Application of PTR-TOF-MS to investigate metabolites in exhaled breath of patients affected by coeliac disease under gluten free diet

Coeliac disease (CD) is a common chronic inflammatory disorder of the small bowel induced in genetically susceptible people by the exposure to gliadin gluten. Even though several tests are available to assist the diagnosis, CD remains a biopsy-defined disorder, thus any non-invasive or less invasive diagnostic tool may be beneficial. The analysis of volatile metabolites in exhaled breath, given its non-invasive nature, is particularly promising as a screening tool of disease in symptomatic or non-symptomatic patients. In this preliminary study the proton transfer reaction time of flight mass spectrometry coupled to a buffered end-tidal on-line sampler to investigate metabolites in the exhaled breath of patients affected by coeliac disease under a gluten free diet was applied. Both H3O+ or NO+ were used as precursor ions. In our investigation no differences were found in the exhaled breath of CD patients compared to healthy controls. In this study, 33 subjects were enrolled: 16 patients with CD, all adhering a gluten free diet, and 17 healthy controls. CD patients did not show any symptom of the disease at the time of breath analysis; thus the absence of discrimination from healthy controls was not surprising