Nasal eosinophilia as a noninvasive biomarker of type 2 inflammation and treatment response in children with asthma.

METHODS

A total of 202 children aged 7-18 years were included in the study and stratified according to the treatment type and fractional exhaled nitric oxide (FeNO) values. Absolute peripheral blood eosinophil counts, nasal eosinophil percentages, FeNO levels and age were assessed.

RESULTS

Antihistamines and leukotriene receptor antagonists were associated with a significant reduction in nasal eosinophilia (p = 0.004 and p = 0.001, respectively), whereas inhaled corticosteroids showed no significant effect (p = 0.928). A significant positive association was demonstrated between FeNO levels and nasal eosinophilia (p < 0.001), while age showed a significant negative effect (p < 0.001).

CONCLUSION

Nasal cytology may represent an easily applicable, and ethically acceptable tool for noninvasive monitoring local eosinophilic inflammation in pediatric asthma. Nasal eosinophilia appears to reflect dynamic airway inflammatory changes more directly than peripheral blood eosinophils and may be useful adjunctive marker for monitoring treatment-related changes and guiding personalized therapy.