Eosinophil cationic protein and chemokines in nasopharyngeal secretions of infants with respiratory syncytial virus (RSV) bronchiolitis and non-RSV bronchiolitis

Bronchiolitis is a risk factor for the development of childhood asthma. Eosinophilic inflammation in airways plays an important role in the pathophysiology of both bronchiolitis and asthma. To investigate this inflammation, we measured the eosinophil cationic protein (ECP), regulated on activation normal T-cell expressed and secreted (RANTES) and eotaxin levels in nasopharyngeal secretions (NPS). Twenty-eight patients with RSV bronchiolitis (RSV group), 11 patients with non-RSV bronchiolitis (non-RSV group) and 7 controls were enrolled in this study. ECP, RANTES, and eotaxin levels were measured by enzyme immunoassays. The ECP level in the NPS of the RSV group was significantly higher than that in the NPS of the non-RSV group and controls. RANTES and eotaxin levels in infants with bronchiolitis were significantly higher than those in the controls, but there was no significant difference between the RSV and non-RSV groups. In conclusion, with regard to eosinophilic airway inflammation, as compared with non-RSV bronchiolitis, RSV bronchiolitis may be more similar to childhood asthma.