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Non-Invasive Nasal Swab Can Diagnose Specific Asthma Endotype in Young Patients
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Key Takeaways
- A nasal swab test can diagnose specific asthma subtypes in children, aiding in precise treatment selection.
- The study focused on Puerto Rican and African American youths, who are disproportionately affected by asthma.
The investigators note that the test can allow health care professionals to more accurately prescribe medication or treatments.
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Researchers developed a non-invasive nasal swab test for pediatric patients with asthma to diagnose their disease’s specific subtype or endotype. The investigators note that using this test can help health care professionals more accurately and efficiently prescribe suitable treatments for patients.1 Additionally, they note that study findings published in JAMA can contribute to future research on lesser-studied asthma types, which have previously shown to be difficult.1,2
The research published in JAMA was a cross-sectional analysis of 3 studies that included nasal epithelial samples from youths aged 6 to 20 years with asthma. The study populations included both Puerto Rican and African American patients because these subpopulations are more likely to be affected by asthma.1
“Asthma is the most common chronic disease of childhood, and it disproportionately affects Black and Puerto Rican children, so it’s essential that we develop new therapies to better treat these young patients,” senior author Juan Celedón, MD, DrPH, professor of pediatrics at the University of Pittsburgh and chief of pulmonary medicine at UPMC Children’s Hospital of Pittsburgh, said in a news release. “Because asthma is a highly variable disease with different endotypes, which are driven by different immune cells and respond differently to treatments, the first step toward better therapies is accurate diagnosis of endotype.”2
According to the investigators, asthma has traditional been classified either as T helper 2 (T2)-high or T2-low depending on the amount of T2 inflammation present in the individual patient. Further, T2-low has recently been split into 2 endotypes: T helper 17 (T17)-high, which has less T2 inflammation and more T17 inflammation; and low-low, which has low levels of both inflammation types. To properly diagnoses endotype, a genetic analysis of lung tissue sample—acquired by a bronchoscopy—is performed. For children, and especially those with less severe asthma, this can be an invasive procedure, so other diagnosis methods are needed.1,2
“These tests allow us to presume whether a child has T2-high disease or not. But they are not 100% accurate, and they cannot tell us whether a child has T17-high or low-low disease. There is no clinical marker for these 2 subtypes,” said Celedón in the news release. “This gap motivated us to develop better approaches to improve the accuracy of asthma endotype diagnosis.”2
For the study, the investigators assessed the nasal epithelial transcription profiles of patients with asthma. The primary outcome was profiles of 3 T2 and 5 T17 pathway genes. Clinical characteristics, total and allergen-specific immunoglobulin E (IgE), blood eosinophils, and lung function were also assessed and compared across profiles in the 3 studies.1
Despite prior evidence that T2-high is considered the most common asthma endotype in school-aged children with asthma, the current study found that T2-low asthma endotypes—including T17-high and low-low—were more prevalent among the evaluated patients.1 Across the 3 studies, T2-high was present in approximately 23% to 29% of participants, T17-high in 35% to 47%, and low-low in 30% to 38%.1
“We have better treatments for T2-high disease, in part, because better markers have propelled research on this endotype,” said Celedón. “But now that we have a simple nasal swab test to detect other endotypes, we can start to move the needle on developing biologics for T17-high and low-low disease.”2
Additionally, in each study, the median total IgE and blood eosinophils for the T2-high profile were higher (IgE: 584-869 IU/mL; eosinophils: 343-560 cells/mL) than the T2-low profiles (IgE: 105-382 IU/mL; eosinophils: 164-413 cells/mL). Of the participants in all profiles, at least 50% had 1 or more positive allergen-specific IgEs. The T17-high profile was also associated with interleukin (IL)-17 and neutrophil signaling pathways, whereas the T2-high profile was associated with IL-13 signaling pathways.1
“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 Celedón. “Is this related to endotype? Does endotype change over time or in response to treatments?…now that we can easily measure endotype, we can start to answer these questions.”2
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