We report on a case in which five consecutive exacerbations of asthma were monitored by following serum eosinophil cationic protein (ECP) levels. The serum ECP level correlated well with each exacerbation and tended to increase even before the exacerbations of asthma became apparent. This case shows that serum levels of ECP can be useful markers of disease activity and may also be predictive markers for acute exacerbation.
