Methods: Fifty-three infants £ 12 months of age admitted with their first acute bronchiolitis were enrolled. Twenty-three of them were diagnosed to have respiratory syncytial virus (RSV) infection. MBL and SP-D were measured in serum samples obtained on admission and compared with the control levels. Respiratory symptom was defined to be severe when the patients showed rapid breathing, chest wall indrawing, and hypoxemia (<92%). At 1-year follow up, all infants were evaluated if they had experienced recurrent bronchiolitis and MBL or SP-D levels were assessed in relation to the recurrence of bronchiolitis.
Results: SP-D increased significantly in the patients with bronchiolitis (P<0.05), but MBL showed no significant difference compared to the control levels. SP-D level was significantly higher in the infants who had experienced recurrent bronchiolitis than in the infants who had not (P<0.05). No significant difference was found between RSV and non-RSV infection. There was no relation between MBL or SP-D levels and symptom severity. The patients with peripheral eosinophilia (>4%) showed significant higher MBL levels than their counterparts (P<0.05).
Conclusions: Our study suggests that SP-D is importantly involved in the pathogenesis of acute bronchiolitis in young infants and high SP-D level might be associated with recurrent bronchiolitis.