases (MASP-1, MASP-2, MASP-3) and related non-enzymatic factors (MAp19, MAp44). Beside diseases affecting humanity for centuries like tuberculosis or neonatal pneumonia, some recently published data concerning COVID-19 are summarized.


Subject(s)
COVID-19/immunology , Complement System Proteins/immunology , Mannose-Binding Lectin/immunology , Respiratory System/immunology , SARS-CoV-2/physiology , Animals , COVID-19/genetics , COVID-19/virology , Complement Activation , Complement Pathway, Mannose-Binding Lectin , Complement System Proteins/genetics , Humans , Mannose-Binding Lectin/genetics , Respiratory System/virology , SARS-CoV-2/genetics , SARS-CoV-2/immunology
8.
Immunobiology ; 225(6): 152001, 2020 11.
Article in English | MEDLINE | ID: covidwho-696536

ABSTRACT

In COVID-19, acute respiratory distress syndrome (ARDS) and thrombotic events are frequent, life-threatening complications. Autopsies commonly show arterial thrombosis and severe endothelial damage. Endothelial damage, which can play an early and central pathogenic role in ARDS and thrombosis, activates the lectin pathway of complement. Mannan-binding lectin-associated serine protease-2 (MASP-2), the lectin pathway's effector enzyme, binds the nucleocapsid protein of severe acute respiratory syndrome-associated coronavirus-2 (SARS-CoV-2), resulting in complement activation and lung injury. Narsoplimab, a fully human immunoglobulin gamma 4 (IgG4) monoclonal antibody against MASP-2, inhibits lectin pathway activation and has anticoagulant effects. In this study, the first time a lectin-pathway inhibitor was used to treat COVID-19, six COVID-19 patients with ARDS requiring continuous positive airway pressure (CPAP) or intubation received narsoplimab under compassionate use. At baseline and during treatment, circulating endothelial cell (CEC) counts and serum levels of interleukin-6 (IL-6), interleukin-8 (IL-8), C-reactive protein (CRP) and lactate dehydrogenase (LDH) were assessed. Narsoplimab treatment was associated with rapid and sustained reduction of CEC and concurrent reduction of serum IL-6, IL-8, CRP and LDH. Narsoplimab was well tolerated; no adverse drug reactions were reported. Two control groups were used for retrospective comparison, both showing significantly higher mortality than the narsoplimab-treated group. All narsoplimab-treated patients recovered and survived. Narsoplimab may be an effective treatment for COVID-19 by reducing COVID-19-related endothelial cell damage and the resultant inflammation and thrombotic risk.


Subject(s)
Antibodies, Monoclonal/therapeutic use , COVID-19/immunology , Complement Pathway, Mannose-Binding Lectin/drug effects , Endothelium, Vascular/drug effects , SARS-CoV-2/immunology , Thrombotic Microangiopathies/drug therapy , Antibodies, Monoclonal/immunology , C-Reactive Protein/immunology , C-Reactive Protein/metabolism , COVID-19/complications , COVID-19/virology , Complement Pathway, Mannose-Binding Lectin/immunology , Endothelium, Vascular/immunology , Endothelium, Vascular/pathology , Female , Humans , Immunoglobulin G/immunology , Immunoglobulin G/therapeutic use , Inflammation/complications , Inflammation/immunology , Inflammation/prevention & control , Interleukin-6/blood , Interleukin-6/immunology , Male , Mannose-Binding Protein-Associated Serine Proteases/antagonists & inhibitors , Mannose-Binding Protein-Associated Serine Proteases/immunology , Mannose-Binding Protein-Associated Serine Proteases/metabolism , Middle Aged , Outcome Assessment, Health Care/methods , Outcome Assessment, Health Care/statistics & numerical data , Retrospective Studies , SARS-CoV-2/physiology , Thrombotic Microangiopathies/complications , Thrombotic Microangiopathies/immunology
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