Levels of neutrophil elastase and cathepsin B activities, and cystatins in human sputum: relationship to inflammation

Research output: Contribution to journalArticle


Sputum samples from 25 patients with bronchiectasis were assayed enzymatically for myeloperoxidase, neutrophil elastase and cathepsin B, and immunologically for cystatin A, cystatin B, cystatin C, cystatin S and kininogen. High myeloperoxidase and neutrophil elastase levels were found in those sputum samples that were assessed visually to be purulent. These samples were also found to contain high levels of cathepsin B activity and cystatin A, but low levels of cystatin S and of the most effective cathepsin B inhibitor, cystatin C. In contrast, sputum samples that were low in myeloperoxidase and neutrophil elastase activities had low levels of cathepsin B and cystatin A, but high cystatin C and S levels. It is concluded that cathepsin B activity in sputum is positively correlated with the degree of inflammation and neutrophil recruitment. Although this may be due in part to reduced amounts of cathepsin B inhibitors, particularly cystatin C, theoretical considerations suggest that factors other than the gross level of inhibitors must be involved in the control of cathepsin B activity.


Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Pharmacology and Toxicology
  • Medicinal Chemistry


  • agr2-macroglobulin, bronchiectasis, myeloperoxidase, neutrophil degranulation
Original languageEnglish
Pages (from-to)509-516
JournalScandinavian Journal of Clinical & Laboratory Investigation
Issue number5
Publication statusPublished - 1990
Publication categoryResearch