Distinct Molecular Subtypes of RSV Bronchiolitis Identified

MONDAY, June 21, 2021 (HealthDay News) — Distinct molecular subtypes of respiratory syncytial virus (RSV) bronchiolitis have been identified and are associated with differing levels of asthma risk, according to a study published online June 14 in Nature Communications.

Yoshihiko Raita, M.D., M.P.H., from Massachusetts General Hospital in Boston, and colleagues integrated clinical, virus, airway microbiome (species-level), transcriptome, and metabolome data of 221 infants hospitalized with RSV bronchiolitis in a prospective cohort study to examine biologically distinct endotypes.

The researchers identified four biologically and clinically meaningful endotypes: clinical^classicmicrobiome^{M. nonliquefaciens}inflammation^{IFN-intermediate} (A); clinical^atopicmicrobiome^{S. pneumoniae/M. catarrhalis}inflammation^IFN-high (B); clinical^severemicrobiome^mixedinflammation^IFN-low (C); and clinical^non-atopicmicrobiome^{M. catarrhalis}inflammation^IL-6 (D). Endotype B infants, who are characterized by a high proportion of immunoglobulin E sensitization and rhinovirus coinfection, S. pneumoniae/M. catarrhalis codominance, and high IFN-α and -γ response, had a significantly higher risk for developing asthma compared with endotype A infants (38 versus 9 percent; odds ratio, 6.00).

“Our data add significant support to the emerging concept that bronchiolitis represents several diseases with unique biological mechanisms,” Raita said in a statement. “For clinicians, our findings give an evidence base for the early identification of high-risk children during an important period of airway development: early infancy. For researchers, our data offer new avenues for the development of subgroup-specific strategies — such as fine-tuning the airway immune response and microbiome — for treating bronchiolitis and preventing asthma.”

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