Serum eosinophil cationic protein in asthma of farmers

Objective: There is need for relevant markers of bronchial inflammation in epidemiologic studies of asthma. Serum eosinophil cationic protein (ECP) is a marker of eosinophil inflammation and asthma activity. We have studied s erum ECP in atopic farmers with current asthma, in non-atopic asthmatics an d in non-asthmatic, non-atopic controls. Methods and results: In a cross-se ctional study of a representative sample of 8482 farmers in Norway, asthma was recorded using a self-administered questionnaire; spirometry and serum sampling were performed on all of them. Atopy was screened with Phadiatop a nd RAST analyses to the mites Lepidoglyphus destructor and Tyrophagus putre scentiae in all asthma cases and controls. All the identified atopics had a dditional RAST analyses on a set of allergens. Serum ECP was tested in 60 p ersons with current asthma and atopy (mean 16.2, 95% CI 13.2-19.3), 127 non -atopic asthmatics (mean 9.1, 95% CI 8.0-10.2) and 39 non-atopic controls ( mean 5.5, 95% CI 4.0-7.0). ECP levels in atopic asthmatics were associated with number of positive allergens and reduction of FEV1 values. Moreover, t he ECP levels were elevated with allergy to swine, cow, D. pteronyssinus, L . destructor, A. sire, T. putrescentiae, timothy grass and the cereal grain s: wheat, oat, barley and rye. Conclusion: Serum ECP seems feasible as an i ndicator of inflammatory activity in epidemiological studies of current all ergic asthma, and may help to indicate the importance of specific allergens . Although the ECP values were significantly more elevated in atopic than i n non-atopic asthma, elevated serum ECP was not specific for atopic asthma.