The effect of allergen-induced bronchoconstriction on concentration of 5-oxo-ETE in exhaled breath condensate of house dust mite-allergic patients.

BACKGROUND: Arachidonic acid metabolites regulate several aspects of airway function including inflammation, muscle contraction and mucous secretion.

OBJECTIVE: The aim of this study was to evaluate concentration of selected 5-lipoxygenase- and cyclooxygenase-derived eicosanoids in exhaled breath condensate (EBC) during allergen-induced bronchoconstriction.

METHODS: The study was performed on 24 allergic rhinitis/asthma patients sensitized to a house dust mite (HDM) Dermatophagoides pteronyssinus (Dp) and 13 healthy controls (HCs). Bronchial challenge with Dp extract was performed only in the allergic patients. EBC samples were collected before (T0 ) and during Dp-induced bronchoconstriction (TEAR ). Eicosanoid concentration was measured using HPLC-tandem mass spectrometry.

RESULTS: Significant bronchoconstriction after Dp challenge was demonstrated in 15 patients (Rs), while in 9 patients (NRs) no asthmatic response could be detected. At T0 the most abundant eicosanoids in EBC of HDM-allergic patients were LTB4 and 5-oxo-ETE, while in HCs EBC concentration of LTB4 was significantly greater than that of 5-oxo-ETE. Allergen challenge resulted in significant increase in EBC concentration of 5-oxo-ETE, LTD4 and 8-iso-PGE2 only in Rs. At TEAR , the relative change of 5-oxo-ETE concentration in EBC correlated with decrease of peripheral blood eosinophilia (R = -0.774; P = .0012). Moreover, the relative increase of 5-oxo-ETE in EBC at TEAR significantly correlated with the severity of the subsequent late asthmatic response (R = 0.683, P = .007).

CONCLUSION: Our study demonstrates significant up-regulation of 5-oxo-ETE synthesis in HDM-allergic patients and indicates possible involvement of that mediator in the pathogenesis of allergic asthma.