Impact of an increase in the inhaled corticosteroid dose on blood eosinophils in asthma.

Here, we report that increasing treatment with inhaled corticosteroids (ICS) in patients with not well-controlled asthma from a medium to a high dose results in a profound reduction of blood eosinophils (median fall in blood eosinophil concentrations from 560 to 320 cells/µL). Therefore, 'normal values' of blood eosinophils in patients with asthma need to be considered in view of the individual ICS doses of the patients. In addition, increases in the dose of ICS may result in blood eosinophil concentrations which would formally preclude treatment with biologics targeting the interleukin-5 pathway.