The role of TNF-α in eosinophilic inflammation associated with RSV bronchiolitis

The purpose of our study was to investigate whether tumor necrosis factor (TNF)-alpha correlates with eosinophilic inflammation that occurs during a lower respiratory tract infection with the respiratory syncytial virus (RSV) in children. Sixty children with RSV bronchiolitis (RSV group) and 20 healthy children with no respiratory symptoms (Control group) were enrolled. We measured the nasal lavage fluid (NLF) Th2 cytokine (IL-5), proinflammatory cytokine (TNF-alpha, IL-8), eosinophil-active cytokine [granulocyte-macrophage colony stimulating factor (GM-CSF), IFN-gamma], and eosinophil-active chemokine (eotaxin, regulated on activation normal T cell excreted and secreted) levels for both groups. We also measured serum eosinophil-degranulation product (eosinophil-derived neurotoxin; EDN, eosinophil cationic protein; ECP) levels from RSV group. TNF-alpha, IL-8, GM-CSF, IFN-gamma, and eotaxin levels were significantly higher in the RSV group compared with the Control group. TNF-alpha correlated with GM-CSF (r = 0.87, p < 0.0001), IFN-gamma (r = 0.92, p < 0.0001), eotaxin (r = 0.64, p < 0.0001), and IL-8 (r = 0.84, p < 0.0001). TNF-alpha may have an important role in eosinophilic inflammation of airways in children with RSV bronchiolitis.