A32-03 Utility of Bronchoscopy in the Comprehensive Evaluation of Severe Asthma: Phenotype, Histology, Microbiology and Endoscopic Findings

Rationale Severe asthma remains a diagnostic and therapeutic challenge due to its marked clinical and inflammatory heterogeneity. Histological characterization of the airway by bronchial biopsy (BB) may improve the understanding of inflammatory phenotypes and assist in optimizing treatment selection. The aim of this study was to evaluate the clinical utility of fiberoptic bronchoscopy (FBC) with bronchial biopsy, using the García-Cossío histological score, in the phenotypic characterization of patients with uncontrolled severe asthma. Methods Patients with uncontrolled severe asthma who underwent FBC with BB between January and September 2025 were included. Statistical analysis was performed using Jamovi software. Quantitative data are presented as median and interquartile range (IQR), and qualitative data as absolute and relative frequencies. Results Eleven patients with severe asthma were included, with a median age of 53 years (IQR 12), predominantly female (63.6%), and mostly non-smokers (54.5%). Median age at diagnosis was 40 (28) years, and median disease duration 15 (27.5) years. The most frequent comorbidities were atopy (54.5%), depressive syndrome (27.3%), and obesity (36.4%). Median number of emergency visits in the previous year was 2 (1.5), FEV1 78 (33), and ACT score 10 (4.7). Before FBC, 45.5% of patients were classified as allergic T2, 18.2% as eosinophilic T2, 9.1% as mixed T2, and 9.1% as non-T2. One of the main histological findings was submucosal eosinophilic infiltration, observed in a substantial proportion of cases. After FBC, the phenotypic classification changed in several patients: two shifted from non-T2 to eosinophilic T2, and two from allergic T2 to mixed T2. These histological findings led to modifications in biologic therapy, as illustrated in Figure 1. Bronchoaspirate (BAS) cultures were positive in four patients (36.4%), identifying various potentially pathogenic microorganisms. Endoscopic abnormalities were found in four cases (36.4%), mainly tracheobronchomalacia, dynamic collapse, and bronchial stenosis. No complications were recorded during or after the procedure. In all cases (100%), bronchoscopy provided clinically relevant information that contributed to diagnostic and therapeutic decision-making. Conclusion FBC with BB provided valuable histological insights in patients with severe asthma, demonstrating submucosal eosinophilic infiltration in the majority of cases. Integrating histological, clinical, and functional data allowed phenotypic reclassification in 36.3% of patients, highlighting the relevance of tissue evaluation in poorly controlled asthma and in cases with discordance between peripheral biomarkers and clinical expression. Histological assessment may contribute to a more accurate and individualized selection of biologic therapy.