Associations between eosinophil mediators and asthma characteristics in adults: the EGEA study

Abstract

Eosinophil derived neurotoxin (EDN) and Eosinophil cationic protein (ECP) are two granule proteins released by activated eosinophils. Although their potential benefit as markers of asthma severity has been well-established in childhood asthma, studies in adults are scarce. We aimed to study the associations between ECP/EDN and various asthma characteristics in adults from the Epidemiological study on the Genetics and Environment of Asthma (EGEA). Cross-sectional analyses were performed in 941 adults at EGEA2 (second survey, 2003-2007). Asthma characteristics were defined by standardized questionnaire and lung function tests. Plasma ECP and EDN levels were measured by enzyme-linked immunosorbent assay. Longitudinal analyses investigated the associations between EDN level at EGEA2 and changes in asthma characteristics at EGEA3 (follow-up, 2011-2013). Generalized logistic models taking into account familial dependence and adjusted for age, sex, smoking and body mass index were used. At EGEA2, ECP and EDN were statistically associated with increased risk of current asthma, poorly controlled asthma, chronic bronchitis, asthma treatments use and bronchial hyperresponsiveness. (adjusted(a) OR ranging from 1.35 to 2.12). Associations with EDN were stronger and remained after further adjustment on ECP. Increased risk of asthma attacks was specifically associated with EDN. High EDN level at EGEA2 was associated with the onset and/or the persistence of current asthma and nocturnal symptoms at EGEA3 (aOR ranging from 1.61 to 2.47). Results suggest that both ECP and EDN are associated with asthma expression and that EDN could be a potential biomarker to monitor asthma evolution in adults.