Microarrayed Allergen Molecules Distinguish IgE Sensitisation to Blomia tropicalis and Dermatophagoides pteronyssinus

BACKGROUND: House dust mites (HDMs) are the most important respiratory allergen sources. In temperate regions, the genus Dermatophagoides predominates, whereas in sub-tropical and tropical regions, the genus Blomia is also of high importance. There is only limited IgE cross-reactivity between Dermatophagoides and Blomia. OBJECTIVE: To produce a chip containing purified microarrayed Blomia tropicalis (Blo t) and Dermatophagoides pteronyssinus allergens (Der p) capable of identifying patients with a genuine Blo t or Der p IgE sensitisation, co-sensitisation and/or cross-sensitisation. METHODS: Chips containing seven purified Blo t and thirteen Der p allergens were generated by microarray technology and tested for IgE and IgG reactivity in HDM-sensitised patients from Blo t-endemic (group 1: n = 115) and Blo t-non-endemic (group 2: n = 33) regions. IgE cross-reactivity was analysed by IgE inhibition studies. RESULTS: IgE levels to Blo t 2, Blo t 5, Blo t 10, Blo t 12 and Blo t 21 were significantly higher in HDM-sensitised patients from Blo t-endemic as compared to patients from Blo t-non-endemic regions, whereas the opposite was observed for IgE to Der p 2 and Der p 21 in patients from Blo t-non-endemic regions. An algorithm based on IgE reactivity profiles and allergen-specific IgE levels capable of discriminating genuine sensitisation to Blo t and Der p or co-sensitisation was established. In HDM-sensitised patients from Blo t-endemic regions, each of the aforementioned sensitisation profiles was observed, whereas in HDM-sensitised patients from Blo t-non-endemic regions, only genuine sensitisations to Der p and co-sensitisations to Blo t and Der p were observed. CONCLUSION: The algorithm based on microarrayed Blo t and Der p allergens for discrimination of Blo t and Der p sensitisation may support prescription of allergen-specific immunotherapy. At minimum, it will be helpful in understanding disease aetiology and for fine resolution mapping of allergic reactivities in HDM sensitisation.