FRIDAY, March 20 (HealthDay News) -- White blood cells called neutrophils play an important role in the severe lung damage suffered by cystic fibrosis patients, according to U.S. researchers.

Their findings may open up new targets for treatment of CF, which affects about 30,000 people in the United States.

"Cystic fibrosis patients have a problem with turning down the inflammatory response in the lungs. We've found that patients' neutrophils become kind of schizophrenic, doing a number of things that are opposite to the textbook view of neutrophils' role," senior study author Rabindra Tirouvanziam, an instructor in pediatric pulmonary medicine at Stanford University Medical Center and Lucile Packard Children's Hospital, said in a university news release.

It was long believed that neutrophils attacked and destroyed bacteria that became trapped in the excess mucus that collects in the lungs of CF patients. But something goes wrong, and neutrophils quickly die in the lungs, releasing tissue-destroying enzymes as they do.

However, when Tirouvanziam and colleagues analyzed fresh neutrophils from CF patients' sputum, they found that signals from the patients' lung tissue were reprogramming live neutrophils with conflicting messages that "are messing them up completely."

As a result, the neutrophils may release large amounts of an enzyme called human neutrophil elastase, which destroys the elastic fiber of the lungs, the researchers said. In healthy people, neutrophils never release this enzyme into nearby tissue.

The study was published in this week's online issue of the Proceedings of the National Academy of Sciences.

• More News on Cystic Fibrosis

Related MedlinePlus Pages:

• Cystic Fibrosis