Blood eosinophils,eosinophil-derived proteins,and leukotriene C4 generation in relation to bronchial hyperreactivity in children with atopic dermatitis

To assess the relation among eosinophil-related variables in the peripheral blood, bronchial hyperreactivity, and the presence of atopic dermatitis in children aged 5–14 years, we studied 11 patients with atopic dermatitis alone, six with asthma and atopic dermatitis, 12 with asthma alone, and 12 healthy controls. Eosinophil counts, levels of eosinophil cationic protein, and the capacity of eosinophils to generate leukotriene (LT) C₄, as well as bronchial hyperreactivity and a severity score for atopic dermatitis, were determined. Eosinophil variables were significantly higher in both patient groups with atopic dermatitis than in normal controls. In particular, ionophore A 23187 LTC₄ generation was higher in patients with atopic dermatitis alone (median 82, range 25–273 ng/10⁶ cells) and patients with combined asthma and atopic dermatitis (median 68, range 32–583 ng/10⁶ cells) than in normal controls (median 9, range 1–67 ng/10⁶ cells). However, there was no difference between the group of atopic dermatitis patients with asthma and without asthma. We conclude that eosinophil variables in the peripheral blood are mainly influenced by the presence of atopic dermatitis, and not the presence and the severity of asthma in patients with both asthma and atopic dermatitis.