Value of Component Resolved Diagnostics to Aspergillus fumigatus in Patients with Upper Airway Complaints

Introduction: Sensitization to Aspergillus fumigatus is a risk factor for severe asthma. However, little is known about its presence, appearance, and impact on allergic rhinitis. Herein, we investigated the usefulness of component resolved diagnostics in patients sensitized to Aspergillus fumigatus protein extract. Methods: Seventy-eight patients with suspected allergic rhinitis and elevated IgE levels toward Aspergillus fumigatus protein extract were retrospectively evaluated regarding their total and Aspergillus-specific IgE levels and their skin prick test. Furthermore, they were tested for specific IgE antibodies against Asp f 1, 2, 3, 4, and 6. Results: Skin prick test missed 6 patients (7.7%) with elevated IgE toward Aspergillus fumigatus protein extract. Fifty percent of patients (n = 39) were sensitized to at least one component. Even though monosensitization affected all components, all patients with positivity toward more than one component were sensitized to Asp f 1. There was a statistically significant increase of Aspergillus-specific IgE with increasing number of components affected by sensitization. Many patients were oligo- (34.6%) or polysensitized (51.3%). There was a high prevalence of sinusitis (61.8%). Conclusions: Component resolved diagnostic testing toward the major allergen Asp f 1 was less sensitive than skin prick test and serology to Aspergillus fumigatus protein extract. However, sensitivity of component resolved diagnostics might be underestimated. Diagnostics of the species-specific allergens Asp f 1, 2, and 4 might allow to differentiate between genuine and cross-reactive sensitization. In the clinical routine, skin prick test and serology to crude extract remain the methods of choice.