Age-related molecular IgE sensitization to indoor and outdoor respiratory allergens: a two-step cross-sectional study in Algeria and Türkiye.

BACKGROUND: Immunoglobulin E-mediated allergy is the most important hypersensitivity disease affecting more than 30% of the population worldwide. The analysis of molecular IgE sensitization profiles in defined populations and age groups is important for the development of allergen-specific preventive and therapeutic interventions. The present study was performed to examine if there are differences regarding molecular IgE reactivity profiles in children and adults from two regions with similar climate and exposome.

METHODS: This two-step cross-sectional study assessed molecular IgE reactivity profiles using an experimental allergen microarray comprising 105 allergen molecules. In the first step, an exploratory cross-sectional study, serum samples from 539 allergic patients (259 children, 280 adults) who were born and grew up in the Algiers region were analyzed. The second step was a prospective cross-sectional study performed in 272 Turkish allergic patients (133 children, 139 adults) from Istanbul and Samsun regions with a climate and allergen exposome similar to Algiers, with the goal of investigating the reproducibility of possible differences in molecular IgE sensitization profiles between children and adults.

FINDINGS: In both the exploratory Algiers study and the prospective Turkish study, significantly more children than adults with respiratory allergy were sensitized to major respiratory house dust mite allergens (Algiers: Der p 1, Der p 2: p < 0.001 and Der p 23: p = 0.001; Türkiye: Der p 1: p = 0.018 and Der p 2: p = 0.019) whereas significantly more adults than children were sensitized to regionally common respiratory outdoor allergens (Algiers: Ole e 1: p = 0.037; Phl p 1: p = 0.046; Türkiye: Ole e 1: p = 0.016; Amb a 1: p = 0.002; Amb a 8: p < 0.001). Asthma was significantly more common in children than in adult patients with respiratory allergy (Algiers: p < 0.001; Türkiye: p = 0.034).

INTERPRETATION: Our study demonstrates different molecular IgE sensitization profiles in two age groups (children and adults) on two different continents with a similar climate and allergen exposome which may be due to exogenous factors such as climate change, different lifestyles, pollution and changes in vegetation. Both major house dust mite sensitization and asthma were more common in children, suggesting sensitization profile may contribute to asthma risk.

FUNDING: Danube Allergy Research Cluster, Country of Lower Austria, Medical University of Vienna and Russian Science Foundation.