Detection and quantitation of total and allergen specific IgE in the bronchial mucosa of atopic and non-atopic asthmatics

摘要

RationaleIgE is thought to play a role in asthma pathogenesis. We hypothesised that aeroallergen-specific IgE is detectable in the bronchial mucosa of asthmatics regardless of their conventional atopic status.MethodsAtopic (n=9) and non-atopic (n=8) asthmatics as well as non-atopic nonasthmatic controls (n=8) were recruited with informed consent according to an ethically approved protocol. Biopsies were collected at fibreoptic bronchoscopy along with venous blood serum samples. Total and allergen component specific IgE were measured using Phadia ImmunoCAP and ImmunoCAP- ISAC microarray respectively in the sera and biopsy homogenates.ResultsIgE was detectable in the serum and bronchial mucosal homogenates in all groups. The median serum total IgE concentration was significantly elevated in the atopic, but not the non-atopic asthmatics as compared with the non-atopic nonasthmatics. In contrast, the median total IgE concentration in the biopsy homogenates was significantly higher in the non-atopic, but not the atopic asthmatics compared with the controls. Allergen component-specific IgE species were not detectable by ISAC in the sera or biopsy homogenates of the non-atopic asthmatics and controls. Allergen component-specific IgE species were detectable in the sera and biopsy homogenates of the atopic asthmatics. The relative concentrations of some of these components were higher in the mucosa than in the serum.ConclusionsIt is possible to extract and characterise IgE from bronchial mucosal biopsies. IgE is detectable in the bronchial mucosa of non-atopic asthmatics but is not directed against a wide range of common aeroallergen components. The specificities and functional activities of these IgE species remain to be investigated.