CC chemokine receptor expression in childhood asthma is influenced by natural allergen exposure

Chemokines and their receptors may play an important role for leukocyte trafficking in allergic inflammation. Aim was to evaluate whether expression of chemokine receptors CCR4 and CCR8 on cells obtained by sputum induction from asthmatic allergic children may be influenced by house dust mite (HDM) allergen natural exposure. Twenty-one children (7-13 yr) with moderate asthma and sensitized to HDM were evaluated during a prolonged period of allergen avoidance (T0) and after a period of natural allergen exposure (T1). At each time point of sputum induction, lung function evaluation, exhaled nitric oxide (eNO) measurements were performed. At T1, CCR4 and CCR8 expression on sputum-induced cells increased from 28.4% +/- 2.9% and 25.8% +/- 1.9%, to 41.1% +/- 4.2% and 37.5% +/- 2.0%, respectively (p < 0.05 and p = 0.01). After allergen exposure, both sputum eosinophils (from 5.2% +/- 2.0% to 12.1% +/- 4.1%, p < 0.01) and eNO (from 15.1 +/- 2.2 ppb to 24.2 +/- 5.8 ppb, p < 0.05) showed significant increase. Lung function tests presented significant deterioration of Forced Expiratory Flow at 25-75% of Vital Capacity (FEF25--75) (p < 0.05) and increase of residual volume (p = 0.002). Significant changes in CC chemokine receptor expression in sputum-induced cells in asthmatic children in response to HDM exposure have been observed leading to consider the relevance of CCR4 and CCR8 in allergic asthmatic inflammation.