Proteins in exhaled air in assessment of asthma in children

Particles in exhaled air (PExA) are lower in asthmatic children. We investigate protein distribution collected with PExA 2.0. Method: 50 randomly selected subjects (6-18 years) were included, a third were healthy controls (C). Asthma group (A) included subjects with doctor diagnosed asthma and subjects taking diagnostic lung function (LF) tests. Methods: PExA was assessed at baseline (a) and after bronchodilation test (b). Impacted particles were collected on two filters (a,b). Proteins were alkylated, digested and separated by liquid-chromatography, detected by mass spectrometry followed by search against Swiss-Prot human database to indentify proteins with at least two peptides and FDR >0.01. Results: Detection of different protein amounts in PExA was successfully assessed in children. Protein amounts in Group C and Group A did not significantly differ at baseline: 5.26 (CI95% 2.14-8.39) and 5.70 (CI95% 4.17-7.22) x10^10, respectively. After bronchodilation Group C demonstrated more different kinds of proteins than Group A, 274 vs. 229, p=0.038. (Fig1.) Protein amounts did not correlate with particles counts, age, hight, BMI, medication, symptoms, LF or exposure to tobacco smoke. Conclusions: Healthy and asthmatic children presented no difference in protein amounts in exhaled air. However, after bronchodilation healthy controls presented a larger variety in number of detected proteins.