In summary, neutrophil activation has been shown as a key precursor to the development of severe respiratory symptoms in children with RSV bronchiolitis.41 Here we have shown that contact of neutrophils with AECs and/or trans-epithelial migration through RSV-infected AECs is essential for upregulation of neutrophil activation markers, including CD11b expression. The gene discussed is ITGAM; the disease is respiratory syncytial virus bronchiolitis.