We found that the concentration of neutrophil elastase, in apical surface media of the nAEC cultures, was more than three-fold greater following neutrophil migration across RSV-infected epithelium for 4 h (but not 1 h) at 72 h post-infection (figure 5a and b) with a mean±sem of 2.0±0.6 mU·mL−1, compared to 0.6±0.1 mU·mL−1 in the mock-infected cultures (p=0.039) (figure 5b). This evidence concerns the gene ELANE and infection.