Viral respiratory infections provoke wheezing in many patients with asthma. It is our hypothesis that viral respiratory infections enhance the airway inflammatory response to antigen, thus provoking increased wheezing. To evaluate this possibility, 8 patients with allergic rhinitis were experimentally inoculated with rhinovirus (RV) 16. The airway response to antigen was evaluated by segmental bronchoprovocation with antigen. During the RV infection, and at recovery 4 weeks later, there was enhanced histamine release and recruitment of cells, particularly eosinophils, to the airway with antigen challenge. These findings suggest that RV infection can enhance the airway inflammatory response to antigen.