The lungs of patients with cystic fibrosis (CF) have high levels of proteases that disable immune cells, a finding that helps explain why those with the disorder fail to clear the airways of infection by Pseudomonas aeruginosa and other bacteria,
according to a team of German scientists (Hartl D et al. Nat Med. 2007;13:1423-1430).
The researchers found that in healthy persons, IL-8 promotes bacterial killing by neutrophils via the chemokine receptor CXCR1,
but in patients with CF, high levels of proteases in the lungs of these individuals cleave CXCR1, hindering neutrophils' ability to kill bacteria. In addition, the cleaved fragments of CXCR1 stimulate further secretion of IL-8.
Stephenson J. Cystic Fibrosis and Infections. JAMA. 2008;299(3):279. doi:10.1001/jama.299.3.279-b