Feasibility of a new method to collect exhaled breath condensate in pre-school children.

Exhaled breath condensate (EBC) is a promising non-invasive method to assess respiratory inflammation in adults and children with lung disease. Especially in pre-school children, condensate collection is hampered by long sampling times because of open-ended collection systems. We aimed to assess the feasibility of condensate collection in pre-school children using a closed glass condenser with breath recirculation system, which also collects the residual non-condensed exhaled breath, and subsequently recirculates it back into the condenser. Condensate was collected before and after breath recirculation in 70 non-sedated pre-school children with and without recurrent wheeze. Cytokines (IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-13, TNF-α) were measured in 50 μl samples using ultrasensitive multiplexed liquid bead array. The success rate of condensate collection increased from 64% (without recirculation) to 83% (after breath recirculation), and mean condensate volume from 214 to 465 μl respectively. Detection of cytokines was successful in 95-100% of samples. Cytokine concentrations before and after breath recirculation were not different (p > 0.232). In asthmatic children, only TNF-α concentrations were significantly decreased, compared to non-asthmatics. In pre-school children, the collection of EBC is feasible using a new closed glass condenser with breath recirculation system. This new method may help to assess - non-invasively - cytokine profiles in asthmatic and non-asthmatic pre-school children.