Sarzsinszky E, et al. Allergy Asthma Immunol Res. 2021 Jan;13(1):154-163. https://doi.org/10.4168/aair.2021.13.1.154

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.

Allergen sensitization profiles are increasingly affected by environmental and climate changes. This study exemplifies fundamental differences in molecular IgE sensitization profiles in two nearby regions in Argentina with different climatic conditions (La Plata and Bahía Blanca). A cross-sectional study was conducted involving 155 patients with allergic symptoms from La Plata and Bahía Blanca (34.0 ± 11.2 years, female/male: 83/72). Serum samples were analyzed for IgE reactivity using a chip containing 101 micro-arrayed allergen molecules. Statistical analyses were performed to compare allergen-specific IgE levels, sensitization prevalences and reported symptoms. Patients from La Plata—with subtropical weather—showed a higher prevalence of IgE reactivity to house dust mite (HDM) allergens (Der p 23: 74%; Der p 1: 53% and Der p 2: 56%) and more frequently reported asthma (AS) symptoms (40% vs. 24%) than patients from Bahía Blanca. In contrast, patients from Bahía Blanca, with dry and windy weather, exhibited higher sensitization rates to pollen allergens, particularly Phl p 1 (49%) and Ole e 1 (22%) as well as to Alternaria alternata (Alt a 1, 35%) and reported a significantly higher prevalence of skin manifestations (54% vs. 31%) than those from La Plata. Cat allergen Fel d 1 was an equally important sensitizer in both regions (La Plata 30% and Bahía Blanca 37%). Sensitization to class 1 food allergens was rare in both groups (1–8%), including non-specific lipid transfer proteins (peanut Ara h 9 and peach Pru p 3) but IgE sensitizations to genuine peanut allergens were almost absent. Important regional differences in allergen sensitization profiles were observed between two geographically close regions with different climatic conditions. Our findings underscore the relevance of region-specific allergen profiling and highlight the clinical utility of molecular allergy diagnosis for a more precise allergen identification and improved management of allergic diseases.