Due to a complex dysregulation of adaptive and innate immune cell function and interplay (11, 12), the lung tissue, bronchoalveolar lavage (BAL) and sputum of CF patients are characterized by increased levels of inflammation-promoting chemokines and cytokines, including for instance IL-8, GM-CSF, IL-6, CCL2, CCL3, CCL4, CCL20, TNF-α, IL-1β, IL-17, IL-23, G-CSF, IL-9, and IL-33 (10, 13–16). This evidence concerns the gene IL9 and cystic fibrosis.