Serum eosinophil cationic protein for predicting the prognosis of a step-down in inhaled corticosteroid therapy in adult chronic asthmatics.

We investigated whether the serum concentration of eosinophil cationic protein (s-ECP) can be used to determine when a step-down in inhaled corticosteroid therapy is indicated for patients with chronic asthma. A total of 24 adult patients, whose symptoms were well controlled with inhaled beclomethasone dipropionate (iBDP), were studied. The dosage of iBDP was reduced by half once a month until the dose reached one-quarter of the original level. s-ECP and blood eosinophil counts were determined once a month before and during the 6-month period after the step-down. In 12 patients, moderate and frequent exacerbation occurred, thus requiring a return to the initial or twice the initial dose of iBDP. Thus, the step-down here was defined as unsuccessful. In the remaining 12 patients, the symptoms were stable over the course of the 6 months, and the step-down was defined as successful. s-ECP correlated with eosinophil counts in peripheral blood (EOS) in both the successful and the unsuccessful groups. Although EOS before the step-down did not differ significantly between the two groups, s-ECP was significantly higher in the unsuccessful group (mean 35.7 microg/L) than in the successful group (mean 17.0 microg/L, p < 0.03). Thus, s-ECP appears to be a useful marker for determining when a step-down in iBDP therapy is indicated, and thus may contribute to successful long-term management of chronic asthma.