This result supports the notion that the effects of corticosteroid treatment are not simply mediated through the prevention of IL-5 release from cells within the lung, and is in agreement with a previous observation, obtained in a different mouse model of allergic asthma, showing the effect of corticosteroids on eosinophils preceding that on the concentrations of IL-5 [24]. The gene discussed is IL5; the disease is allergic asthma.