Methods: One hundred and seventeen children who were hospitalized with RSV bronchiolitis/pneumonia were enrolled. The patients were divided according to serum IgE levels on admission: high IgE (N=49, more than 2 SDs from the mean levels for age-matched controls) and low IgE group (N=68). We investigated if there was any difference in clinical and laboratory findings, and recurrence of wheezing between 2 groups. Difference in IgE levels between severe (severity score≥3) and non-severe group was also studied.
Results: More frequent and prolonged fever was observed in high IgE group than low IgE group (P<0.05). The patients showing severe symptoms or respiratory difficulties were more frequently seen in high IgE group (P<0.01). There was no difference in parental allergy and atopic sensitization. Nearly same findings were observed in re-analysis of data from the patients with the 1st RSV lower respiratory infection, but recurrence of wheezing was significantly higher in high IgE group than in low IgE group (P<0.05). The patients with high IgE were more frequently seen in severe group than in non-severe group (P=0.01).
Conclusions: Our study showed that the children who presented with high serum IgE levels during RSV infection had more severe symptoms comparing with those with low IgE levels. It suggests that increased Th2 immune response induced by RSV infection might be associated with the severity of disease.