IL4 and cystic fibrosis: As discussed above, classical sputum and bronchoalveolar lavage fluid (BALF) prognostic biomarkers of CF include elevated levels of IL-8 chemokine and other cytokines, such as IL-10, IL-4, and TNF-alpha, as well as increased neutrophil elastase (NE) or myeloperoxidase (MPO) activity [2,4,10,11,13,43,62,63].