Alexandre Bélot
A5043853010- Autoimmune and Inflammatory Disorders Research
- Inflammasome and immune disorders
- Systemic Lupus Erythematosus Research
- Immunodeficiency and Autoimmune Disorders
- Kawasaki Disease and Coronary Complications
- interferon and immune responses
- Adolescent and Pediatric Healthcare
- COVID-19 Clinical Research Studies
- Immune Cell Function and Interaction
- SARS-CoV-2 and COVID-19 Research
- Otitis Media and Relapsing Polychondritis
- Diabetes and associated disorders
- Vasculitis and related conditions
- Renal Diseases and Glomerulopathies
- T-cell and B-cell Immunology
- Inflammatory Myopathies and Dermatomyositis
- Immune Response and Inflammation
- Long-Term Effects of COVID-19
- Respiratory viral infections research
- Coagulation, Bradykinin, Polyphosphates, and Angioedema
- Mechanical Circulatory Support Devices
- Atherosclerosis and Cardiovascular Diseases
- Acute Lymphoblastic Leukemia research
- Lymphoma Diagnosis and Treatment
- Parvovirus B19 Infection Studies
Hospices Civils de Lyon
2016-2025
Centre International de Recherche en Infectiologie
2016-2025
Hôpital Femme Mère Enfant
2016-2025
Université Claude Bernard Lyon 1
2016-2025
Centre National de la Recherche Scientifique
2016-2025
Inserm
2016-2025
École Normale Supérieure de Lyon
2016-2025
The Lymphoma Academic Research Organisation
2021-2025
ERN GUARD-Heart
2025
Hôpital Lyon Sud
2018-2024
Interindividual clinical variability in the course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is vast. We report that at least 101 987 patients with life-threatening disease 2019 (COVID-19) pneumonia had neutralizing immunoglobulin G (IgG) autoantibodies (auto-Abs) against interferon-ω (IFN-ω) (13 patients), 13 types IFN-α (36), or both (52) onset critical disease; a few also auto-Abs other three type I IFNs. The neutralize ability corresponding IFNs to block...
<h3>Objectives</h3> To validate the previously proposed classification criteria for Henoch–Schönlein purpura (HSP), childhood polyarteritis nodosa (c-PAN), c-Wegener granulomatosis (c-WG) and c-Takayasu arteritis (c-TA). <h3>Methods</h3> Step 1: retrospective/prospective web-data collection children with HSP, c-PAN, c-WG c-TA age at diagnosis ≤18 years. 2: blinded by consensus panel of a representative sample 280 cases. 3: statistical (sensitivity, specificity, area under curve κ-agreement)...
Circulating autoantibodies (auto-Abs) neutralizing high concentrations (10 ng/mL, in plasma diluted 1 to 10) of IFN-α and/or -ω are found about 10% patients with critical COVID-19 pneumonia, but not subjects asymptomatic infections. We detect auto-Abs 100-fold lower, more physiological, (100 pg/mL, 1/10 dilutions plasma) 13.6% 3,595 COVID-19, including 21% 374 > 80 years, and 6.5% 522 severe COVID-19. These antibodies also detected 18% the 1,124 deceased (aged 20 days-99 years; mean: 70...
<h3>Importance</h3> Multisystem inflammatory syndrome in children (MIS-C) is the most severe pediatric disease associated with acute respiratory coronavirus 2 infection, potentially life-threatening, but optimal therapeutic strategy remains unknown. <h3>Objective</h3> To compare intravenous immunoglobulins (IVIG) plus methylprednisolone vs IVIG alone as initial therapy MIS-C. <h3>Design, Setting, and Participants</h3> Retrospective cohort study drawn from a national surveillance system...
Type I interferons (IFNs) are essential mediators of antiviral responses. These cytokines have been implicated in the pathogenesis autoimmunity, most notably systemic lupus erythematosus (SLE), diabetes mellitus, and dermatomyositis, as well monogenic type interferonopathies. Despite a fundamental role health disease, direct quantification IFNs has challenging. Using single-molecule array (Simoa) digital ELISA technology, we recorded attomolar concentrations IFNα healthy donors, viral...
End of April 2020, French clinicians observed an increase in cases presenting with paediatric inflammatory multisystem syndrome (PIMS). Nationwide surveillance was set up and demonstrated temporospatial association the coronavirus disease (COVID-19) epidemic for 156 reported as at 17 May: 108 were classified confirmed (n = 79), probable 16) or possible 13) post-COVID-19 PIMS cases. A continuum clinical features from Kawasaki-like to myocarditis observed, requiring intensive care 67%
There is little known about the impact of SARS-CoV-2 on patients with inflammatory rheumatic and musculoskeletal diseases (iRMD). We examined epidemiological characteristics associated severe disease, then death. also compared mortality between hospitalised for COVID-19 without iRMD.Individuals suspected iRMD-COVID-19 were included in this French cohort. Logistic regression models adjusted age sex used to estimate ORs 95% CIs COVID-19. The most significant clinically relevant factors...
Significance There is growing evidence that preexisting autoantibodies neutralizing type I interferons (IFNs) are strong determinants of life-threatening COVID-19 pneumonia. It important to estimate their quantitative impact on mortality upon SARS-CoV-2 infection, by age and sex, as both the prevalence these risk death increase with higher in men. Using an unvaccinated sample 1,261 deceased patients 34,159 individuals from general population, we found against IFNs strongly increased...
MIS-C is characterized by a polyclonal activation of Vβ21.3 + CD4 and CD8 T cells that poorly respond to SARS-CoV-2 antigens.
IFN-I and IFN-III immunity in the nasal mucosa is poorly characterized during SARS-CoV-2 infection. We analyze IFN-I/III signature, namely expression of ISGF-3-dependent IFN-stimulated genes, mildly symptomatic COVID-19 patients show its correlation with serum IFN-α2 levels, which peak at symptom onset return to baseline from day 10 onward. Moreover, signature correlates nasopharyngeal viral load associated presence infectious viruses. By contrast, we observe low scores despite high loads a...
Multisystem inflammatory syndrome in children (MIS-C) is a rare and severe condition that follows benign COVID-19. We report autosomal recessive deficiencies of OAS1 , OAS2 or RNASEL five unrelated with MIS-C. The cytosolic double-stranded RNA (dsRNA)–sensing generate 2′-5′-linked oligoadenylates (2-5A) activate the single-stranded RNA–degrading ribonuclease L (RNase L). Monocytic cell lines primary myeloid cells OAS1, OAS2, RNase produce excessive amounts cytokines upon dsRNA acute...
Recessive or dominant inborn errors of type I interferon (IFN) immunity can underlie critical COVID-19 pneumonia in unvaccinated adults. The risk children, which is much lower than adults, remains unexplained. In an international cohort 112 children (&lt;16 yr old) hospitalized for pneumonia, we report 12 (10.7%) aged 1.5–13 with (7 children), severe (3), and moderate (2) 4 the 15 known clinically recessive biochemically complete IFN immunity: X-linked TLR7 deficiency children) autosomal...
In the 330-patient ADVOCATE trial of avacopan for treatment antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis, in which 81% patients had renal involvement, estimated glomerular filtration rate (eGFR) increased on average 7.3 ml/min per 1.73 m2 group and 4.1 prednisone (P = 0.029) at week 52. This new analysis examines results patient subgroup with severe insufficiency enrollment into trial, i.e., eGFR ≤20 m2.eGFR was determined baseline over course trial. Changes were...
Type I and III interferons (IFN-I/λ) are important antiviral mediators against SARS-CoV-2 infection. Here, we demonstrate that plasmacytoid dendritic cells (pDC) the predominant IFN-I/λ source following their sensing of SARS-CoV-2-infected cells. Mechanistically, this short-range by pDCs requires sustained integrin-mediated cell adhesion with infected In turn, restrict viral spread an response directed toward This specialized function enables to efficiently turn-off replication, likely via a...
We found that 19 (10.4%) of 183 unvaccinated children hospitalized for COVID-19 pneumonia had autoantibodies (auto-Abs) neutralizing type I IFNs (IFN-α2 in 10 patients: IFN-α2 only three, plus IFN-ω five, and IFN-α2, IFN-β two; nine patients). Seven (3.8%) Abs at least ng/ml one IFN, whereas the other 12 (6.6%) 100 pg/ml. The auto-Abs neutralized both unglycosylated glycosylated IFNs. also detected pg/ml 4 2,267 uninfected (0.2%) 45 (2%). odds ratios (ORs) life-threatening were, therefore,...
Systemic juvenile idiopathic arthritis (sJIA) and adult-onset Still's disease (AOSD) are considered the same disease, but a common approach for diagnosis management is still missing. In May 2022, EULAR PReS endorsed proposal joint task force (TF) to develop recommendations of sJIA AOSD. The TF agreed during first meeting address four topics: similarity between AOSD, diagnostic biomarkers, therapeutic targets strategies complications including macrophage activation syndrome (MAS). Systematic...