Severe childhood asthma and allergy to furry animals: refined assessment using molecular-based allergy diagnostics

Abstract

Background: Allergy to cats and dogs and polysensitization towards these animals are associated with severe childhood asthma. Molecular-based allergy diagnostics offers new opportunities for improved characterization and has been suggested to be particularly useful in patients with polysensitization and/or severe asthma. The aim was to use extract- and molecular-based allergy diagnostics to compare patterns of IgE sensitization towards aeroallergens in children with problematic severe and controlled asthma.

Methods: Children with a positive ImmunoCAP towards any furry animal (cat, dog or horse) were recruited from a Nationwide Swedish study on severe childhood asthma. Severe (n = 37, age 13 years) and controlled (n = 28, age 14 years) asthmatics underwent assessment of allergic sensitization by ImmunoCap (kUA /l) and immunosolid-phase allergen chip (ISAC). In addition, Asthma Control Test, spirometry and a methacholine challenge were performed.

Results: Children with severe asthma had lower asthma control (p < 0.001) and FEV1 (p = 0.001) and more bronchial hyper-responsiveness (p = 0.008) in spite of high doses of inhaled steroids (≥800 μg budesonide). Children with severe asthma displayed higher levels of IgE antibodies towards cat (17 vs. 3.9, p = 0.027), dog (3.8 vs. 1.2, p = 0.012) and horse (7.4 vs. 0.7, p = 0.014). Sensitization towards Can f 2 (22% vs. 0%, p = 0.009) and Equ c 1 (51% vs. 25%, p = 0.03) was more common in severe asthma. IgE levels towards Equ c 1 correlated with asthma control (r = -0.41, p = 0.04).

Conclusion: Children with severe allergic asthma had higher sIgE levels to cat, dog and horse. Molecular-based allergy diagnostics revealed a more complex molecular spreading of allergen components in children with the most severe disease.

Keywords: allergy; children; furry animals; molecular-based allergy diagnostics; severe asthma.