Monday, 6 December 2010
Non-eosinophilic asthma: importance and possible
Aim: To study the aetiology of asthma including the underlying inflammatory profiles.
Introduction: Asthma is a common chronic inflammatory disease of the airways characterized
by variable and recurring symptoms, airflow obstruction, and bronchospasm. Symptoms include
wheezing, cough, chest tightness, and shortness of breath.
There is increasing evidence that inflammatory mechanisms other than eosinophilic
inflammation may be involved in producing the final common pathway of enhanced bronchial
reactivity and reversible airflow obstruction that characterises asthma. A review of the literature
has shown that, at most, only 50% of asthma cases are attributable to eosinophilic airway
inflammation. It is hypothesised that a major proportion of asthma is based on neutrophilic
airway inflammation, possibly triggered by environmental exposure to bacterial endotoxin,
particulate air pollution, and ozone, as well as viral infections. If there are indeed two (or more)
subtypes of asthma, and if non-eosinophilic (neutrophil mediated) asthma is relatively common,
this would have major consequences for the treatment and prevention of asthma since most
treatment and prevention strategies are now almost entirely focused on allergic/eosinophilic
asthma and allergen avoidance measures, respectively. It is therefore important to study the
aetiology of asthma further, including the underlying inflammatory profiles.
Conclusion: Asthma is thus an inflammatory disease caused by the inflammation of bronchioles.
Also asthma cases are attributable to eosinophilic airway inflammation.
Keywords: Asthma, eosinophilic inflammation, bronchioles.