D3.50 - Molecular Characterization of Allergen Sensitization and Clinical Associations in a Romanian Cohort Using ALEX² Multiplex Assay

Uncovering regional variations in aeroallergen sensitization is essential for guiding allergy diagnosis and management. Sensitization profiles vary across Europe, with Southern European studies reporting frequent sensitization to cypress pollen, whereas in Eastern Europe, ragweed pollen predominates. Contemporary multiplex assay-based data from Romania remain scarce.

We aimed to characterize current allergen sensitization patterns in a Romanian cohort of patients with allergic disease, using the ALEX² multiplex assay. We retrospectively analyzed patients evaluated in our clinic between January 2024 and December 2025 for allergic diseases [asthma, allergic rhinitis (AR), atopic dermatitis (AD) and IgE-mediated food allergy, including oral allergy syndrome (OAS)], who underwent ALEX² multiplex testing as part of their diagnostic work-up. The final cohort comprised 124 patients.

The median age was 34.5 years (IQR: 25-48), and 66.1% of patients were female. AR was present in 79.8% of cases, asthma in 39.5%, AD in 25.0%, and IgE-mediated food allergy in 29.8%, including 6.5% with OAS. Most patients (75.8%) exhibited multiple molecular sensitizations (median: 8, IQR: 2-15), while 16.8% showed no in vitro allergen sensitization. The most frequent sensitizations (specific IgE ≥ 0.3 kUA/L)  were to ragweed pollen (Amb a, Amb a 1, 37.1% each), cat epithelium (Fel d 1, 29.0%), grass pollens (Phl p 1, Lol p 1, 28.2% each; Cyn d 1, 23.4%; Cyn d, 21.7%), cryptomeria (Cry j 1, 21.0%), and house dust mite components (Der f 2, Der p 2, 16.13% each; Der p 1, 15.32%). Among ragweed pollen-sensitized patients, 95.9% were diagnosed with AR, confirming a statistically significant association (Fisher’s exact test, p<0.001), while asthma and AD were present in 30.6% and 24.5% of cases, respectively.

In this Romanian adult cohort, multiplex molecular analyses revealed a high burden of aeroallergen sensitization, ragweed pollen emerging as the leading allergen, consistent with the high regional exposure, and showing strong association with AR. In line with previous Eastern European reports, these findings reinforce the relevance of ragweed pollen allergy as an ongoing public health issue. The predominance of ragweed sensitization and the high prevalence of polysensitization underscore the need for comprehensive molecular diagnostic panels to support personalized management and region-specific prevention strategies.