Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Jul;9(7):2680-2688.e7.
doi: 10.1016/j.jaip.2021.02.059. Epub 2021 Mar 18.

Cluster Analysis of Inflammatory Biomarker Expression in the International Severe Asthma Registry

Affiliations
Free article

Cluster Analysis of Inflammatory Biomarker Expression in the International Severe Asthma Registry

Eve Denton et al. J Allergy Clin Immunol Pract. 2021 Jul.
Free article

Erratum in

  • Correction.
    [No authors listed] [No authors listed] J Allergy Clin Immunol Pract. 2021 Nov;9(11):4182. doi: 10.1016/j.jaip.2021.09.006. J Allergy Clin Immunol Pract. 2021. PMID: 34749955 No abstract available.

Abstract

Background: Allergy, eosinophilic inflammation, and epithelial dysregulation are implicated in severe asthma pathogenesis.

Objective: We characterized biomarker expression in adults with severe asthma.

Methods: Within the International Severe Asthma Registry (ISAR), we analyzed data from 10 countries in North America, Europe, and Asia, with prespecified thresholds for biomarker positivity (serum IgE ≥ 75 kU/L, blood eosinophils ≥ 300 cells/μL, and FeNO ≥ 25 ppb), and with hierarchical cluster analysis using biomarkers as continuous variables.

Results: Of 1,175 patients; 64% were female, age (mean ± SD) 53 ± 15 years, body mass index (BMI) 30 ± 8, postbronchodilator forced expiratory volume in 1 second (FEV1) predicted 72% ± 20%. By prespecified thresholds, 59% were IgE positive, 57% eosinophil positive, and 58% FeNO positive. There was substantial inflammatory biomarker overlap; 59% were positive for either 2 or 3 biomarkers. Five distinct clusters were identified: cluster 1 (61%, low-to-medium biomarkers) comprised highly symptomatic, older females with elevated BMI and frequent exacerbations; cluster 2 (18%, elevated eosinophils and FeNO) older females with lower BMI and frequent exacerbations; cluster 3 (14%, extremely high FeNO) older, highly symptomatic, lower BMI, and preserved lung function; cluster 4 (6%, extremely high IgE) younger, long duration of asthma, elevated BMI, and poor lung function; cluster 5 (1.2%, extremely high eosinophils) younger males with low BMI, poor lung function, and high burden of sinonasal disease and polyposis.

Conclusions: There is significant overlap of biomarker positivity in severe asthma. Distinct clusters according to biomarker expression exhibit unique clinical characteristics, suggesting the occurrence of discrete patterns of underlying inflammatory pathway activation and providing pathogenic insights relevant to the era of monoclonal biologics.

Keywords: Biomarkers; Eosinophils; Fractional exhaled nitric oxide; Immunoglobulin E; Severe asthma.

PubMed Disclaimer

Comment in

Publication types