Sensitization to Airborne Fungal Allergens Associates with Asthma and Allergic Rhinitis Presentation and Severity in the Singaporean/Malaysian Population

Fungal spores and conidia are the major components of total airspora in the tropical Asia environment, and their sensitization patterns are often associated with allergic diseases such as asthma, allergic rhinitis (AR), and atopic dermatitis. Hence, we recruited a cross-sectional cohort of 9223 Singapore/Malaysia Chinese adults and assessed their sensitization against Curvularia lunata allergen using the skin prick test approach. A subset of this cohort (n = 254) was also screened for specific Immunoglobulin E (sIgE) titers against a panel of 11 fungal allergens. We found significant association of Curvularia lunata sensitization with the risk of asthma (OR = 1.66, 95% CI: 1.17–2.33; p = 0.00391) and AR (OR = 1.69, 95% CI: 1.18–2.41; p = 0.00396). Among asthmatic patients (n = 1680), Curvularia lunata sensitization also increased frequencies of wheezing symptoms (OR = 1.81, 95% CI: 1.05–2.96; p = 0.0239), general practitioner/specialist visits (OR = 2.37, 95% CI: 1.13–4.61; p = 0.0157), and other asthma-related exacerbation events (OR = 2.14, 95% CI: 1.04–4.10; p = 0.0289). In our serum cohort, sensitization to Aspergillus spp. was the most common fungal sensitization, with 23.6% (n = 60) had a class 3 and above sensitization (positive sensitization; sIgE titers of > 3.5 kU/L) against this allergen. Increasing sIgE titer against Aspergillus spp. was also correlated with increased AR risk and AR-related symptoms. In conclusion, our findings emphasize an important role of fungal sensitization in the manifestations of asthma and AR in the Southeast Asian Chinese population.

Initiation and Pathogenesis of Severe Asthma with Fungal Sensitization

Fungi represent one of the most diverse and abundant eukaryotes on earth, and their ubiquity and small proteolytically active products make them pervasive allergens that affect humans and other mammals. The immunologic parameters surrounding fungal allergies are still not fully elucidated despite their importance given that a large proportion of severe asthmatics are sensitized to fungal allergens. Herein, we explore fungal allergic asthma with emphasis on mouse models that recapitulate the characteristics of human disease, and the main leukocyte players in the pathogenesis of fungal allergies. The endogenous mycobiome may also contribute to fungal asthma, a phenomenon that we discuss only superficially, as much remains to be discovered.

Important issues of fungal sensitization: aerobiological aspects

Aim: to assess the dynamics of mold sporulation in Samara to predict the risk of allergy development and exacerbation. Patients and Methods: mold spore samples were collected from April 1 to September 30 in 2016–2019 using trap impactor and placed on slides coated with Vaseline-wax mixture. Mold spores were calculated and referred to various taxa. Allergy risks were predicted. Thresholds for evoking asthma are estimated to be 100 spores/m3 for Alternaria and 3,000 spores/m3 for Cladosporium. Results: in Samara, average mold vegetative period was 164 days. Cladosporium and Alternaria spores were identified. Their spores were estimated as 34.4% of total atmospheric spores in Samara. Cladosporium spores estimated as 15.3% of total fungal spores were identified during the whole observation period. Maximum concentration was less than 960 spores/m3 having been within the average range. Alternaria spores were estimated as 19.1%. The proportion of days exceeding the threshold value of 100 spores/m3 was 6% to 81% having been the highest in July-September. Conclusion: prerequisites for the development of fungal sensitization were revealed. Regional specificity of sporulation in Samara was illustrated. Major mold taxa were identified. Allergy risks in Alternaria and Cladosporium sensitization were assessed. The highest total average monthly amount of Alternaria spores was during Artemisia and Ambrosia pollination season. This could be challenging for the diagnosis and treatment of patients suffering from allergic symptom exacerbations during this period. Our findings will improve the diagnosis, treatment, and prevention of allergic disorders in Samara. KEYWORDS: aerobiological monitoring, allergy, mold spores, Cladosporium, Alternaria, fungal sensitization. FOR CITATION: Mazokha K.S., Manzhos M.V., Khabibulina L.R. et al. Important issues of fungal sensitization: aerobiological aspects. Russian Medical Inquiry. 2021;5(1):4–9. DOI: 10.32364/2587-6821-2021-5-1-4-9.