Rapid Nasal Swab Test Detects Asthma Type in Kids

It is crucial to develop new therapies to address the specific needs of these young patients. Traditionally, asthma has been categorized into endotypes: T2-high or T2-low, based on the levels of T helper 2 (T2) inflammation. More recently, the T2-low category has been further divided into two distinct subtypes: T17-high, characterized by increased T helper 17 (T17) inflammation and low T2 inflammation, and low-low, marked by low levels of both T2 and T17 inflammation. Given the variability of asthma, which is driven by different immune cells and responds to treatments in diverse ways, the first step toward improving therapies is accurate endotype diagnosis. Traditionally, diagnosing endotype involves a genetic analysis of lung tissue obtained through a bronchoscopy, a procedure performed under general anesthesia. However, for children, particularly those with milder asthma, this invasive approach is often impractical and unethical. As a result, clinicians have had to rely on less accurate tools, such as immune markers in the blood, lung function tests, and allergy presence.

Now, researchers at the University of Pittsburgh (Pittsburgh, PA, USA) have developed a non-invasive nasal swab test for children to diagnose specific asthma subtypes or endotypes. This approach promises to enable clinicians to prescribe treatments more precisely and could pave the way for research into therapies for less-studied asthma types that have been difficult to diagnose accurately. The study, published in JAMA, analyzed data from three independent U.S.-based studies, focusing on Puerto Rican and African American youth, who experience higher asthma rates and mortality compared to non-Hispanic white children.

The researchers collected nasal samples from 459 children across the three studies and analyzed the expression of eight T2 and T17 signature genes. As anticipated, the nasal swab analysis revealed the asthma endotype for each patient. Across the studies, 23% to 29% of participants were classified as T2-high, 35% to 47% as T17-high, and 30% to 38% as low-low endotype. While biologic drugs that target immune cells driving T2-high asthma are available, there are no current biologic treatments for T17-high and low-low endotypes. With the availability of this simple nasal swab test to detect other endotypes, the focus can now shift on developing biologics for T17-high and low-low disease. This rapid diagnostic test could also accelerate progress in other areas of asthma research.

“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. Before puberty, asthma is more common in boys, but the incidence of asthma goes up in females in adulthood,” said senior author Juan Celedón, M.D., Dr. P.H., professor of pediatrics at Pitt. “Is this related to endotype? Does endotype change over time or in response to treatments? We don’t know. But now that we can easily measure endotype, we can start to answer these questions.”