Flagellin concentrations in expectorations from cystic fibrosis patients

The aim was to measure flagellin concentrations in the expectorations of CF patients and to examine whether there are correlations with the level of respiratory insufficiency and inflammation.

Sputum samples from 31 adult patients chronically colonized with P. aeruginosa were collected and analysed for their content of flagellin and IL-8. Clinical data were extracted from patient files.

Regardless of whether patients are colonized with mucoid strains or not, they carry clones of P. aeruginosa that express flagellin. While flagellin was present in airways of all of our CF patients, it is difficult to ascertain its contribution to inflammation (IL-8) and lung function deterioration.

This is the first demonstration that flagellin is present in the sputum of patients. Thus, attempts to down regulate inflammation by the use of TLR5 (flagellin receptor) antagonists remain a possibility. However, this result needs to be extended to a larger number of patients to validate it for future research on this subject.