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Renaud C, Lewin A, Gregoire Y, Simard N, Vallières É, Paquette M, Drews SJ, O'Brien SF, Di Germanio C, Busch MP, Germain M, Bazin R. SARS-CoV-2 immunoassays in a predominantly vaccinated population: Performances and qualitative agreements obtained with two analytical approaches and four immunoassays. Vox Sang 2024. [PMID: 38577957 DOI: 10.1111/vox.13625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 01/18/2024] [Accepted: 03/15/2024] [Indexed: 04/06/2024]
Abstract
BACKGROUND AND OBJECTIVES Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serosurveys are typically analysed by applying a fixed threshold for seropositivity ('conventional approach'). However, this approach underestimates the seroprevalence of anti-nucleocapsid (N) in vaccinated individuals-who often exhibit a difficult-to-detect anti-N response. This limitation is compounded by delays between the onset of infection and sample collection. To address this issue, we compared the performance of four immunoassays using a new analytical approach ('ratio-based approach'), which determines seropositivity based on an increase in anti-N levels. MATERIALS AND METHODS Two groups of plasma donors and four immunoassays (Elecsys total anti-N, VITROS total anti-N, Architect anti-N Immunoglobulin G (IgG) and in-house total anti-N) were evaluated. First-group donors (N = 145) had one positive SARS-CoV-2 polymerase chain reaction (PCR) test result and had made two plasma donations, including one before and one after the PCR test (median = 27 days post-PCR). Second-group donors (N = 100) had made two plasma donations early in the Omicron wave. RESULTS Among first-group donors (97.9% vaccinated), sensitivity estimates ranged from 60.0% to 89.0% with the conventional approach, compared with 94.5% to 98.6% with the ratio-based approach. Among second-group donors, Fleiss's κ ranged from 0.56 to 0.83 with the conventional approach, compared with 0.90 to 1.00 with the ratio-based approach. CONCLUSION With the conventional approach, the sensitivity of four immunoassays-measured in a predominantly vaccinated population based on samples collected ~1 month after a positive test result-fell below regulatory agencies requirement of ≥95%. The ratio-based approach significantly improved the sensitivities and qualitative agreement among immunoassays, to the point where all would meet this requirement.
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Affiliation(s)
- Christian Renaud
- Medical Affairs and Innovation, Héma-Québec, Montréal, Quebec, Canada
| | - Antoine Lewin
- Medical Affairs and Innovation, Héma-Québec, Montréal, Quebec, Canada
| | - Yves Gregoire
- Medical Affairs and Innovation, Héma-Québec, Montréal, Quebec, Canada
| | - Nathalie Simard
- Medical Affairs and Innovation, Héma-Québec, Montréal, Quebec, Canada
| | - Émilie Vallières
- Division of Microbiology, Clinical Laboratory Medicine Department, Centre Hospitalier Universitaire Sainte-Justine, Montreal, Canada
- Division of Infectious Diseases, Pediatrics Department, Centre Hospitalier Universitaire Sainte-Justine, Montreal, Canada
| | - Maude Paquette
- Division of Microbiology, Clinical Laboratory Medicine Department, Centre Hospitalier Universitaire Sainte-Justine, Montreal, Canada
- Division of Infectious Diseases, Pediatrics Department, Centre Hospitalier Universitaire Sainte-Justine, Montreal, Canada
| | - Steven J Drews
- Canadian Blood Services, Microbiology, Edmonton, Alberta, Canada
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
| | - Sheila F O'Brien
- Epidemiology and Surveillance, Canadian Blood Services, Ottawa, Ontario, Canada
| | | | | | - Marc Germain
- Medical Affairs and Innovation, Héma-Québec, Montréal, Quebec, Canada
| | - Renée Bazin
- Medical Affairs and Innovation, Héma-Québec, Montréal, Quebec, Canada
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Askenase PW. COVID-19 therapy with mesenchymal stromal cells (MSC) and convalescent plasma must consider exosome involvement: Do the exosomes in convalescent plasma antagonize the weak immune antibodies? J Extracell Vesicles 2020; 10:e12004. [PMID: 33304473 PMCID: PMC7710130 DOI: 10.1002/jev2.12004] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/12/2020] [Accepted: 09/28/2020] [Indexed: 12/11/2022] Open
Abstract
Exosome extracellular vesicles as biologic therapy for COVID-19 are discussed for two areas. The first involves the growing use of mesenchymal stromal cells (MSCs) for the profound clinical cytokine storm and severe pneumonia in COVID-19 patients. Instead, it is recommended to treat alternatively with their MSC-released exosomes. This is because many reports in the literature and our data have shown that the release of exosomes from the in vivo administered MSC is actually responsible for their beneficial effects. Further, the exosomes are superior, simpler and clinically more convenient compared to their parental MSC. Additionally, in the context of COVID-19, the known tendency of MSC to intravascularly aggregate causing lung dysfunction might synergize with the pneumonia aspects, and the tendency of MSC peripheral vascular micro aggregates might synergize with the vascular clots of the COVID-19 disease process, causing significant central or peripheral vascular insufficiency. The second exosome therapeutic area for severe COVID-19 involves use of convalescent plasma for its content of acquired immune antibodies that must consider the role in this therapy of contained nearly trillions of exosomes. Many of these derive from activated immune modulating cells and likely can function to transfer miRNAs that acting epigenetically to also influence the convalescent plasma recipient response to the virus. There is sufficient evidence, like recovery of patients with antibody deficiencies, to postulate that the antibodies actually have little effect and that immune resistance is principally due to T cell mechanisms. Further, COVID-19 convalescent plasma has remarkably weak beneficial effects if compared to what was expected from many prior studies. This may be due to the dysfunctional immune response to the infection and resulting weak Ab that may be impaired further by antagonistic exosomes in the convalescent plasma. At the least, pre selection of plasma for the best antibodies and relevant exosomes would produce the most optimum therapy for very severely affected COVID-19 patients.
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Affiliation(s)
- Philip W. Askenase
- Section of Rheumatology and Clinical ImmunologyDepartment of Internal MedicineYale University School of MedicineNew HavenConnecticutUSA
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