Rhinovirus (RV)-induced pulmonary exacerbations are common in cystic fibrosis (CF) and have been associated with impaired virus clearance by the CF airway epithelium in vitro. Here, we assess in vivo the association of RV prevalence and load with antiviral defense mechanisms, airway inflammation, and lung function parameters in children with CF compared with a control group and children with other chronic respiratory diseases.
RV presence and load were measured by real-time reverse transcription-polymerase chain reaction in BAL samples and were related to antiviral and inflammatory mediators measured in BAL and to clinical parameters.
BAL samples were obtained from children with CF (n = 195), non-CF bronchiectasis (n = 40), or asthma (n = 29) and from a control group (n = 35) at a median (interquartile range [IQR]) age of 8.2 (4.0-11.7) years. RV was detected in 73 samples (24.4%). RV prevalence was similar among groups. RV load (median [IQR] × 103 copies/mL) was higher in children with CF (143.0 [13.1-1530.0]), especially during pulmonary exacerbations, compared with children with asthma (3.0 [1.3-25.8], P = .006) and the control group (0.5 [0.3-0.5], P < .001), but similar to patients with non-CF bronchiectasis (122.1 [2.7-4423.5], P = not significant). In children with CF, RV load was negatively associated with interferon (IFN)-β and IFN-λ, IL-1ra levels, and FEV1, and positively with levels of the cytokines CXCL8 and CXCL10.
RV load in CF BAL is high, especially during exacerbated lung disease. Impaired production of antiviral mediators may lead to the high RV burden in the lower airways of children with CF. Whether high RV load is a cause or a consequence of inflammation needs further investigation in longitudinal studies.