title: A new approach to study exhaled proteins as potential biomarkers for asthma.
abstract: BACKGROUND
  Asthma is a complex clinical disease characterized by airway inflammation. Recently, various studies reported on the analysis of exhaled breath condensate (EBC) in the search for potential biomarkers for asthma. However, in a complex disease such as asthma, one biomarker might not be enough for early diagnosis or follow-up.
  
  
  OBJECTIVE
  The use of proteome analysis may reveal disease-specific proteolytic peptide or protein patterns, and may lead to the identification of novel proteins for the detection of asthma.
  
  
  METHODS
  Liquid chromatography and mass spectrometry were used to separate and detect proteins (proteolytic peptides) present in EBC samples from 30 healthy children and 40 children with asthma in the age group of 6-12 years.
  
  
  RESULTS
  Support vector machine analysis resulted in differentiating profiles based on asthma status. These proteolytic peptide patterns were not correlated to some well known (spirometry, exhaled nitric oxide) and more recently described exhaled markers (EBC pH, LTB₄). The more abundant proteins in EBC were identified as cytokeratins, albumin, actin, haemoglobin, lysozyme, dermcidin, and calgranulin B.
  
  
  CONCLUSIONS
  Although the exact role in the disease development or physiological state of the airways of the proteins described in the presented pattern is not clear at this moment, this is an important step in the search for exhaled biomarkers for asthma. This study shows that EBC contains proteins that are of interest for future non-invasive asthma diagnosis or follow-up.
authors.affiliation: Flemish Institute for Technological Research (VITO), Environmental Risk and Health, Toxicology, Mol, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Bloemen
authors.forename: R
authors.initials: R
authors.lastname: Van Den Heuvel
authors.forename: E
authors.initials: E
authors.lastname: Govarts
authors.forename: J
authors.initials: J
authors.lastname: Hooyberghs
authors.forename: V
authors.initials: V
authors.lastname: Nelen
authors.forename: E
authors.initials: E
authors.lastname: Witters
authors.forename: K
authors.initials: K
authors.lastname: Desager
authors.forename: G
authors.initials: G
authors.lastname: Schoeters
mesh_terms: D001249:Asthma / Q000175:diagnosis*; D015415:Biomarkers / Q000032:analysis*; D001944:Breath Tests / Q000379:methods*; D002648:Child; D002853:Chromatography, Liquid; D045853:Exhalation; D005260:Female; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D040901:Proteomics / Q000379:methods*
chemical_list: D015415:Biomarkers