The immune system responds to infections in the lungs by recruiting neutrophils, a group of immune cells that are responsible for recognizing and eliminating pathogens, to the site of infection. In addition to killing infectious pathogens, neutrophils also drive inflammation, which can lead to poor lung function and sometimes fatal complications.
In this issue of the Journal of Clinical Investigation, researchers led by Julia Klesney-Tait at the University of Iowa examined how the loss of the inflammatory protein TREM-1 affected the survival of mice infected with pneumonia.
Though they had expected loss of TREM-1 to increase survival by reducing inflammation, Klesney-Tait and colleagues found that mice lacking TREM-1 had increased inflammation and were more likely to die from lung infection.
Examination of the lungs of the infected mice showed that neutrophils lacking TREM-1 were unable to migrate to the site of infection. This study identified an unexpected role for TREM-1 in neutrophil migration and indicates that therapeutics targeting TREM-1 may have unintended effects.
University of Iowa Carver College of Medicine, Iowa City, IA, USA
Transepithelial migration of neutrophils into the lung requires TREM-1
Journal of Clinical Investigation Dec. 17, 2012