Mold Sensitization in Asthmatic and Non-asthmatic Subjects Diagnosed with Extract-Based Versus Component-Based Allergens

Asthmatic patients are suspected of having a higher risk of mold sensitization. Thus, precise diagnosis of fungal sensitization is important. Mold allergen extracts are difficult to standardize, but component-resolved allergy diagnosis may be an alternative to replace extract-based tests. In this research, asthmatic and non-asthmatic subjects were studied for their sensitization to Aspergillus fumigatus (Asp f), Cladosporium herbarum (Cla h), Penicillium chrysogenum (Pen ch), Alternaria alternata (Alt a), and Aspergillus versicolor (Asp v). Extract-based tests were applied using the skin prick test (SPT) and allergen-specific immunoglobulin E (sIgE). Subjects with extract-based sensitization to Asp f or Alt a were further investigated for sIgE response to recombinant (r) single mold allergens. At least one mold sensitization was found in about 50% of asthmatic and non-asthmatics with the most frequent sensitization to Alt a, followed by Pen ch, Asp f, Cla h, and Asp v. Interestingly, sensitization rate to individual mold species was always higher in asthmatics and was only significant for Pen ch. The component-resolved diagnosis with the sum of rAsp f 1 - rAsp f 4 plus rAsp f 6 matched the extract-based results (SPT and/or sIgE) in 50% of asthmatics and 46% of non-asthmatics, whereas, rAlt a 1 covered 59% of asthmatics and 50% non-asthmatics of extract-based Alt a sensitization. In conclusion, individual fungal sensitization rate was higher in asthmatics compared to non-asthmatics. Extract-based tests, especially SPTs, were most sensitive, but component-based tests covered 80% of extract-based serological sensitization to Alternaria and Aspergillus.