Exhaled breath condensate in ILD with ultrasensitive cytokine measurement: paving the way of a non-invasive investigational tool

<bold>Background:</bold> Interstitial lung diseases (ILD) represent a medical challenge regarding their complex physiopathology and challenging diagnostic approach. To date, the potential of inflammatory biomarkers in disease prediction remains unclear. The goal of this study was to evaluate the potential of cytokines quantification with ultrasensitive ELISA on exhaled breath condensates (EBC) to differentiate healthy subjects (HS) and ILD patients. <bold>Methods:</bold> EBC from ILD and non ILD patients were analysed with MSD® ultrasensitive ELISA technology (a QuickPlex SQ 120 MM analyser and S-PLEX Proinflammatory Panel 1 and V-PLEX Viral Panel 2 kits). Measured cytokines were IFN-γ, IL-1β, IL-4, IL-6, IL-8, IL-10, TNF-α. Samples were run in duplicates. <bold>Results:</bold> EBC were collected from 40 ILD patients and 18 HS. S-plex sensitivity was insufficient, but cytokines were detected above the LOD on the V-plex in all samples except for IL-1b (90%) and IL-10 (40%). IL-4, IL-10 and IFN-γ were under-expressed in ILD compared to HS with no inter-run variability or confounding factor (such as age, smoking, or disease duration) in our ILD population (p>0.05). Cytokine levels did not allow to separate IPF from non IPF ILDs. <bold>Conclusions:</bold> Our study confirms the potential of cytokine measurement in EBC through an ultrasensitive method in ILD, paving the way of a new potential explorative approach in chronic fibrosing lung diseases. <fig><object-id>erj;64/suppl_68/PA4420/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>