Abstract
The severe bronchiolitis endotype characterized by a high abundance of H. influenzae, high proportion of RV-A and RV-C infections, and high asthma genetic risk had a significantly higher risk for developing asthma.
Background Infants with bronchiolitis are at increased risk for developing asthma. Growing evidence suggests bronchiolitis is a heterogeneous condition. However, little is known about its biologically distinct subgroups based on the integrated metagenome and asthma genetic risk signature and their longitudinal relationships with asthma development.
Methods In a multi-center prospective cohort study of infants with severe bronchiolitis (i.e., bronchiolitis requiring hospitalization), we profiled nasopharyngeal airway metagenome and virus at hospitalization, and calculated the polygenic risk score of asthma. Using similarity network fusion clustering approach, we identified integrated metagenome-asthma genetic risk endotypes. We also examined their longitudinal association with the risk of developing asthma by age six years.
Results Of 450 infants with bronchiolitis (median age, 3 months), we identified five distinct endotypes—characterized by their nasopharyngeal metagenome, virus, and asthma genetic risk profiles. Compared with endotype A infants (who clinically resembled “classic” bronchiolitis), endotype E infants (characterized by a high abundance of H. influenzae, high proportion of RV-A and RV-C infections, and high asthma genetic risk) had a significantly higher risk for developing asthma (35.9% versus 16.7%; ORadj, 2.24; 95%CI, 1.02–4.97; p=0.046). The pathway analysis showed that endotype E had enriched microbial pathways (e.g., glycolysis, L-lysine, arginine metabolism) and host pathways (e.g., IFNs, IL-6/JAK/STAT3, fatty acids, MHC, and immunoglobin-related) (FDR<0.05). Additionally, endotype E had a significantly higher proportion of neutrophils (FDR<0.05).
Conclusion In this multi-center prospective cohort study of infant bronchiolitis, the clustering analysis of integrated-omics data identified biologically distinct endotypes with differential risks for developing asthma.
Footnotes
This manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.
Conflict of interests: Dr. Zhu reports grants from National Institutes of Health, American Lung Association, and Harvard University during the conduct of the study.
Conflict of interests: Drs. Mansbach, Camargo, and Hasegawa report grants from National Institutes of Health during the conduct of the study.
Conflict of interests: All other authors have indicated that they have no financial relationships relevant to this article to disclose.
- Received June 11, 2024.
- Accepted September 8, 2024.
- Copyright ©The authors 2024. For reproduction rights and permissions contact permissions{at}ersnet.org
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