title: Exhaled breath markers of alveolar macrophage activity in sarcoidosis.
abstract: OBJECTIVE
  Granuloma formation in sarcoidosis is dependent upon the interaction between alveolar macrophages (AMs) and a CD4+-driven TH1 response. This study aimed to measure TNF-α and calcium ion concentrations as markers of AM activity, in addition to total protein as a non-specific inflammatory marker in the exhaled breath condensate (EBC) of patients with sarcoidosis as well as control subjects.
  
  
  METHODS
  EBC was collected from 17 sarcoidosis patients and 23 healthy volunteers. Protein was measured by the bicinchoninic acid assay, TNF-α concentration was measured by ELISA and Ca(2+) concentration was measured by inductively coupled plasma-mass spectrometry. Conductivity of EBC was assessed using a conductivity probe.
  
  
  RESULTS
  Total protein concentration was significantly elevated in EBC from patients with sarcoidosis compared to control subjects (19.51 ± 4.52 vs. 10.60 ± 1.31 µg/ml, p = 0.020), as was TNF-α (3.37 ± 0.38 vs. 2.59 ± 0.40 pg/ml, p = 0.037) and conductivity (66.68 ± 16.73 vs. 36.85 ± 3.070 µS/cm, p = 0.044). EBC Ca(2+) concentration was significantly higher in healthy controls compared to patients with sarcoidosis (116.50 ± 12.19 vs. 73.88 ± 13.35 µmol/l, p = 0.018), although this was in the context of normal serum Ca(2+) in the sarcoidosis cohort.
  
  
  CONCLUSIONS
  Total protein and TNF-α concentrations were elevated in EBC from patients with sarcoidosis and could indicate disease activity. The reduction in EBC Ca(2+) concentrations could represent granulomatous activity in the lung.
authors.affiliation: Prince of Wales Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia. n.mohan@unswalumni.com.|Department of Respiratory Medicine, Prince of Wales Hospital, Sydney, NSW, Australia. n.mohan@unswalumni.com.
authors.forename: Nitin
authors.initials: N
authors.lastname: Mohan
authors.affiliation: Elemental Analysis Laboratory, SSEAU, Mark Wainwright Analytical Centre, University of New South Wales, Sydney, NSW, Australia.
authors.forename: Rabeya
authors.initials: R
authors.lastname: Akter
authors.affiliation: Inflammation and Infection Research, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.
authors.forename: Katherine
authors.initials: K
authors.lastname: Bryant
authors.affiliation: Inflammation and Infection Research, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.
authors.forename: Cristan
authors.initials: C
authors.lastname: Herbert
authors.affiliation: Inflammation and Infection Research, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.
authors.forename: Sharron
authors.initials: S
authors.lastname: Chow
authors.affiliation: Prince of Wales Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.|Department of Respiratory Medicine, Prince of Wales Hospital, Sydney, NSW, Australia.|Inflammation and Infection Research, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Thomas
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D001944:Breath Tests; D002118:Calcium / Q000097:blood / Q000378:metabolism; D045853:Exhalation; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D016676:Macrophages, Alveolar / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D017565:Sarcoidosis, Pulmonary / Q000378:metabolism*; D012720:Severity of Illness Index; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D014797:Vital Capacity
chemical_list: D015415:Biomarkers; D014409:Tumor Necrosis Factor-alpha; D002118:Calcium
keywords: Calcium; Conductivity; Exhaled breath condensate; Sarcoidosis; Tumour necrosis factor