Introduction: Exhaled breath condensate includes substances released from upper, lower airways and alveolar surfaces. Nitric oxide (NO) is the biologically active substance, playing huge role in physiology and patophysiology of living organisms. The quantitative determination of its concentration in exhaled air provides important information about processing disease processes in respiratory system. Interleukin 4 (IL-4) is the proinflammatory cytokine and its concentration in exhaled air condensate rises when there is exacerbation of asthma. The aim of this study was to answer the question whether determination of NO and IL-4 concentrations in exhaled breath condensate can be useful in evaluation of asthma exacerbation in children?

Material and methods: We evaluated 31 children divided into three groups. First group consisted of 7 children with asthma exacerbation in progress, second group consisted of 9 children with asthma, but actually asymptomatic and treated with inhaled drugs and third group included children with asthma but with no signs and with no need of treatment for over three months. Control group consisted of 15 healthy children. Exhaled breath condensate was collected for 15 minutes. Concentration of IL-4 and NO was determined with ELISA method.

Results: The highest levels of NO were obtained from children with asthma exacerbation and it was average 9,3 µmol/ml. This values were statistically significantly different from values obtained from the second group, where mean NO levels reached 3,38 µmol/ml. In children from the third group mean value of NO was 2,42 µmol/ml and in healthy children level of NO was the lowest and it reached 0,65 µmol/ml. Concentration of IL-4  in the exhaled breath condensate was the highest in the first group, it reached average 51 pg/ml. In the second group mean value of IL-4 was 41 pg/ml, the difference was statistically significant. Average values of IL-4 concentration in the third group were the lowest among all children with asthma and it reached 37,11 pg/ml. In the control group mean value of IL-4 concentration was  32,85 pg/ml.

Conclusions: Values of NO and IL-4 concentration in exhaled breath condensate are elevated in patients with asthma irrespective of the quality of the disease control level. NO and IL-4 concentration in exhaled breath condensate correlates with clinical state of children with asthma. Determination of NO and IL-4 concentration in exhaled breath condensate can be useful in evaluation of asthma control.