Airway and systemic eosinophilia in asthma: does site matter?

Asthma is a complex chronic inflammatory disorder of the airways. It involves several cell types and cellular elements, is associated with airway hyperresponsiveness, and is characterised by recurrent episodes of wheezing, breathlessness and cough. These symptoms restrict the patients’ daily activities, impact on their quality of life and, if severe and untreated, may lead to hospitalisation and death [1].