People acutely ill with asthma have abnormally high, but reversible, acidity in their lungs. This unexpected finding may lead to improved therapies for treating the disease and new ways to predict an attack, says study coauthor Benjamin Gaston of the University of Virginia Health System in Charlottesville.
He and his colleagues collected moisture from volunteers’ breath and measured its acidity. The average pH value among 22 asthma patients who had recently experienced difficulty breathing was 5.2, the researchers report in the March American Journal of Respiratory And Critical Care Medicine.
In contrast, lung moisture from people who aren’t asthmatic had an average pH of 7.65, and that from people whose asthma symptoms were under control was pH 7.8. A pH below 7 is acidic, and a pH of 5.2 “is not compatible with normal lung function,” says Jonathan S. Stamler of Duke University Medical Center in Durham, N.C.
Low pH values may serve as “an early warning sign of an impending asthma attack,” Gaston speculates, perhaps enabling people to take medications early, when they are most likely to be effective.
If confirmed in larger studies, the findings may have implications for treatment. Just as antacids—which neutralize excess stomach acid—can prevent stomach pain, drugs that normalize the pH of an asthmatic’s lungs may reverse symptoms such as wheezing and inflammation, Stamler says.