Of Attraction and Rejection — Asthma and the Microbial World

n the first half of the past century, it was thought that asthma was precipitated or prolonged by infection and that infection with several bacteria, including Streptococcus pneumoniae and Haemophilus influenzae, had a role in asthma.¹ Some investigators had suggested that bacterial allergy or chronic focal infection could be a cause of asthma.² More recently, population-based studies relating infections with Chlamydia pneumoniae and Mycoplasma pneumoniae to asthma severity encouraged a resurgent debate, but clinical trials involving various antibiotics failed to demonstrate sustained clinical benefit.¹

In this issue of the Journal, Bisgaard and colleagues⁷ propose an alternative explanation; that is, that bacterial colonization of the airways may induce neutrophilic inflammation in the airways and thereby cause asthma. In their prospective study, in which they followed children at risk of asthma from birth to age 5 years, detection of S. pneumoniae, H. influenzae, Moraxella catarrhalis, or a combination of these organisms in aspirates of the hypopharyngeal region at 4 weeks of age was a significant predictor of asthma, reversible airway obstruction, blood eosinophil concentration, and total IgE at age 5 years.

story