The use of serum eosinophil cationic protein (ECP) in the management of steroid therapy in chronic asthma

Abstract

Corticosteroid therapy has become the mainstay in the treatment of asthma. However, the risk-benefit balance in the patient calls for assessment of the state of inflammation in the airways. In this respect serum eosinophil cationic protein (ECP) might be a marker, which can easily be measured in a clinical setting. Studies have indicated a relation between level of serum ECP and activity and severity in asthma. To investigate the feasibility to guide steroid therapy on the basis of the level of serum ECP in patients with chronic asthma. Twenty adult patients on maintenance inhaled steroid therapy visited the chest clinic once every 2 months over a 12-month period. At each visit a short history, blood sample for ECP and number of eosinophils, baseline spirometry, and histamine inhalation provocation test (PC20) were obtained. On the basis of level of ECP, adjustments in daily dose of steroids were considered. Data were compared with those of a previous 6-month ECP evaluation study in these same patients. In 10 patients mean dose of inhaled steroids was decreased > or = 25%. ECP rose slightly (antilogged mean from 9.06 to 11.8 micrograms/L) and lung function decreased slightly (mean FEV1 %predicted from 85.5 to 81.6). In seven patients mean dose of inhaled or oral (n = 2) steroids was increased > or = 25%. In this group ECP decreased but remained elevated at > or = 20 micrograms/L (antilogged mean from 30.5 to 25.6 micrograms/L) and lung function improved (mean FEV1 %predicted from 67.2 to 74.5). In both groups patients' scores of asthmatic well-being increased significantly, and PC20 did not show a trend. Exacerbation rate remained the same in the decreased and the no change group (n = 3, in which no substantial change in steroid dose occurred), but was reduced by about 50% in the increased group. From this observational study it is concluded that adjusting steroid therapy guided by serum ECP-level may be helpful in tailoring asthma treatment.