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Quantitation of inflammatory responses to bacteria in young cystic fibrosis and control patients
M S Muhlebach1, P W Stewart, M W Leigh
1Division of Pulmonary Medicine and Allergy, Department of Pediatrics, Center for Environmental Medicine and Lung Biology, The University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA.
Insights
Children with cystic fibrosis (CF) show heightened inflammatory responses to bacterial lung infections compared to other respiratory conditions. This suggests early anti-inflammatory therapy may benefit CF patients.
Area of Science:
- Pulmonology
- Immunology
- Pediatrics
Background:
- Inflammation is implicated in cystic fibrosis (CF) lung disease pathogenesis.
- Understanding the inflammatory response to infection in CF is crucial for treatment.
Purpose of the Study:
- To quantitatively compare bronchoalveolar lavage fluid (BALF) inflammation in children with CF versus those with other chronic respiratory problems.
- To assess the relationship between inflammation and bacterial infection in BALF.
Main Methods:
- Collected BALF from 54 CF patients and 55 controls undergoing bronchoscopy.
- Performed differential cell counts, measured interleukin-8 (IL-8), and conducted quantitative bacterial cultures.
- Analyzed the ratio of neutrophils and IL-8 to bacteria, and used linear regression to model inflammation as a function of bacterial load.
Main Results:
- CF patients exhibited a significantly higher ratio of neutrophils or IL-8 to bacteria compared to controls, irrespective of the specific pathogen.
- Infection with Pseudomonas aeruginosa in CF patients did not correlate with increased inflammation compared to other infections.
- Linear regression showed a positive correlation between bacterial quantity and inflammation markers (neutrophils, IL-8) in both groups, but with significantly higher levels in CF patients.
Conclusions:
- The inflammatory response to bacterial infection is amplified or prolonged in children with CF.
- This heightened inflammation is not solely attributable to CF-specific pathogens like P. aeruginosa.
- Findings support the potential benefit of early anti-inflammatory interventions in managing CF lung disease.
Abstract:
Recent studies suggest that inflammation plays a role in the pathogenesis of lung disease in cystic fibrosis (CF). The goal of the present study was to quantitatively compare bronchoalveolar lavage fluid (BALF) inflammation and its relation to bacterial infection, between children with CF and children with other chronic respiratory problems. Differential cell counts, immunoreactive interleukin 8 (IL-8), and quantitative bacterial cultures were done in BALF from 54 CF (median age 1.8 yr) and 55 control patients (median age 1.0 yr) who underwent bronchoscopy for clinical indications. Among infected CF patients, those with Pseudomonas aeruginosa did not have more inflammation than those without P. aeruginosa. The ratio of neutrophils or of IL-8 to bacteria in BALF was significantly greater for CF patients compared with control subjects, regardless of pathogen. Calculation of linear regression for either neutrophils or IL-8, as a function of bacterial quantity, yielded positive slopes for both CF and control patients, but with significant elevations for CF. We conclude that the inflammatory response to bacterial infection is increased or prolonged in CF compared with control patients, and that this increase is not necessarily due to pathogens specific for CF (e.g., P. aeruginosa). These data may provide further rationale for anti-inflammatory therapy early in CF.
