Related Experiment Videos
Desensitisation of neutrophil responses by systemic interleukin 8 in cystic fibrosis
1University of Southampton, UK.
Insights
Neutrophils from children with cystic fibrosis show reduced response to interleukin 8 (IL-8) due to fewer IL-8 receptors. This desensitization is linked to high systemic IL-8 levels, impacting neutrophil function in cystic fibrosis patients.
Area of Science:
- Immunology
- Pediatrics
- Respiratory Medicine
Background:
- Neutrophil infiltration and inflammation are hallmarks of pediatric cystic fibrosis.
- Interleukin 8 (IL-8), a key neutrophil chemoattractant, is implicated in cystic fibrosis pathology.
- Elevated IL-8 levels are observed in sputum and bronchoalveolar lavage fluid of children with cystic fibrosis.
Purpose of the Study:
- To compare IL-8 induced neutrophil chemotaxis in children with cystic fibrosis versus healthy controls.
- To quantify the number of IL-8 receptors on neutrophils from both groups.
Main Methods:
- Neutrophils were isolated from 18 cystic fibrosis patients and 13 controls.
- Chemotaxis was assessed using multiwell microchemotaxis chambers.
- IL-8 receptor expression was determined by Scatchard analysis of radiolabeled IL-8 binding.
Main Results:
- Neutrophil migration to IL-8 was reduced in cystic fibrosis patients at lower concentrations.
- Neutrophils from cystic fibrosis patients had significantly fewer IL-8 receptors (22,000/cell) compared to controls (75,000/cell).
Conclusions:
- Neutrophils from cystic fibrosis patients exhibit reduced responsiveness to IL-8.
- This diminished response is attributed to receptor desensitization from chronic exposure to high IL-8 levels.
- Understanding IL-8 receptor dynamics is crucial for managing cystic fibrosis-related inflammation.
Background:
Inflammation associated with neutrophil infiltration is a commonly observed feature of children with cystic fibrosis. Production of the major neutrophil chemotactic cytokine interleukin 8 (IL-8) is potentially of great importance in the pathology of cystic fibrosis. Concentrations of IL-8 in both sputum and bronchoalveolar lavage fluid have been found to be higher in children with cystic fibrosis than in controls. The IL-8 induced chemotactic response and numbers of IL-8 receptors on peripheral neutrophils obtained from children with cystic fibrosis have been compared with a control group of children.
Methods:
Cells were isolated from 18 patients with cystic fibrosis (aged 4-20 years) and 13 controls (aged 5-12 years) by dextran centrifugation followed by separation on Lymphoprep. Chemotaxis was assayed using multiwell microchemotaxis chambers and 5 microns polycarbonate filters. Filters were fixed and stained with Haema-Gurr for counting. Results were expressed as numbers of neutrophils per high power field (HPF).
Results:
At the optimum concentration (1 x 10(-8) mol/l) the number of cells migrating were similar for controls (150 (12)/HPF) and for the cystic fibrosis group (140 (14)/HPF)). At lower concentrations the numbers of neutrophils migrating were lower for the cystic fibrosis group. Scatchard analysis of 125I-labelled IL-8 binding revealed lower numbers of receptors on neutrophils from patients with cystic fibrosis (22,000 per cell) than from controls (75,000 per cell).
Conclusions:
Reduced responsiveness to IL-8 of neutrophils from patients with cystic fibrosis is associated with receptor desensitisation as a result of exposure to high systemic levels of IL-8.