title: Exhaled Hydrogen Sulfide Predicts Airway Inflammation Phenotype in COPD.
abstract: BACKGROUND
  The role of exhaled H2S as a marker of airway inflammation and its relationship with COPD severity remain to be determined.
  
  
  METHODS
  Airway inflammation was classified in 77 COPD subjects based on the presence of inflammatory cells in induced sputum. We investigated the association between disease phenotype and exhaled H2S, lung function, and plasma levels of several inflammatory factors, including tumor necrosis factor alpha, interleukin-8, and leukotriene B4.
  
  
  RESULTS
  In total, 33.77% of enrolled COPD subjects were diagnosed with eosinophilia. These subjects had a longer disease course, smoked fewer cigarettes, and experienced more frequent exacerbation events before study enrollment. However, they also had worse lung function and larger residual volume, they demonstrated greater changes in FEV1 following bronchodilator inhalation. Although levels of plasma inflammatory factors did not significantly differ between subjects with and without eosinophilia, subjects without eosinophilia had significantly higher levels of exhaled H2S (9.19±2.74 vs 7.24±1.68 parts per billion, P=.01). Furthermore, exhaled H2S levels were negatively correlated with induced sputum eosinophils (r=-0.45, P=.05), and positively correlated with inspiratory capacity in COPD subjects (r=0.51, P=.026), but did not correlate significantly with plasma inflammatory factors. A cut-off value of 7.10 parts per billion of exhaled H2S predicted a non-eosinophilic phenotype with 68.6% sensitivity and 77.9% specificity.
  
  
  CONCLUSIONS
  Exhaled levels of H2S were lower in subjects with eosinophilia. Increased levels of exhaled H2S predicted a non-eosinophilic phenotype in our study population.
authors.affiliation: Department of Respiratory Diseases, Peking University Third Hospital.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Respiratory Diseases, Beijing Tongren Hospital, Beijing, People's Republic of China.
authors.forename: Xinmao
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Respiratory Diseases, Peking University Third Hospital medscizj@126.com.
authors.forename: Yahong
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Respiratory Diseases, Peking University Third Hospital.
authors.forename: Wanzhen
authors.initials: W
authors.lastname: Yao
mesh_terms: D000368:Aged; D019540:Area Under Curve; D015415:Biomarkers / Q000032:analysis; D001944:Breath Tests; D004802:Eosinophilia / Q000150:complications / Q000378:metabolism*; D004804:Eosinophils; D045853:Exhalation; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D006862:Hydrogen Sulfide / Q000032:analysis*; D007249:Inflammation / Q000145:classification* / Q000150:complications / Q000378:metabolism*; D007320:Inspiratory Capacity; D016209:Interleukin-8 / Q000097:blood; D007975:Leukotriene B4 / Q000097:blood; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000503:physiopathology*; D012372:ROC Curve; D012115:Residual Volume; D013183:Sputum / Q000166:cytology; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D015415:Biomarkers; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha; D007975:Leukotriene B4; D006862:Hydrogen Sulfide
keywords: airway inflammation phenotype; chronic obstructive pulmonary disease; eosinophilia; hydrogen sulfide