Influence of allergen avoidance on the eosinophil phase of airway inflammation in children with allergic asthma.

BACKGROUND

Exposure to relevant allergens causes an increase in bronchial hyperresponsiveness, as well as an inflammatory reaction at the site of the bronchial mucosa in patients with asthma.

OBJECTIVE

The purpose of this study was to determine whether antigen avoidance can exert an antiinflammatory effect on the eosinophil phase of airway inflammation in children with asthma.

METHODS

The level of bronchial hyperreactivity and the percentage of eosinophils in sputum samples obtained by inhalation of hypertonic saline solution, were evaluated in a group of asthmatic children allergic to house dust mite before and after a period of antigen avoidance in an Alpine environment (1756 m).

RESULTS

At the end of the avoidance period PC20 increased from a median value (lower and upper quartile: Q1, Q3) of 1.17 (0.74, 4.75) to 3.5 (1.18, 8.87) mg/ml (p = 0.02), and eosinophil percentage in the sputum decreased from a median value (Q1, Q3) of 14.02 (3.34, 28.24) to 2.08 (0, 7.4) (p less than 0.01).

CONCLUSION

A 3-month period of antigen avoidance can significantly reduce the eosinophil phase of airway inflammation, along with bronchial hyperresponsiveness, in patients with asthma.