ELANE and viral infectious disease: In addition to the recruitment of eosinophils to the airway, viral infection can increase the number of neutrophils in the airway, which can produce neutrophil extracellular traps, neutrophil elastase (Elane), leukotrienes (LTs), matrix metalloproteinases (MMPs, especially MMP8 and MMP9), and reactive oxygen species, contributing to further eosinophil accumulation and mucus hypersecretion by goblet cells9,12,13.