Role of Epithelial Barrier Integrity in Biologic Treatment Response of Severe Asthmatics With/Out Chronic Rhinosinusitis With Nasal Polyps (CRSwNP).

Advances in understanding the pathophysiology of asthma development and severity have pointed towards a prominent role of the bronchial epithelium, especially in more chronic and severe disease. Studies suggest that airway eosinophilic inflammation in asthma is linked to epithelial injury and structural changes of the airways, co called airway wall remodeling. Together the chronic airway inflammation and remodeling are associated with bronchial hyperresponsiveness, fixed airflow obstruction or progressive loss of lung function and clinical severity of asthma. Chronic rhinosinusitis with nasal polyps (CRSwNP), is another respiratory inflammatory disease often co-existing with severe asthma, sharing similar pathophysiology. The investigators hypothesize that epithelial barrier integrity may play a role in the pathophysiology of severe eosinophilic asthma and nasal polyposis and in response to anti-IL5 therapy of severe asthmatics, and that shedding of epithelial barrier proteins may be used as biomarker in the management of severe asthma. In order to study that, the investigators will conduct a prospective cohort study of adult severe asthmatics with/out CRSwNP, who live on the island of Crete, Greece and who meet the criteria for entering anti-IL5 treatment, as assessed by pulmonologist. The participants will be recruited with a convenience sampling in a period of 2 years, under real life conditions, and will be followed up for 1 year after treatment initiation. A control group of subjects diagnosed with nasal polyposis without severe asthma will be used. Eligible subjects will undergo clinical assessment with radiological (CT) and endoscopic investigations. Samples of serum, sputum, nasal secretions, as well as nasal and bronchial biopsies will be obtain for assessing clinicopathological differences among the 3 groups but also response to anti-IL5 therapy in SEA w/o CRSwNP.