Concentration of the antibacterial precursor thiocyanate in cystic fibrosis airway secretions

Free Radic Biol Med. 2011 May 1;50(9):1144-50. doi: 10.1016/j.freeradbiomed.2011.02.013. Epub 2011 Feb 18.


A recently discovered enzyme system produces antibacterial hypothiocyanite (OSCN(-)) in the airway lumen by oxidizing the secreted precursor thiocyanate (SCN(-)). Airway epithelial cultures have been shown to secrete SCN(-) in a CFTR-dependent manner. Thus, reduced SCN(-) availability in the airway might contribute to the pathogenesis of cystic fibrosis (CF), a disease caused by mutations in the CFTR gene and characterized by an airway host defense defect. We tested this hypothesis by analyzing the SCN(-) concentration in the nasal airway surface liquid (ASL) of CF patients and non-CF subjects and in the tracheobronchial ASL of CFTR-ΔF508 homozygous pigs and control littermates. In the nasal ASL, the SCN(-) concentration was ~30-fold higher than in serum independent of the CFTR mutation status of the human subject. In the tracheobronchial ASL of CF pigs, the SCN(-) concentration was somewhat reduced. Among human subjects, SCN(-) concentrations in the ASL varied from person to person independent of CFTR expression, and CF patients with high SCN(-) levels had better lung function than those with low SCN(-) levels. Thus, although CFTR can contribute to SCN(-) transport, it is not indispensable for the high SCN(-) concentration in ASL. The correlation between lung function and SCN(-) concentration in CF patients may reflect a beneficial role for SCN(-).

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Animals, Newborn
  • Anti-Bacterial Agents / metabolism*
  • Bodily Secretions
  • Bronchi / metabolism
  • Cells, Cultured
  • Colony Count, Microbial
  • Cystic Fibrosis / genetics
  • Cystic Fibrosis / metabolism*
  • Cystic Fibrosis / microbiology
  • Cystic Fibrosis / physiopathology
  • Cystic Fibrosis Transmembrane Conductance Regulator / genetics
  • Cystic Fibrosis Transmembrane Conductance Regulator / metabolism*
  • Epithelial Cells / metabolism
  • Gene Expression
  • Homozygote
  • Humans
  • Microbial Sensitivity Tests
  • Nasal Cavity / metabolism
  • Oxidation-Reduction
  • Staphylococcus aureus / growth & development
  • Swine
  • Thiocyanates / metabolism*
  • Trachea / metabolism


  • Anti-Bacterial Agents
  • Thiocyanates
  • cystic fibrosis transmembrane conductance regulator delta F508
  • Cystic Fibrosis Transmembrane Conductance Regulator
  • hypothiocyanite ion
  • thiocyanate