Background: Serum eosinophil cationic protein (ECP) has been promoted as a marker of inflammatory activity in bronchial asthma. Bronchial responsiveness, measured either by inhaling pharmacologically active substances such as histamine or methacholine, or by applying physical stimuli such as the hyperventilation of cold dry air, is also considered to be an indirect marker of bronchial inflammation.
Objectives: In this study, we investigated the possible relationship between serum ECP and bronchial responsiveness to both cold dry air and histamine in presently symptom- and medication-free pediatric and adolescent asthma patients.
Subjects: Thirty-six children and adolescents with atopic asthma were studied.
Methods: On 2 consecutive days, bronchial responsiveness was assessed nonpharmacologically by cold dry air and pharmacologically by histamine in random order. Blood samples for determination of ECP were collected before each challenge.
Results: Serum ECP levels correlated with neither cold dry air-induced changes in FEV1 nor the provocation concentrations of histamine causing a 20% fall in FEV1. Subjects with bronchial hyperresponsiveness to cold dry air and histamine had somewhat higher levels of serum ECP than subjects with normal responses, but these differences were insignificant.
Conclusions: Our results indicate a lack of relationship both between serum ECP and bronchial responsiveness to cold dry air and between serum ECP and bronchial responsiveness to histamine.