Biomarkers and Respiratory Omics as New CHildren Opportunities - Study of Clinical Outcomes and Predictivity Evaluation

The goal of this observational study is to improve the identification of biomarkers that predict disease progression and to assess the effectiveness of current therapies in children with asthma and protracted bacterial bronchitis. The main aim of the study is to evaluate the microbiome composition and diversity, cellular composition, and metabolomic profile. In addition, to assess their correlation on subsequent treatment and disease course in children with asthma, protracted bacterial bronchitis, and in those receiving inhaled glucocorticosteroids without a diagnosis of asthma. Participants will undergo fiberoptic bronchoscopy. During bronchoscopy, the performing physician will collect Bronchoalveolar lavage fluid samples for metagenomic and metabolomic analysis, as well as mucosal biopsies for histopathological evaluation.

Inclusion Criteria: * Age at the beginning of the study 0-17 years old * Clinical indication and qualification by the attending physician for fiberoptic bronchoscopy under general anesthesia: * Obstruction of the airways: * Suspicion of foreign body aspiration * Persistent stridor * Abnormal result of functional tests of respiratory system - flattening of inspiratory or expiratory curve, presence of restriction (tested vital capacity \48 hours have passed between suspicion of foreign body aspiration and interventional bronchoscopy * Children with foreign body aspiration having a foreign body located in the trachea