New Asthma Biomarkers Discovered
People with asthma have telltale molecules circulating in their blood, say researchers at Penn State College of Medicine. According to a release from Penn on April 13th 2016, the discovery could lead to the first diagnostic blood test for asthma, as well as more targeted treatments for the condition. The results were published in The Journal of Allergy and Clinical Immunology.
There are currently no definitive diagnostic tests for asthma, a common chronic inflammatory lung disease that affects 25 million Americans.
The release quotes Faoud T. Ishmael, associate professor of medicine and biochemistry and molecular biology, as saying, “Right now, we diagnose asthma based on someone’s history and breathing tests — and both of those have limitations.”
There are also several sub-types of the condition, such as allergic or non-allergic asthma or the presence or absence of immune cells called eosinophils. The different variations make asthma harder to treat.
Some asthma patients do not find relief from inhaled corticosteroids, the mainstay of asthma treatment. Asthma sub-types could play a role in this but “there’s not a good way right now to understand what those different sub-types are,” Ishmael said. “This goes back to the underlying issue, which is that we don’t have a good blood test to tell us what’s really going on in the lungs.”
To that end, Ishmael set his sights on microRNAs (miRNAs) — molecules that help regulate gene expression. miRNAs were once considered “junk DNA,” but over the past decade, scientists have come to realize that they play an important role in many human diseases.
More than 150 miRNAs can be identified in blood, and they are beginning to be used as molecular footprints to diagnose and characterize diseases such as cancer.
“The role of miRNAs in asthma is not well understood, although it looks as though these molecules play very important roles in inflammation and in immune responses,” Ishmael said.
His team previously showed that miRNAs in the lungs and blood can be used as asthma biomarkers, and that they may regulate proteins involved in allergic inflammation. However, important questions remained. For example, would people with asthma have different miRNA than people with other related conditions?
In their new study, the researchers looked at miRNAs in the blood of 79 people. The subjects included asthmatics, people with nasal allergies but no asthma and people with no nasal allergies and no asthma.
Narrowing in on 30 miRNAs important in allergies and asthma, the researchers found different expression patterns among the three groups. Based on these patterns, they were able to predict with 91 percent accuracy whether or not a person had asthma, opening the door to the development of a diagnostic blood test.