Novel Inflammatory Markers in Different Phenotypes of Severe Asthma

Asthma is a highly prevalent chronic airway inflammatory disease characterized by airway hyper-responsiveness, reversible airflow obstruction and increased mucus secretion, involving large and small airways. An emerging sub-phenotype of severe asthma is the late onset disease associated with nasal polyposis, a frequent co-morbidity that significantly impacts lung function and symptom control. On the basis of the infiltrate found in the sputum, asthma can be divided into four distinct phenotypes: eosinophilic, neutrophilic, mixed granulocytic and pauci-granulocytic. The majority of patients with eosinophilic asthma are sensitive to corticosteroids, and biological therapies targeting eosinophils (anti-Interleukin (IL)-5 and anti-IL5R) have been recently approved. However, it is known that some asthmatics, particularly those who have severe disease and are resistant to corticosteroids, have elevated neutrophil counts in the airway where they play a vital role in the exacerbation of the disease. However, the precise role of neutrophils in severe asthma and the mechanisms involved in neutrophil-induced tissue damage have not been clarified yet.

The hypothesis of the study is that neutrophils and eosinophils can contribute to the severity of asthma by changing their phenotypes according to the airway environment. Thus, a better understanding of the roles of neutrophils and eosinophils in severe asthma may lead to the identification of novel biomarkers and the development of new therapeutic approaches in different phenotypes of severe asthma.