October 6, 2010

New Plan of Attack Against Cystic Fibrosis

(Ivanhoe Newswire) -- Roughly 30,000 children in the U.S. are affected by cystic fibrosis (CF) every year. It is a chronic disease that affects the lungs and digestive tract. People with CF typically only live to their mid 30s. Scientists have discovered bacteria that are linked to exacerbations, or worsening, of CF and now they are using the new information to make treatment plans against the bacteria.

"Our study showed that chronic infection with S. maltophilia, which was previously not regarded as prognostically significant, may have a real impact on the progression of CF in patients," Valerie Waters, M.D., assistant professor of infectious diseases at the Hospital for Sick Children in Toronto was quoted as saying. "We hope that this study is a starting point for further research, which may point to therapeutic possibilities associated with controlling these infections."

CF is an inherited chronic disease that is characterized by thick, sticky mucus in the lungs and digestive tract, causing chronic infections and in turn a short-lived life. Over time, exacerbations in CF can lead to permanent loss of lung function, only driving the progression of this deadly disease.

CF patients are living longer than ever before, and due to this respiratory tract colonization and infection with multi-drug resistant pathogens are increasing in frequency. Among these, S. maltophilia is particularly common and is isolated from the respiratory tract of up to a third of CF patients. To assess whether S. maltophilia represented a true infection, rather than merely a colonizing organism, and whether it had an impact on the progression of disease, Dr. Waters and colleagues performed a two-stage study. In the first stage, they wanted to determine if S. maltophilia generated an immune response in CF patients. In the second stage, they retrospectively followed almost 700 CF patients for 12 years to determine whether chronic infection with S. maltophilia was independently associated with an increased risk of exacerbation or lowered lung function.

They found that antibody levels to S. maltophilia flagellin, were about two times higher in chronically infected patients compared to those who were never infected, indicating a specific immune response and a true infection, rather than colonization. The increased antibody levels were also associated with lower lung function, as measured by FEV1 (forced expiratory volume in one second.)

Furthermore, they found that patients with chronic S. maltophilia infections had a 63 percent greater risk of exacerbations than those who had never been infected. "This is the first study to our knowledge that demonstrates CF patients with chronic S. maltophilia infection have a specific immune response, which is in turn associated with lower lung function," said Dr. Waters. "There have been few studies that investigate the effect of S. maltophilia infection on clinical outcomes; those that have been short-term and have not shown any significant clinical effects of the infection. This study, however, points to the possibility that chronic infection has a real and significant clinical impact on these patients."

"It is crucial that we look to determine whether chronic S. maltophilia infection directly results in the worsening of lung function," Dr. Waters said. "We plan to investigate the effects of chronic S. maltophilia during pulmonary exacerbations in future studies."

SOURCE: American Journal of Respiratory and Critical Care Medicine, published online October 2010