2 days Ago By Aria Bendix
For many children diagnosed with asthma, pinpointing the particular nature of their case and finding appropriate treatment is far from simple. The lung disease, which affects more than 4.6 million children in the U.
S ., is often broken down into two categories. The first, known as “T2-high” asthma, is caused by inflammation from a particular type of immune system cell called T helper 2.
Until recent years, it was assumed to be the most common form. The second category, “T2-low” asthma, is essentially a catchall for other forms. It encompasses two subtypes — one involving less inflammation, and another characterized by inflammation from a different kind of T cell.
In some moderate or severe cases, figuring out which type of asthma a child has can help doctors match patients with proper treatment. But testing options have long been limited: Typically, doctors either draw blood to measure levels of immune cells or antibodies, or have children breathe into a mouthpiece to measure the nitric oxide in their breath. However, the tests aren’t always accurate, and they only detect T2-high asthma, and thus can’t differentiate between other subtypes.
So researchers at the University of Pittsburgh developed a more precise way to diagnose different asthma subtypes: collecting nasal swabs, then sequencing the RNA they contain. In people with two of the asthma subtypes, certain genes associated with inflammation are more highly expressed, so the researchers looked for those hallmarks. The third subtype was identified through the absence of those genetic hallmarks.
They describe the novel test in a paper published Thursday in the journal JAMA. The researchers used the test on more than 450 children and teens across three studies: one in Puerto Rico, one in Pittsburgh and one in both locations. The study participants were predominantly Puerto Rican or non-Hispanic Black.
The analysis showed that the nasal swabs could accurately diagnose several asthma subtypes. It also found that “T2-low” asthma — which has been associated with air pollution — was most common among the participants. Black and Puerto Rican children have higher rates of asthma and asthma-related deaths than white children in the U.
S. and are more likely to be exposed to asthma triggers like air pollution, dust or mold. The research builds on previous studies that have similarly detected asthma via nasal swabs.
The researchers hope the test can improve the process of matching kids to appropriate asthma treatments, said Dr. Juan Celedón, one of the paper’s authors and chief of pulmonary medicine at UPMC Children’s Hospital of Pittsburgh. “To me, this is a necessary first step for better personalized medicine,” he said.
The default treatment for any type of asthma is steroids, usually delivered through an inhaler. But in moderate or severe cases, that might not be enough. In the last decade, the Food and Drug Administration has approved several injectable or intravenous drugs for such patients.
These counteract molecules that trigger inflammation in the airways, but they are largely geared toward T2-high asthma. Celedón said the nasal swab test could help researchers identify people with T2-low asthma for the purpose of enrolling them in studies that test new treatments for that target. “Instead of treating most people the same, in a few years, we can treat you better according to the type of asthma you have,” he said.
The new findings are also noteworthy because the research involved children of color, who are often underrepresented in asthma studies, said Dr. Gurjit Hershey, director of the asthma research division at Cincinnati Children’s Hospital, who was not involved in the new paper. “Many studies have been done traditionally in white, European populations.
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To be able to have a study that really focuses on Puerto Rican and Black children is important,” she said. However, the technology isn’t ready to go mainstream. Celedón said it would need FDA approval before doctors could use it.
Plus, Hershey said, more research is needed to determine if a child’s asthma type is consistent throughout their youth, or if it changes in response to environmental exposures such as pollution or allergens. “The place to be cautious is, does it make sense to treat based on this?” she said, referring to the nasal swab test results. “We would have to do a study to figure that out.
” Dr. Jessica Hui, a pediatric allergist at National Jewish Health, a respiratory hospital in Denver, also cautioned that genetic sequencing is expensive, and the results would need to be analyzed by someone proficient in studying RNA. “It’s a very specialized type of analysis,” she said.
“It’s not like this is something we can implement immediately, but for sure it’s an exciting direction.”.
