E-cadherin as an epithelial barrier protein in exhaled breath condensate

Airway epithelium plays an important role as a physical barrier and a modulator of allergic response. Junctions between cells provide epithelial integrity and barrier function. The aim of this study was to investigate the influence of atopy on airway epithelial integrity in asthma and to measure E-cadherin levels in exhaled breath condensate as an indicator epithelial damage. A total of 74 patients with asthma (35 atopic and 39 non-atopic) and 39 healthy children were enrolled in this case-control study. Sociodemographic characteristics and asthma severity parameters in the last three-month period were recorded and pulmonary function tests were performed. Blood samples were obtained to measure serum immunoglobulin E (IgE) levels and peripheral blood eosinophil count, and exhaled breath condensate (EBC) was obtained to measure E-cadherin.EBC E-cadherin levels were significantly lower in the asthmatics when compared to non-atopic controls (0.109 (0.076) versus 0.191 (0.184) ng mL(-1) respectively, p = 0.01). Atopic and non-atopic asthmatic groups had lower EBC E-cadherin levels compared to the control group. (0.112 (0.060) ng ml(-1), 0.106 (0.089) ng ml(-1) and 0.191 (0.184) ng ml(-1), p = 0.02 and p < 0.01 respectively). However, EBC E-cadherin levels were not different between atopic and non-atopic asthmatics. The results of our study support the role of E-cadherin in the pathogenesis of asthma. However, the absence of difference in E-cadherin levels between atopic and non-atopic asthmatics suggests that allergic sensitization is not the primary factor for development of epithelial barrier dysfunction in asthma.