Plots showing difference in levels of sputum cytokines between severe asthma patients with FeNO ≤40 versus >40 after treatment with anti-IL-5 biologic. Dotted lines are the normal values based on the 90th percentile of 22 non-atopic healthy donors (mean age 49+/-15) with no evidence of airway eosinophilia. IL-4 and IL-13 are significantly higher in the raised FeNO group. The pink asterisk is an outlier and details on this patient are shown in the online repository. IL interleukin; FeNO Fraction of Nitric Oxid.