Impact of community respiratory viral infections in urban children with asthma

Lewis, Toby C.; Metitiri, Ediri E.; Mentz, Graciela B.; Ren, Xiaodan; Goldsmith, Adam M.; Eder, Breanna N.; Wicklund, Kyra E.; Walsh, Megan P.; Comstock, Adam T.; Ricci, Jeannette M.; Brennan, Sean R.; Washington, Ginger L.; Owens, Kendall B.; Mukherjee, Bhramar; Robins, Thomas G.; Batterman, Stuart A.; Hershenson, Marc B.

BACKGROUND: Upper respiratory tract viral infections cause asthma exacerbations in children. However, the impact of natural colds on asthmatic children in the community, particularly in the high-risk urban environment, is less well-defined. OBJECTIVE: We hypothesized that children with high-symptom upper respiratory viral infections have reduced airway function and greater respiratory tract inflammation than children with virus-positive low-symptom illnesses or virus-negative upper respiratory tract symptoms. METHODS: We studied 53 asthmatic children from Detroit, Michigan during scheduled surveillance periods and self-reported respiratory illnesses for one year. Symptom score, spirometry, fraction of exhaled nitric oxide (FeNO) and nasal aspirate biomarkers, viral nucleic acid and rhinovirus (RV) copy number were assessed. RESULTS: Of 658 aspirates collected, 22.9% of surveillance samples and 33.7% of respiratory illnesses were virus-positive. Compared to the virus-negative asymptomatic condition, children with severe colds (symptom score ≥5) showed reduced forced expiratory flow at 25–75% of the pulmonary volume (FEF25–75), higher nasal mRNA expression of C-X-C motif chemokine ligand (CXCL)-10 and melanoma differentiation-associated protein 5, and higher protein abundance of CXCL8, CXCL10 and C-C motif chemokine ligands (CCL)-2, CCL4, CCL20 and CCL24. Children with mild (symptom score 1–4) and asymptomatic infections showed normal airway function and fewer biomarker elevations. Virus-negative cold-like illnesses demonstrated increased FeNO, minimal biomarker elevation and normal airflow. RV copy number was associated with nasal chemokine levels but not symptom score. CONCLUSION: Urban asthmatic children with high-symptom respiratory viral infections have reduced FEF25–75 and more elevations of nasal biomarkers than children with mild or asymptomatic infections, or virus-negative illnesses.