Defective cells in asthmatic lungs prolong viral infections
Asthmatics suffer longer bouts of respiratory infections because of an inappropriate response in deleting infected cells. Respiratory viral infections are associated with the majority of acute exacerbation of asthma, and of those approximately 60% are from human rhinoviruses (RVs). Adults with asthma have been shown to have an increase in severity and duration of naturally occurring viral infections, especially RV-16. The reasons for this are now becoming clear. There appears to be a defective innate immune response (IFN-b) in the asthmatic lung that causes chaos. Instead of infected cells ‘self-destructing’ and being ‘swept’ away as a normal defence mechanism, the asthmatic lung reacts slowly letting the infected cell die from the activity of the virus. This action sets off pro-inflammatory immune responses, which exacerbate asthma, and also release progeny viruses, which then infects neighbouring cells. For people with allergic asthma it is important that chronically inflamed airways (asthma) are kept to a minimum. Allergen recognition and avoidance plus properly prescribed medication are vital in health protection.
‘Innate Immunity in the Pathogenesis of Virus-induced Asthma Exacerbations’, Sebastian L. Johnston, The Proceedings of the American Thoracic Society, 2007, 4:267-270
