Allergic sensitization to lipocalins reflects asthma morbidity in dog dander sensitized children.

Background: Sensitization to dog is an important risk factor for asthma in children, but the clinical relevance of IgE to available dog- and furry animal allergen molecules is uncertain.

Methods: Spirometry, methacholine challenge, fraction of exhaled nitric oxide, nasal challenge with dog extract and questionnaires were performed in 59 dog-sensitized children (age 10-18 years). Serum IgE to dog-, cat-, horse extracts and the allergen molecules Can f 1-6, Fel d 1, Fel d 2, Fel d 4 and Equ c 1 were evaluated.

Results: Median numbers of positive IgE results to furry animal allergen molecules among children without asthma was 3, with asthma 5.5 and with troublesome asthma 9 (asthma vs. no asthma;  = 0.039; troublesome asthma vs. no asthma;  = 0.009). The odds ratio for asthma if sensitized to any lipocalin was 7.2 (95% confidence Interval: 1.44-35.9). Children with troublesome asthma had higher IgE levels to the lipocalins Can f 2, Can f 4 and Can f 6 compared to the rest of the study population (44 vs. 4.1 kU/L,  = 0.015; 5.8 vs. 0.9 kU/L,  = 0.018 and 1.3 vs. 0.7 kU/L,  = 0.03 respectively). Furthermore, a positive nasal challenge was more common among children with troublesome asthma (83% vs. 36%,  = 0.036).

Conclusions: Polysensitization to furry animal allergens and lipocalins is associated with asthma in dog-sensitized children. Children with troublesome asthma have higher IgE levels to several dog lipocalins than other dog sensitized children.

Key Message: Polysensitization to furry animal allergens and high IgE levels to the dog lipocalins Can f 2, Can f 4 and Can f 6 is associated with asthma severity in dog dander sensitized children. Molecular allergy diagnostics may thus help the clinicians to evaluate the impact of allergic sensitization on asthma morbidity.