Real-Life Study for the Diagnosis of House Dust Mite Allergy - The Value of Recombinant Allergen-Based IgE Serology

Abstract

Background:Dermatophagoides pteronyssinus is one of the most important perennial allergen sources worldwide. Molecular diagnostics using the commercially available major allergens (Der p 1 and Der p 2) in combination with Der p 10 do not detect house dust mite (HDM) sensitization in a number of cases when used alone. The objective was to evaluate the IgE reactivity profiles of these patients using an experimental immunoassay biochip. Methods: Sera of HDM-allergic patients (positive skin prick test, CAP class ≥1 for allergen extract, and positive intranasal provocation) were tested for IgE antibodies against Der p 1, Der p 2, and Der p 10 by ImmunoCAP fluorescence enzyme immunoassay. Negatively tested sera were examined by an experimental chip containing 13 microarrayed HDM allergens. Results: Of 97 patients tested, 16 showed negative results to Der p 1, Der p 2, and Der p 10. MeDALL chip evaluation revealed 5 patients monosensitized to Der p 23, and 11 patients were negative for all HDM MeDALL chip components. Seven sera were available for further testing, and 3 of them showed IgE reactivity to dot-blotted nDer p 1, and 2 reacted with high-molecular weight components (>100 kDa) in nitrocellulose-blotted HDM extract when tested with ¹²⁵I-labeled anti-IgE in a RAST-based assay. The HDM extract-specific IgE levels of the 11 patients were <3.9 kU/l. Conclusions: Recombinant allergen-based IgE serology is of great value when conventional IgE diagnostics fails. Der p 23 is an important HDM allergen, especially when major allergens are negative. Therefore, it would be desirable to have Der p 23 commercially available. Further research concerning the prevalence and clinical significance of different HDM allergens is needed.

Greater Real-Life Diagnostic Efficacy of Allergen Molecule-Based Diagnosis for Prescription of Immunotherapy in an Area with Multiple Pollen Exposure

“…Efficient diagnostic guidelines leading to appropriate treatment are therefore urgently needed. Several studies have shown that allergen molecule-based diagnosis is more precise in identifying the sensitizing allergen sources [19,20,21,22,23] and that it is possible to select allergens for AIT more precisely according to component-resolved diagnosis with allergen molecules than based on diagnosis with allergen extracts [10,11]. However, to the best of our knowledge, our study is the first to investigate in a real-life setting whether allergen molecule-based testing is more cost-effective in selecting the correct AIT vaccines than conventional allergy diagnosis based on SPT with allergen extracts.…”

Allergens of <b><i>Blomia tropicalis</i></b>: An Overview of Recombinant Molecules

“…These proteins are registered in the allergen database (www.allergen.org) and summarized in Table 1. These developments were enabled by the application of recombinant DNA technology, which opened up new possibilities for the field of allergy, leading not only to the production of purified recombinant house dust mite allergens but also to the standardization of molecule-based preparations for diagnosis and allergen-specific immunotherapy [20]. Since the first data of a purified recombinant B. tropicalis allergen (rBlo t 5) published in 1995 by Arruda et al [21], several research groups have produced B. tropicalis allergens in recombinant form using different expression systems [12,22,23,24,25].…”

Mite allergens

“…Information about a detailed allergenicity evaluation is currently available for only 10% of all IgE binding proteins in the databases. Completing this task will allow a better assessment of the pathogenic role of each mite allergen as has been recently suggested for Der p 23 [17,18] and could be great independently of its IgE-binding frequency [19][20][21]. Recognizing that regional combinations of mite allergens are more appropriate and less expensive than large panels of just IgE-binding components will also help.…”

“…There are a number of mite IgE-binding components available for CDR, including species-specific and cross-reacting molecules, most of them with well-defined structural and epitope data, although not all with empirically demonstrated allergenicity. A necessary step, the determination of the IgE reactivity against mite components in different populations and environments, has partially accomplished [16][17][18]. However, the analyses of these data have been based on the frequency of IgE reactivity, not including other aspects of allergenicity.…”