From the Authors

From the authors:

We thank I. Horváth for his kind comments on our review “Biomarkers of lipid peroxidation, airway inflammation and asthma” 1, and agree that we have been imprecise with the use of the term “breath condensate”. The paper would be improved by replacing this term with “exhaled breath” in relation to ethane, pentane and nitric oxide measurements.

While there is an intuitive explanation for the presence of volatile substances in exhaled breath, the mechanisms by which nonvolatile substances enter expired breath are poorly understood and need to be further investigated. 8-iso-prostaglandin F_2α and malondialdehyde have been measured in breath condensate as markers of lipid peroxidation 2; however, it is, as yet, unknown whether this medium can be used for reliable measurement of antioxidant defences. Analysis of total and oxidised glutathione concentrations in induced sputum indicates that sputum supernatant is suitable for this purpose 3. Hence, we stand by our conclusions in this area.

At the moment both sputum induction and breath condensate collection are promising techniques. The most useful sampling technique remains to be determined and this is an important area of future research. Comparison of both sampling methods in a head-to-head study is needed to resolve this issue.