Similarly, eosinophils are activated by the RSV and the high levels of leukotriene C4, eosinophil-derived neurotoxin (EDN), and eosinophil cationic protein (ECP) detected in the respiratory tract in RSV bronchiolitis support their role during the acute phase of RSV infection (47). The gene discussed is RNASE2; the disease is respiratory syncytial virus bronchiolitis.