A new nasal swab test developed at the University of Pittsburgh could help medical researchers better understand subtypes of childhood asthma. The test is designed to be a tool to specify treatments for lesser-studied asthma types, which have historically been difficult to diagnose.
“Asthma is a highly variable disease,” said senior author Dr. Juan Carlos Celedón, professor of pediatrics at Pitt and chief of pulmonary medicine at UPMC Children’s Hospital of Pittsburgh. “And it disproportionately affects Black and Puerto Rican children, so it’s essential that we develop new therapies to better treat these young patients.”
Pitt researchers tested nearly 460 children across three studies, focusing on Black and Puerto Rican kids, who are more likely to experience asthma. The findings were announced in a paper published in the Journal of the American Medical Association Thursday.
Asthma is an umbrella diagnosis for several endotypes — or subtypes — of the condition based on immune cells and the amount of inflammation present. For doctors to precisely diagnose an asthma endotype, they must retrieve a lung tissue sample which requires a patient to undergo general anesthesia. The testing procedure can be costly, it isn’t typically used for milder conditions, and it can’t diagnose all endotypes of asthma.
Without a tissue sample, doctors must rely on imperfect tools such as blood samples, lung function analysis and allergy testing to treat patients.
But the rapid test designed by Celedón’s team proved capable of diagnosing the three major endotypes of asthma. Researchers scraped the lining of the nose with a small, spoon-shaped swab and analyzed the genetic sample to determine an asthma endotype. The test is similar to the COVID-19 swab but does not require the swab to reach the back of the nose to collect a sample. Celedón said most kids tolerated the test well.
Researchers tested children at UPMC Children’s Hospital in Pittsburgh and the University of Puerto Rico Medical Center. Puerto Ricans experience the highest rates of asthma in the United States and comprise the largest share of U.S. families below the poverty level.
Children growing up in the Pittsburgh region are at greater risk of developing asthma compared to other parts of the country. And kids who live near industrial sites or highways are nearly three times more likely to suffer from asthma.
Black children in the U.S. are also disproportionately affected by asthma, with 12% of kids affected by the condition, according to the Centers for Disease Control and Prevention. Often, Black children are statistically more likely to live in areas with high industrial pollution or in rental housing with mold or other asthmatic triggers. Distrust in doctors or otherwise poor medical care can lead to more severe cases of asthma: Black children are seven times more likely to die from asthma compared to their white counterparts, according to the National Library of Medicine.
But not much is known about whether varying asthma endotypes play a role in the disparity.
Celedón said the swabs could also be used to learn more about how age and sex play a role in asthma. Men are more likely to develop asthma in childhood, while women are more likely to suffer from the condition overall. Medical data suggests women are more likely to develop asthma later in life and their cases tend to be more severe.
“One of the million-dollar questions in asthma is why some kids get worse as they enter puberty, some stay the same and others get better,” Celedón said. “Before puberty, asthma is more common in boys, but the incidence of asthma goes up in females in adulthood.”
The reason behind these variables is something Celedón hopes the nasal swab can help to answer.
“Do these endotypes change over time?” he asked. “[And] It’s very possible that people may have more than one endotype.”
Beyond better understanding the different types of asthma, Celedón said the nasal swab tests could also lead to better and more specified treatments.
For example, obese patients often suffer from severe asthma that is more difficult to control compared to leaner patients. While in some cases the severity is the result of health conditions associated with obesity, like sleep apnea or hypertension, Celedón said an oversimplification of diagnosing asthma may play a role in this disparity.
“If you’re obese and you have asthma, you’re less likely to respond to commonly used treatments,” Celedón said. “One of the reasons might be that they have a different endotype.”
But the handful of drugs used for severe asthma cases are not effective against lesser-studied asthma subtypes. Injectable medicines can improve the condition of people with asthma associated with allergies, but not for those with asthma types not associated with allergens.
Celedón said allergen-related asthma treatment has progressed “because better markers have propelled research on this endotype.”
“But now that we have a simple nasal swab test to detect other endotypes, we can start to move the needle on developing [precision treatments],” he said.
