D2.95 - Comparative Molecular IgE Sensitization Patterns Across Developmental Stages: A Cross-Sectional Study in Clinical Cohorts from Ankara and Tehran

The macro-exposome, comprising biodiversity, climate, and lifestyle factors, plays a pivotal role in shaping IgE sensitization profiles across developmental stages. Molecular allergen diagnostics have revolutionized our understanding by enabling the characterization of sensitization patterns beyond traditional extract-based testing, allowing for the critical distinction between genuine primary sensitization and cross-reactivity. This study aimed to compare molecular allergen sensitization patterns between Ankara (Türkiye) and Tehran (Iran) to gain insight into how local environmental and cultural factors influence population-level allergy profiles.

This cross-sectional comparative study evaluated molecular allergen profiles in patients from Ankara and Tehran utilizing the ALEX² (Allergen Explorer) macroarray. Sensitization was defined as an IgE titer >0.3 kU_A/L. The study focused on characterizing the sensitization series across four age-defined cohorts: infants (0–1 year), preschool (2–5 years), school-age (6–12 years), and adolescents (13–18 years). The analysis accounted for the specific clinical utility of the test in each center—targeted diagnostic use in Ankara versus broader descriptive use in Tehran—to describe the evolution of sensitization patterns rather than absolute population prevalence.

The study included 1,384 patients from Türkiye and 1,901 from Iran (proportion of males: 63.5% vs. 75.3%; median age: 5 vs. 6 years). Among infants (0–1 year), the most frequent sensitizations in Türkiye vs. Iran were tree nuts (66.7% vs. 29.1%), egg (44.4% vs. 19.0%), and milk (36.7% vs. 15.7%). In preschool children (2–5 years), tree nuts remained the most frequent sensitization (51.7% vs. 13.7%), followed by egg (24.4% vs. 5.0%), milk (20.9% vs. 5.0%), and pollen (34.3% vs. 32.0%). For school-age children (6–12 years), pollen emerged as the leading sensitization in both cohorts (62.0% vs. 57.8%), followed by tree nuts (35.5% vs. 7.3%), fruit (19.9% vs. 22.3%), and panallergens (28.0% vs. 29.3%). In adolescents (13–18 years), pollen remained the primary allergen (64.9% vs. 67.1%), followed by panallergens (22.1% vs. 29.8%), tree nuts (9.4% vs. 6.7%), and fruit (9.1% vs. 18.7%).

Sensitization patterns in Ankara and Tehran reveal striking cultural and regional similarities, with food allergens (tree nuts, egg, and milk) dominating early childhood in both cohorts. While absolute prevalence rates differ—reflecting the targeted clinical utility of the ALEX test for poly-sensitized patients in Ankara compared to its broader application in Tehran—the sensitization series remains consistent across both capitals. As children age, a shared shift toward respiratory sensitizations (pollen and panallergens) is observed, suggesting that while shared dietary and cultural habits shape early-life profiles, geographical and climatic factors increasingly influence the molecular landscape through adolescence.