Breathprint of severe allergic asthma with SPME-GC-MS Analysis of exhaled air volatile organic compounds(Ege University translational pulmonology research group [EgeTPAG])

Defining severe allergic asthma by moleculer fingerprints may help developing proper protective measurements and individualized treatments.VolatileOrganicCompounds(VOCs)are the most studied biomarkers in exhaled breath samples today and they seem promising for molecular endotyping of asthma.Objective of this study is defining molecular endotypes of severe allergic asthma patients viaVOCs fingerprint in exhaled air. Severe allergic asthma patients according to the GINA 2015 were included in this prospective case-control study,along healthy controls.Atopic status was determined by skin-prick testing/specific IgE measurements in patients9 blood.Breath samples were collected via lab-made sample collector where the VOC content was enriched on a polythiophene solid phase microextraction(SPME)fibers.Then,theVOC profile was analyzed by inserting into injection port of a gas chromatography coupled with mass detector(GC-MS)allowing thermal desorption.Commercial Carboxen/Polydimethylsiloxane SPME fiber was also utilized. Atotalof 27severe allergic asthma patients along with 42healthy controls9 breath samples were collectedand analyzed.The results were interpreted with chemometric approach by using Neurol Network classification algorithm inWEKA. According to the first preliminary results of the study;this technique is able to significant discriminate between patients with asthmaand controls with greater accuracy.There was significantly different signal level of VOCs mixture in NN classification algorithm.The using algorithm in WEKA gave a sensitivity of95.6%,a specificity of95.8%with a success rate of88.6%in the training set.