- D3.519 - Post-COVID-19 Reshaping of Molecular IgE Sensitization Profiles to Seasonal and Indoor Allergens

Post-viral immune dysregulation following SARS-CoV-2 infection has been suggested to influence allergic diseases; however, data on its impact on molecular IgE sensitization profiles remain limited. In particular, evidence regarding post-COVID-19 changes in cumulative IgE burden and the redistribution of IgE responses between seasonal and indoor allergen sources in patients with respiratory allergy is scarce.

Component-resolved IgE profiles to seasonal pollen and indoor/animal allergens were analyzed using the ALEX² microarray in 25 patients with respiratory allergy. Individual IgE profiles obtained before and four years after confirmed COVID-19 infection were compared. Patients were recruited at the International Allergy Center, Tashkent. Changes in molecular breadth, cumulative IgE levels, and median group trends were evaluated.

Following COVID-19, an expansion of molecular IgE sensitization was observed, characterized by the appearance of de novo IgE to multiple allergen components. A significant increase and/or de novo IgE sensitization was detected for panallergens, including profilins (Bet v 2, Phl p 12), polcalcins (Phl p 7, Aln g 4), PR-10 allergens (Bet v 1, Aln g 1, Cor a 1), and nsLTPs (Art v 3, Par j 2). In contrast, IgE profiles to major allergen molecules remained stable in the majority of cases. Despite increased molecular diversity, the cumulative IgE load to seasonal allergens consistently decreased at the median level. Conversely, indoor allergen sensitization demonstrated a marked quantitative amplification, with an approximately fivefold increase in median cumulative IgE levels. This increase was predominantly driven by animal-derived lipocalins (9/25 patients), major mold allergens (7/25), and major house dust mite and cockroach allergens (6/25). These changes were independent of seasonal allergen exposure and reflected qualitative immune reshaping rather than a global increase in IgE production. 

COVID-19 is associated with a redistribution of IgE responses characterized by attenuation of cumulative IgE to seasonal allergens despite increased molecular diversity, alongside a pronounced shift toward indoor allergen dominance. These findings suggest post-viral reprogramming of IgE memory and barrier immunity, supporting a model of virus-induced immune ecological imbalance. Component-resolved diagnostics are essential for capturing these complex post-infectious IgE dynamics.