Background: The measurement of several mediators in exhaled breath condensate (EBC) can be useful as the biomarker for asthma. But there are a few reports about EBC of asthmatics in Japan.
Aim: We examined the safety of the collection of EBC and the utility of cysteinyl leukotriene (cysLTs) in EBC as the biomarker of asthma.
Methods: Fifty-three asthmatics and eleven subjects without asthma were recruited. After the measuring of exhaled nitric oxide (eNO) and spirometory, EBC were collected. The levels of cysLTs in EBC were measurement by ELISA within 2 months.
Results: The collection of EBC did not induce any other symptoms in all subjects. In 48 subjects, the collection significantly increased their FEV1 and MMF level (DeltaFEV1: 2.27+/-0.77%, DeltaMMF 14.6+/-3.92% (mean+/-SEM). The level of cysLTs in EBC on asthmatics treated with high-dose ICS was significantly high compared with control group (p=0.0034), steroid-naïve asthmatics or asthmatics treated with low-dose ICS (steroid naive vs. high dose ICS, p=0.041, low dose ICS vs. high dose ICS, p=0.021). The relationship between cysLTs in EBC and the levels of LTE4 in urine was significantly correlated (n=34, r=0.32, p=0.0435). The relationship between cysLTs in EBC and the levels of eNO was significantly correlated only in steroid-naïve asthmatics (r=-0.57, p=0.0369). There was no relationship between cysLTs in EBC and FEV1, or log PC20Ach.
Conclusion: The collection of EBC was perfectly non-invasive. The level of cysLTs can be useful as a biomarker of asthma.