IFNG and cystic fibrosis: In the case of IL-17A, a trend towards a negative correlation between IL-17A levels in response to PHA and lung function was observed when the CF patients were considered as a single population (Fig. 2A), and this trend became significant only when CF/Chronic PA patients were considered and FEV1 was expressed as % predicted (Fig. 2B; S8 Fig.) (CF/Chronic PA patients, IFN-γ vs. % predicted FEV1: r = -0.552, p = 0.0341).