Sputum induction method for studying total IgE levels in atopic asthmatic patients

Abstract

Background : IgE antibodies have been considered to play an important role in the pathogenesis of atopic asthma. However, there have been only few studies on the role of IgE in airway secretion in the pathogenesis of bronchial asthma. This might be partly due to difficulty in sampling of airway secretion from asthmatic patients. Recently, sputum induction method by inhalation of nebulized hypertonic saline was developed, and proved to be valid and useful method for obtaining airway secretion from asthmatic patients for studying airway inflammation. Objective and method : To evaluate the usefulness of sputum induction method for studying IgE antibodies in airway secretion from atopic asthmatic patients, total IgE levels in induced sputum from 54 atopic asthmatics were measured by enzyme-linked immunosorbent assay(ELISA) and tried to find an association with sputum eosinophilia. Result : Total IgE levels in induced sputum were significantly higher in atopic asthmatic patients(1,27 ±82.066 IU/㎖) than in controls(0.203±0.291 IU/㎖)(p<0.05). In atopic asthmatic patients, total IgE levels in induced sputum were not significantly different between patients with and without sputum eosinophilia(≥5% of 200 counted leukocytes). There was a significant correlation of total IgE levels between induced sputum and serum in atopic asthmatic patients(r=0.60, p<0.05). Total IgE levels in induced sputum(1.278±2.066) were significantly higher than sativa sample(0..504±1.111 lu/㎖) from atopic asthmatic patients (p<0.05). Conclusion : These results suggest that total IgE levels are increased in the induced sputum of atopic asthmatic patients and sputum induction method is a useful tool for studying IgE antibodies in airway secretion from asthmatic patients.