CXCL8 and cystic fibrosis: Becker et al. [90] had previously shown that ALI cultures obtained from lower airways (trachea and bronchi) behaved similarly to nasal cells: unstimulated non-CF and CF cultures produced similar amounts of IL-8 although at higher levels than nasal cells (2.3 ± 0.5 and 1.6 ± 0.4 ng/mL, respectively), indicating that upper and lower airways are not fully superimposable as concerning cytokine production.