Eosinophils capture viruses, a capacity that is defective in asthma

Allergy. 2019 Oct;74(10):1898-1909. doi: 10.1111/all.13802. Epub 2019 May 15.


Background: Activated eosinophils cause major pathology in stable and exacerbating asthma; however, they can also display protective properties like an extracellular antiviral activity. Initial murine studies led us to further explore a potential intracellular antiviral activity by eosinophils.

Methods: To follow eosinophil-virus interaction, respiratory syncytial virus (RSV) and influenza virus were labeled with a fluorescent lipophilic dye (DiD). Interactions with eosinophils were visualized by confocal microscopy, electron microscopy, and flow cytometry. Eosinophil activation was assessed by both flow cytometry and ELISA. In a separate study, eosinophils were depleted in asthma patients using anti-IL-5 (mepolizumab), followed by a challenge with rhinovirus-16 (RV16).

Results: DiD-RSV and DiD-influenza rapidly adhered to human eosinophils and were internalized and inactivated (95% in ≤ 2 hours) as reflected by a reduced replication in epithelial cells. The capacity of eosinophils to capture virus was reduced up to 75% with increasing severity of asthma. Eosinophils were activated by virus in vitro and in vivo. In vivo this correlated with virus-induced loss of asthma control.

Conclusions: This previously unrecognized and in asthma attenuated antiviral property provides a new perspective to eosinophils in asthma. This is indicative of an imbalance between protective and cytotoxic properties by eosinophils that may underlie asthma exacerbations.

Keywords: CD69; RSV; exacerbation; influenza; rhinovirus_16.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, CD / metabolism
  • Antigens, Differentiation, T-Lymphocyte / metabolism
  • Asthma / diagnosis
  • Asthma / etiology*
  • Asthma / metabolism
  • Disease Models, Animal
  • Eosinophils / metabolism*
  • Eosinophils / pathology
  • Eosinophils / ultrastructure
  • Humans
  • Influenza A virus / physiology
  • Lectins, C-Type / metabolism
  • Lung / immunology
  • Lung / metabolism
  • Lung / pathology
  • Mice
  • Mice, Transgenic
  • Respiratory Function Tests
  • Virus Diseases / complications*
  • Virus Diseases / virology*


  • Antigens, CD
  • Antigens, Differentiation, T-Lymphocyte
  • CD69 antigen
  • Lectins, C-Type