Lower number of plasmacytoid dendritic cells in peripheral blood of children with bronchiolitis following respiratory syncytial virus infection.

OBJECTIVES: Dendritic cells (DCs) are key mediators of allergic airway inflammation. Thus, it is important to understand the relationship between respiratory syncytial virus (RSV) infection and DCs, especially in children with RSV bronchiolitis. METHODS: We collected peripheral blood from 71 children with RSV bronchiolitis at the time of admission and 28 children who were followed up 3 months following admission. Flow cytometry was performed to detect dendritic cell immunophenotypes. RESULTS: Patients with RSV bronchiolitis exhibited significantly higher number of myeloid DCs and lower number of plasmacytoid DCs at the time of admission and 3 months following discharge, compared with healthy controls. These children had a significantly higher myeloid/plasmacytoid ratio 3 months after discharge compared with healthy controls. CONCLUSIONS: Among children with RSV bronchiolitis, there is an imbalance in peripheral blood myeloid/plasmacytoid ratio. The low number of plasmacytoid DCs in peripheral blood indicates the development of bronchiolitis due to RSV infection.

[Correlation between the numbers of peripheral blood dendritic cells and the clinical manifestations in children with respiratory syncytial virus bronchiolitis].

OBJECTIVE: To detect the quantity of peripheral blood myeloid dendritic cells (mDCs) and plasmacytoid dendritic cells (pDCs) in children with bronchiolitis infected by respiratory syncytial virus (RSV) and analyze the correlation with the severity of the disease. METHODS: PCR was used to detect RSV in nasopharyngeal secretions. Flow cytometry was performed on the peripheral blood to detect the quantity of mDCs and pDCs in 71 children with bronchiolitis by RSV infection (including mild, moderate and severe infection) and 48 healthy control infants. RESULTS: The quantity of peripheral blood mDCs in the children with bronchiolitis by RSV infection was significantly higher than that of healthy controls (P<0.01), while the number of pDCs was significantly lower than that of healthy controls (P<0.01). The children with severe bronchiolitis by RSV infection had significantly lower quantity of peripheral blood mDCs and pDCs as compared with the mild group (P<0.05). CONCLUSION: The number of mDCs in peripheral blood of the children with RSV bronchiolitis significantly increased at the early stage, and in contrast pDCs were reduced. The increased number of mDCs indicates that the clinical manifestations are slighter, and the decreased number of pDCs suggests more wheezing of the children.