Clinical and inflammatory markers in asthma and COPD phenotyping

Abstract

Based on the studies described in this thesis, we conclude that adult-onset respiratory diseases (asthma and COPD) are heterogeneous conditions characterized by different clinical features and inflammatory characteristics. The first part of the thesis focused on phenotypes of adult-onset asthma. We showed that in patients with longstanding disease, three different clinical well-recognizable phenotypes can be identified, of which two are characterized by severe asthma. One of these severe asthma phenotypes can already be detected in the early stages of the disease. Furthermore, in newly diagnosed adult-onset asthma, CRS and nasal polyposis are associated with more severe airway inflammation. Therefore, this co-morbidity could be an early sign of severe asthma developing. Finally, measuring blood eosinophils is an accurate diagnostic tool for detecting this inflammatory phenotype in patients with asthma and is easy to measure in clinical practise. The second part of the thesis focused on new diagnostic tests to identify inflammatory phenotypes in patients with COPD. These patients might benefit from specific treatments but cannot be distinguished based on clinical characteristics. The mannitol challenge test and exhaled breath analysis are closely associated with the degree of airway inflammation. The tests are easy to perform and could be used in clinical practice to monitor airway inflammation