Published Online: June 26, 2013
It is increasingly recognized that asthma is not one single disease, but has several subtypes. The most common type of asthma occurs in children and is associated with allergies, whereas asthma that starts in adulthood is less common but may show a severe progressive course in a subset of patients. To identify these patients with severe, adult-onset asthma at an early stage, and to better understand the underlying mechanisms, it is important to determine whether they have distinct clinical characteristics or a specific type of airway inflammation.
In an original research article in The Journal of Allergy & Clinical Immunology (JACI) Amelink et al fully characterized 176 patients with adult-onset asthma with respect to clinical, functional and inflammatory markers. Of these, 78 patients had severe disease according to internationally agreed criteria and 98 patients had mild-moderate persistent adult-onset asthma.
The researchers found that patients with severe adult-onset asthma had more nasal symptoms and nasal polyposis, increased exhaled nitric oxide levels, higher blood neutrophils and sputum eosinophilia despite treatment and irrespective of age, gender and asthma duration. Further analyses showed that persistent eosinophilic airway inflammation and higher blood neutrophils were independently associated with having severe disease.
The authors’ findings suggest that severe adult-onset asthma is a distinct asthma subtype that has different underlying mechanisms as compared to milder forms of adult-onset asthma but also as compared to severe asthma in general.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.