Clinical Newswire Sept. 28, 2003 (VIENNA, Austria) - The use of exhaled biomarkers will allow the simple, non-invasive evaluation of a number of respiratory diseases according to lung disease experts who spoke at the 13th Annual Congress of the European Respiratory Society (ERS) held in Vienna, Austria.
Until now, assessment of diseases such as asthma has often involved invasive tests such as bronchoscopy or bronchial biopsy. However, the use of exhaled air to evaluate gases such as nitric oxide (NO) or exhaled breath condensate (EBC) to measure disease markers in fluid lining the airway is now close to entering standard clinical practice with the release of two statements by the ERS.
In 2002 the ERS issued a joint statement with the American Thoracic Society (ATS) on the measurement of exhaled NO in children, which aimed to standardize the measurement of this marker. NO is a well validated marker of airway inflammation. The accurate measurement of airway inflammation provides a useful tool in the diagnosis of asthma, the prediction of asthma exacerbations and the potential to guide asthma therapy.
Currently, treatment for asthma is commonly based on symptoms or lung function. However, inhaled steroids, the most effective treatment for childhood asthma, treat airway inflammation, which does not correlate well with symptoms. Therefore, objective assessment of airway inflammation could provide an important indication of which patients need treatment. Two studies have shown proven this concept, showing that the number of exacerbations are significantly reduced if treatment is guided by airway inflammation rather than symptoms.
“If you assess inflammation and determine the treatment on the basis of this inflammation you are treating the patient much better, and there will be less asthma attacks” said Dr. Johan de Jongste, Professor of Pediatric Respiratory Medicine at Erasmus University Medical Center, Rotterdam, The Netherlands. He also pointed out the utility of this test for diagnosis of asthma, saying “this is the first test that, with a single measurement, in an untreated child, will have a 98% sensitivity for excluding asthma.”
An ERS/ATS joint task force is now about to release recommendations for the standardization of EBC. Like the mist on the inside of your windscreen on a cold day, EBC provides a noninvasive sample of the fluid lining the airway. Currently a research tool, the upcoming recommendations will outline a standardized approach to collection of samples. EBC may enable the measurement of a number of markers such as leukotrienes, interleukins, NO-related and cyclooxygenase products which may be associated with a number of respiratory diseases such as COPD, bronchiectasis, ARDS, lung cancer and pneumonia.
Giving one possible application of this method, Dr. Eugenio Baraldi from the University of Padova, Italy said that “using EBC it is possible to measure the inflammatory mediators leukotrienes. So we have the potential to predict which patient will respond to antileukotriene therapy.”
While there are several methodological issues to be resolved before EBC is used in routine clinical practice, Dr. Baraldi stated that exhaled NO is now ready to be used to assess asthma control and medication response in the clinical setting. Taking a view of the future, Professor Friedrich Kummer, who was Chair of the ERS Congress and is from Vienna, Austria said “I envisage an exhaled air condensator that will allow general practioners (in their office) to monitor their patients on the basis of inflammation and infection.” |
