Neutrophil elastase in respiratory epithelial lining fluid of individuals with cystic fibrosis induces interleukin-8 gene expression in a human bronchial epithelial cell line

J Clin Invest. 1992 May;89(5):1478-84. doi: 10.1172/JCI115738.


The respiratory manifestations of cystic fibrosis (CF) are characterized by neutrophil-dominated airway inflammation. Since a variety of inflammatory stimuli are capable of inducing bronchial epithelial cells to express the gene for IL-8, a cytokine that attracts and activates neutrophils, mediators in respiratory epithelial lining fluid (ELF) of CF individuals might induce IL-8 production by epithelial cells, thus recruiting neutrophils to the airways. BET-1A human bronchial epithelial cells at rest or incubated with normal ELF showed little IL-8 gene expression, but after incubation with CF ELF, a marked increase in IL-8 transcript levels was observed. CF ELF contained high levels of neutrophil elastase (NE) and various serine protease inhibitors prevented CF ELF from inducing IL-8 gene expression in BET-1A cells, suggesting that NE was the dominant inducer for IL-8 production in CF ELF. The addition of purified NE caused BET-1A cells to increase IL-8 gene transcription with accumulation of mRNA transcripts and to release IL-8-like neutrophil chemotactic activity. These observations suggest a self-perpetuating inflammatory process on the CF bronchial surface where NE released by neutrophils induced the bronchial epithelium to secrete IL-8, which in turn recruits additional neutrophils to the bronchial surface.

MeSH terms

  • Base Sequence
  • Bronchi / physiopathology*
  • Bronchoalveolar Lavage Fluid
  • Cell Line
  • Chemotaxis, Leukocyte
  • Cystic Fibrosis / physiopathology*
  • Epithelium / physiology
  • Gene Expression
  • Humans
  • Interleukin-8 / genetics*
  • Molecular Sequence Data
  • Neutrophils / enzymology*
  • Oligodeoxyribonucleotides / chemistry
  • Pancreatic Elastase / metabolism*
  • Polymerase Chain Reaction
  • RNA, Messenger / genetics


  • Interleukin-8
  • Oligodeoxyribonucleotides
  • RNA, Messenger
  • Pancreatic Elastase