Mario Castro, MD, MPH: Defining Severe Asthma Biomarkers

Strategic Alliance Partnership | <b>American Lung Association</b>

Dr. Castro defines type 2 inflammation and the complications surrounding severe asthma, as well as several biomarkers including IgE levels, blood eosinophils, and exhaled nitric oxide.

With Asthma Peak Week rapidly approaching, conversations are once again being held by clinicians and patients alike on what the appropriate measures for asthma management are.

Patients with severe asthma and type 2 inflammation are of particular concern, especially as exposure rates begin to climb in the coming season.

Luckily, treatments for these patient groups exist.

In the September 2021 episode of Lungcast, Al Rizzo, MD, Chief Medical Officer of the American Lung Association (ALA), discusses severe asthma biologic therapy with Mario Castro, MD, MPH.

Castro is the Chief of Pulmonary, Critical Care and Sleep Medicine; Vice-Chair for Clinical and Translational Research; and Director of Rainbow Clinical and Translational Science Unit, Frontiers at the University of Kansas School of Medicine.

“When we talk about patients with severe asthma, we use a combination of having an underlying diagnosis of asthma together with a patient that is either on high dose therapy with corticosteroids with a lone acting controller, and requires that treatment to retain their control, or despite that are not achieving control,” Castro said.

He added that patients with severe asthma represent 5%-10% of the population of people with asthma, and that clinicians have been able to advance therapies for these patients by understanding the phenotype or characteristics that lead to their underlying disease.

Castro and his colleagues have proposed 4 phenotypes of asthma: T2 driven disease or non-T2 driven disease.

“This T2 phenotype has really helped us advance targeted therapy for severe asthma,” Castro said. “So, we can now target those particularly T2 cytokines and we can abdicate that inflammation and lead to improved control in biologic therapy.”

Rizzo and Castro discussed several biomarkers that are used to treat inflammation in patients with severe asthma, including IgE levels, blood eosinophils, and exhaled nitric oxide.

For patients with elevations in their T2 levels, IgE are used to characterize a patients’ allergic status, and exhaled nitric oxide, commonly found in allergy and pulmonary offices, has been used to manage airway epiphyllum.

However, the most prominent biomarker are blood eosinophils.

“Blood eosinophils have really helped us advance our understanding of eosinophilic asthma, which is a subset of T2 inflammation,” Castro said.

Blood eosinophils have been considered a prognostic biomarker and a biomarker for therapy response predictor, and patients with high blood eosinophil have an increased risk of downstream events, like exacerbation and reduction in lung function. They have been known to respond better to corticosteroids.

Lungcast is a monthly respiratory health podcast series from the ALA, produced by HCPLive.

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