Similar Colds in Allergic Asthma Subjects and Non-Atopic Subjects After Inoculation with Rhinovirus-16

Background— Rhinovirus infections are frequent causes of asthma exacerbations. Objective— This study was conducted to test whether subjects with and without allergic asthma have different responses to infection, and to identify baseline patient risk factors that predict cold outcomes. Methods— Twenty mild persistent allergic asthma and 18 normal subjects were experimentally inoculated with type 16 rhinovirus. Subjects were evaluated at baseline, during the acute infection and during recovery for asthma and cold symptoms by validated questionnaire. Sputum and nasal lavage were evaluated for viral shedding, cytokines, and cellular inflammation. Results— There were no group-specific significant differences in peak cold symptom score (10.0 ± 5.8 vs 11.1 ± 6.2, asthma vs normal), peak nasal viral titers (log 10 4.3 ± 0.8 vs 3.7 ± 1.4 TCID 50 / mL), or change in peak flow during the study (10% ± 10% vs 8% ± 6%). RV16 infection increased peak asthma index values in the asthma group (median 6 → 13, p=0.003), but only marginally in the normal group (median 4 → 7, p=0.09). More asthma subjects had detectable eosinophils in nasal lavage and sputum samples associated with cold symptoms while CCL2 (MCP-1) levels were inversely associated with nasal viral shedding. Conclusions— These findings suggest that mild allergic asthma and normal subjects have similar cold symptoms, inflammatory and antiviral responses. In addition, eosinophilia and other selective baseline measures of airway inflammation in subjects with or without asthma may predict respiratory outcomes with rhinovirus infection.