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Published on: July 28, 2016
Enhanced superoxide generation by eosinophils from asthmatic children
U Schauer1, C Leinhaas, R Jäger
1Children's Hospital, University of Marburg, FRG.
Insights
Asthmatic children show heightened eosinophil superoxide generation, suggesting these cells may be primed in vivo. This increased activity was not further enhanced by common stimulants, unlike in healthy controls.
Area of Science:
- Immunology
- Pediatrics
- Respiratory Medicine
Background:
- Eosinophils and neutrophils are key immune cells involved in inflammatory responses.
- Asthma is a chronic respiratory disease characterized by airway inflammation and hyperresponsiveness.
- Superoxide generation by phagocytes is a critical component of the inflammatory cascade.
Purpose of the Study:
- To investigate differences in superoxide generation between eosinophils and neutrophils from asthmatic children and healthy controls.
- To explore the priming potential of specific inflammatory mediators on these cells in asthma.
Main Methods:
- Purified peripheral blood eosinophils and neutrophils were isolated from 21 asthmatic children and 11 age-matched healthy controls.
- Cells were stimulated with phorbol myristate acetate to measure superoxide generation via cytochrome c reduction.
- Cells were preincubated with granulocyte-macrophage colony-stimulating factor and platelet-activating factor to assess priming effects.
Main Results:
- Eosinophils from asthmatic children exhibited significantly higher superoxide generation compared to neutrophils from the same patients and cells from healthy controls.
- Preincubation with granulocyte-macrophage colony-stimulating factor or platelet-activating factor augmented superoxide generation in control eosinophils but not in asthmatic eosinophils.
- Neutrophils from both asthmatic and control children showed similar superoxide generation levels.
Conclusions:
- Asthmatic children's eosinophils display enhanced superoxide generation, indicative of a potential in vivo priming state.
- The diminished response to priming agents in asthmatic eosinophils suggests they are already maximally activated or desensitized.
- These findings highlight the role of eosinophils in asthma pathogenesis and suggest altered cellular responsiveness in affected children.
Abstract:
In 21 asthmatic children, aged 2-19 years, and 11 age-matched controls purified (purity greater than 75%) peripheral blood eosinophils and neutrophils (purity greater than 95%) were stimulated with phorbol myristate acetate (44 ng/ml) for 30 min at 37 degrees C. The superoxide generation was determined as well as the superoxide dismutase inhibitable cytochrome c reduction. Eosinophils obtained from asthmatic patients displayed a significantly higher O2- generation (p less than 0.01) when compared to neutrophils from the same patients or to eosinophils and neutrophils from healthy controls. Preincubation with human recombinant granulocyte macrophage colony stimulating factor for 30 min or platelet-activating factor for 10 min resulted in augmented O2- generation by eosinophils from control, but not from asthmatic children, indicating a possible in vivo priming of eosinophils in asthma.
