Exhaled breath condensate (EBC) has emerged as a novel noninvasive technique for assessment of airway inflammation, and it provides information on airway lining fluid composition. Traditionally, such assessment relies on invasive diagnostic tools such as bronchial biopsy and bronchoalveolar lavage (BAL) to obtain specimens from the airway but it is very uncomfortable procedure especially for young patients. The aim of this study is to evaluate the effect of allergic disease, disease monitoring and exposure to tobacco smoke on airway inflammation measured by markers in exhaled breath condensate (EBC) in children with asthma allergic to house dust mite. Also, we aim to assess correlations between cytokine concentrations in EBC and clinical characteristic of the patients with exercise-induced bronchoconstriction as another phenotype of asthma.

Markers that can be identified in the EBC of patients with asthma include pH, hydrogen peroxide, nitrogen oxides, eicosanoids, isoprostanes, adenosine, certain cytokines, chemokines, and growth factors. Concentrations of these biomarkers are influenced by inflammation, oxidative stress, and can be modulated by therapeutic interventions. There is evidence that some markers in EBC differ between patients with asthma and controls, and some of them can correlate with asthma severity score, lung function. The aim of this study is to evaluate the effect of allergic disease, disease monitoring and exposure to tobacco smoke on airway inflammation measured by markers in exhaled breath condensate (EBC) in children with asthma allergic to house dust mite. We will also evaluate the effect of antiasthmatic treatment applied out of dust season on the number of exacerbations in "asthma epidemic" in September. We will evaluate the effect of exposure to tobacco smoke on antiasthmatic treatment.

Also, we aim to assess correlations between cytokine concentrations in EBC and clinical characteristic of the patients with exercise-induced bronchoconstriction (EIB) as another phenotype of asthma. At the first study vist patients with EIB underwent fractional exhaled nitric oxide measurement (FeNO) and baseline spirometry, performed exercise treadmill challenge (ETC) and EBC samples were obtained at the end of ETC.

Inclusion Criteria:

• children with mild to moderate asthma allergic to house dust mite exposed/nonexposed to tobacco smoke
• healthy children

Exclusion Criteria:

• sensitization to allergens other than house dust mites
• other chronic diseases
• asthma exacerbation
• pregnancy
• oral corticosteroids for 4 weeks before the study
• montelukast sodium for 2 weeks before the study