Infection and inflammation in induced sputum from preschool children with chronic airways diseases

Area of Science:

• Pediatric Pulmonology
• Respiratory Medicine
• Clinical Diagnostics

Background:

• Airway inflammation and infection are common in preschool children with respiratory diseases.
• Non-invasive methods like induced sputum (IS) and peripheral blood eosinophilia are explored for detecting airway inflammation and infection.
• Comparison with broncho-alveolar lavage (BAL) is crucial for validating these non-invasive techniques.

Purpose of the Study:

• To evaluate the utility of induced sputum (IS) for detecting airway inflammation and infection in preschool children.
• To compare the diagnostic accuracy of IS with broncho-alveolar lavage (BAL).
• To assess the role of peripheral blood eosinophilia as a marker for lower airway inflammation.

Main Methods:

• Induced sputum (IS) was performed on preschool children with conditions like cystic fibrosis, recurrent wheeze, or wet cough.
• Sputum samples were analyzed for cytology, bacterial culture, and viral detection via PCR.
• Results were compared to broncho-alveolar lavage (BAL) in a subgroup of patients undergoing bronchoscopy.

Main Results:

• Induced sputum (IS) was successfully obtained from most preschool children without adverse events.
• IS and BAL culture results for bacteria and viruses showed agreement in approximately two-thirds of cases.
• Airway inflammation was measurable in only one-third of IS samples, which were predominantly neutrophilic, unlike BAL samples that showed higher eosinophilia. Peripheral blood eosinophilia correlated positively with BAL eosinophilia.

Conclusions:

• Induced sputum (IS) is a viable method for assessing respiratory infections in preschool children.
• IS is less sensitive than BAL for detecting airway inflammation, with predominantly neutrophilic findings.
• Peripheral blood eosinophil counts may serve as a more reliable indicator of lower airway eosinophilia in this pediatric population.