Study Population
Subjects in this study included pediatric patients recruited from outpatient clinics in the Stockholm area as previously described26. Consent was obtained from parents of each study subject. Briefly, children ages 10 to 18 years were recruited and sensitization to dog dander was confirmed by either positive skin prick test response (wheal size > 3 mm), serum IgE to dog dander > 0.10 kUA/L, or both. Allergen-sensitized subjects were included regardless of a history of clinical allergy symptoms to dog dander. Subjects with impaired lung function due to any cause other than asthma and any completed or current allergen-specific immunotherapy to furry animals were excluded from the study. Sixty (60) allergen-sensitized children were included in the study group, and a further 17 non-sensitized children without current symptoms of airway allergy were included in the control group. All subjects underwent venous blood sampling for preparation of serum, clinical history and physical examination, dynamic spirometry, and methacholine bronchoprovocation. Clinical characteristics are summarized in Table 1.