Future studies should therefore test if the combination of the two ‘biomarkers’, namely a low β2-agonist reversibility together with a high peripheral blood eosinophilia, might be a better predictor of response to anti-IL-5 therapy than either parameter alone or other markers such as fractioned exhaled nitric oxide currently used to predict treatment responses in asthma. Here, IL5 is linked to Increased total eosinophil count.