Aims and objectives

Asthma is characterized by airway inflammation and airflow obstruction that, especially in children, is detected in the small airways. Our aim was to determine the major proteins in exhaled air in healthy and asthmatic children and relate these findings to asthmatic inflammation.

Methods

Eighteen healthy and 31 asthmatic children, aged 12.5 and 10.5 years, participated. Lung function tests were done and Particles of Exhaled air (PExA) were collected before (sample A) and after (sample B) bronchodilation. A specific breathing technique was used for collecting the particles by PExA 1.0 (PExA, Sweden). The proteins were calcylated, separated by liquid chromatography and analyzed by mass spectrometry. The abundances of accepted proteins were divided by individual flow volumes to make values comparative.

Results

In sample A, the mean PEx mass was significantly higher in controls (29.3 ng and 30.4 ng) than in asthmatics (10.1 ng and 10.5 ng) in both A (p=0.0019) and B (p=0.0016) samples.

In all, 863 proteins in sample A and 1181 in sample B were detected by mass spectrometry. From the fifty most abundant proteins per subject, altogether 136 proteins were noted in sample A and 164 proteins in sample B totalling in 225 different proteins of which 77 were common. Ten most abundant proteins were albumin, surfactant protein A, dermcidin, lactotransferrin, complement C3, trypsin 1, calmodulin-like protein 5, Ig2, antitrypsin and complement C4. 

Conclusions

Detection of proteins from the small airways by mass spectrometry in children was successful even from samples with low PExA mass. Immunologically interesting proteins were detected. Clustering analysis of the proteins among healthy and asthmatics are needed.