Volatile Organic Compounds Breathprinting of U-BIOPRED Severe Asthma smokers/ex-smokers cohort

Introduction: Severe asthma is a heterogeneous disease and tobacco smoke is an important risk factor. Asthmatics who smoke show adverse effects on clinical, prognostic and therapeutic outcomes. Metabolomic analysis of volatile organic compounds (VOCs)in exhaled breath can be useful to identify a“severe asthma smoking phenotype” Aims: To investigate VOCs associated with a significant smoking history (>5 pack-years)in severe asthma by examining the breathomics data among severe asthma non-smokers(SAn)and severe asthma smokers/ex-smokers(SAs/ex)U-BIOPRED cohorts Methods: Breathomics and clinical data were obtained from 34 SAn and 14 SAs/ex(13 ex-smokers and one current smoker, as assessed by urinary cotinine).Exhaled breath was collected in Tedlar bags and VOCs trapped on Tenax tubes. VOCs were desorbed and analysed by GC-MS at Philips Research. ANOVA adjusted for age and sex was applied and p Results: VOCs comparison between SAn and SAs/ex showed a significant difference in 29 VOCs:23 were increased in SAs/ex, while six VOCs were decreased in SAs/ex.Identified VOCs include hydrocarbons, ketones, nitriles, and furans.Acetonitrile, 2-hexenal and 1,4-cyclohexadiene were increased in SAs/ex with p Conclusions: Acetonitrile, 1,4-cyclohexadiene and furans were elevated in SAs/ex group, as several authors have reported in active smokers.However, patients in SAs/ex group were almost all ex-smokers. This implies that the observed differences are not due to active smoke per se, but potentially reflect differences in the airways nflammation/metabolism/microbiome associated with smoking history