Eosinophils and COVID‐19: Insights into immune complexity and vaccine safety

Abstract Background COVID‐19 exhibits a variety of symptoms and may lead to multi‐organ failure and death. This clinical complexity is exacerbated by significant immune dysregulation affecting nearly all cells of the innate and adaptive immune system. Granulocytes, including eosinophils, are affecte...

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Main Authors: Wided Sahli, Joana Vitte, Benoit Desnues
Format: Article
Language:English
Published: Wiley 2025-03-01
Series:Clinical and Translational Allergy
Subjects:
Online Access:https://doi.org/10.1002/clt2.70050
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author Wided Sahli
Joana Vitte
Benoit Desnues
author_facet Wided Sahli
Joana Vitte
Benoit Desnues
author_sort Wided Sahli
collection DOAJ
description Abstract Background COVID‐19 exhibits a variety of symptoms and may lead to multi‐organ failure and death. This clinical complexity is exacerbated by significant immune dysregulation affecting nearly all cells of the innate and adaptive immune system. Granulocytes, including eosinophils, are affected by SARS‐CoV‐2. Objectives Eosinophil responses remain poorly understood despite early recognition of eosinopenia as a hallmark feature of COVID‐19 severity. Results The heterogeneous nature of eosinophil responses categorizes them as dual‐function cells with contradictory effects. Eosinophil activation can suppress virus‐induced inflammation by releasing type 2 cytokines like IL‐13 and granular proteins with antiviral action such as eosinophil‐derived neurotoxins and eosinophil cationic protein, and also by acting as antigen‐presenting cells. In contrast, eosinophil accumulation in the lungs can induce tissue damage triggered by cytokines or hormones like IFN‐γ and leptin. Additionally, they can affect adaptive immune functions by interacting with T cells through direct formation of membrane complexes or soluble mediator action. Individuals with allergic disorders who have elevated levels of eosinophils in tissues and blood, such as asthma, do not appear to be at an increased risk of developing severe COVID‐19 following SARS‐CoV‐2 infection. However, the SARS‐CoV‐2 vaccine appears to be associated with complications and eosinophilic infiltrate‐induced immunopathogenicity, which can be mitigated by corticosteroid, anti‐histamines and anti‐IL‐5 therapy and avoided by modifying adjuvants or excipients. Conclusion This review highlights the importance of eosinophils in COVID‐19 and contributes to a better understanding of their role during natural infection and vaccination.
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spelling doaj-art-ac3d4817a05f4c608d780aa66d09ffa42025-08-20T03:44:00ZengWileyClinical and Translational Allergy2045-70222025-03-01153n/an/a10.1002/clt2.70050Eosinophils and COVID‐19: Insights into immune complexity and vaccine safetyWided Sahli0Joana Vitte1Benoit Desnues2Aix Marseille University MEPHI Marseille FranceLaboratory of Immunology University Hospital of Reims Reims FranceAix Marseille University MEPHI Marseille FranceAbstract Background COVID‐19 exhibits a variety of symptoms and may lead to multi‐organ failure and death. This clinical complexity is exacerbated by significant immune dysregulation affecting nearly all cells of the innate and adaptive immune system. Granulocytes, including eosinophils, are affected by SARS‐CoV‐2. Objectives Eosinophil responses remain poorly understood despite early recognition of eosinopenia as a hallmark feature of COVID‐19 severity. Results The heterogeneous nature of eosinophil responses categorizes them as dual‐function cells with contradictory effects. Eosinophil activation can suppress virus‐induced inflammation by releasing type 2 cytokines like IL‐13 and granular proteins with antiviral action such as eosinophil‐derived neurotoxins and eosinophil cationic protein, and also by acting as antigen‐presenting cells. In contrast, eosinophil accumulation in the lungs can induce tissue damage triggered by cytokines or hormones like IFN‐γ and leptin. Additionally, they can affect adaptive immune functions by interacting with T cells through direct formation of membrane complexes or soluble mediator action. Individuals with allergic disorders who have elevated levels of eosinophils in tissues and blood, such as asthma, do not appear to be at an increased risk of developing severe COVID‐19 following SARS‐CoV‐2 infection. However, the SARS‐CoV‐2 vaccine appears to be associated with complications and eosinophilic infiltrate‐induced immunopathogenicity, which can be mitigated by corticosteroid, anti‐histamines and anti‐IL‐5 therapy and avoided by modifying adjuvants or excipients. Conclusion This review highlights the importance of eosinophils in COVID‐19 and contributes to a better understanding of their role during natural infection and vaccination.https://doi.org/10.1002/clt2.70050COVID‐19eosinophilsinflammationribonucleasestissue infiltrationvaccination
spellingShingle Wided Sahli
Joana Vitte
Benoit Desnues
Eosinophils and COVID‐19: Insights into immune complexity and vaccine safety
Clinical and Translational Allergy
COVID‐19
eosinophils
inflammation
ribonucleases
tissue infiltration
vaccination
title Eosinophils and COVID‐19: Insights into immune complexity and vaccine safety
title_full Eosinophils and COVID‐19: Insights into immune complexity and vaccine safety
title_fullStr Eosinophils and COVID‐19: Insights into immune complexity and vaccine safety
title_full_unstemmed Eosinophils and COVID‐19: Insights into immune complexity and vaccine safety
title_short Eosinophils and COVID‐19: Insights into immune complexity and vaccine safety
title_sort eosinophils and covid 19 insights into immune complexity and vaccine safety
topic COVID‐19
eosinophils
inflammation
ribonucleases
tissue infiltration
vaccination
url https://doi.org/10.1002/clt2.70050
work_keys_str_mv AT widedsahli eosinophilsandcovid19insightsintoimmunecomplexityandvaccinesafety
AT joanavitte eosinophilsandcovid19insightsintoimmunecomplexityandvaccinesafety
AT benoitdesnues eosinophilsandcovid19insightsintoimmunecomplexityandvaccinesafety