Nasal Corynebacterium depletion is associated with polysensitization to inhalant allergens in adults.

BACKGROUND: Polysensitization to inhalant allergens is an important determinant of disease progression and severity in allergic conditions. Although microbial dysbiosis has been implicated in various allergic conditions, the association between nasal microbiome composition and polysensitization remains unclear. This study aimed to investigate the association between the nasal microbiome and airborne allergen sensitization burden in adults. METHODS: In this cross-sectional observational study, 278 adults were categorized into four groups based on the number of sensitizations (range: 0-9): zero, mono (1), oligo (2-3), and poly (≥4). Allergen-specific IgE levels were measured in blood samples. Nasal swabs were analyzed using 16S rRNA gene sequencing to characterize microbial composition and predict functional pathways. RESULTS: Age was inversely correlated with the number of sensitizations, while both total IgE levels and allergic rhinitis prevalence increased across groups. Corynebacterium, a dominant commensal genus in the nasal microbiome, was significantly reduced in the polysensitized group and was inversely correlated with sensitization burden. Although overall microbial diversity remained stable, the abundance and co-occurrence patterns of key genera, including Corynebacterium, were altered in polysensitized individuals. Functional predictions revealed reduced activity in pathways related to carbohydrate metabolism (e.g., d-galactose degradation), cofactor biosynthesis (e.g., biotin and folate), and amino acid metabolism, all essential for epithelial integrity and repair. CONCLUSIONS: Polysensitized individuals exhibit Corynebacterium depletion along with altered microbial interactions and metabolic potential. Thus, nasal microbiome dysbiosis may impair epithelial barrier function and contribute to allergen sensitization, serving as a potential target for preventive strategies.