The Interactions of Virus Infection and Allergy
Respiratory viruses, particularly rhinoviruses (RV), are the most common cause of asthma exacerbations. Approximately 80% of asthma exacerbations in schoolaged children and about 50% of exacerbations in adults have been associated with viral infections, of which rhinovirus is the most common (1,2). Although these events are common, the mechanisms by which a respiratory infection exacerbates asthma are not fully understood. Many studies have been conducted in humans, animals, and respiratory cell cultures to evaluate the interactions of viral infection with the allergic response. This review addresses two observations that stem from these experiments. First, there are distinct features of the immune response to viral infection in atopic individuals, and evidence for an interaction between allergic and virus-induced inﬂammation. Second, individuals with atopic disease may have different lower airway and immune responses to viral infection than normal individuals, and these differences may contribute to the viral effects on airway function.