The relationship between nasopharyngeal CCL5 and microbiota on disease severity among infants with bronchiolitis

Area of Science:

• Pediatric Respiratory Medicine
• Microbiology
• Immunology

Background:

• Viral bronchiolitis is a common respiratory infection in infants.
• The airway microbiota and chemokine ligand 5 (CCL5) are implicated in disease severity.
• The interaction between airway microbiota and CCL5 in bronchiolitis is not well understood.

Purpose of the Study:

• To investigate the combined role of nasopharyngeal airway microbiota profiles and CCL5 levels in predicting bronchiolitis severity.
• To determine if interactions exist between microbiota and CCL5 in relation to intensive care unit (ICU) admission and hospital length-of-stay (LOS).

Main Methods:

• Multicenter prospective cohort study of 1005 infants under one year old hospitalized for bronchiolitis.
• Nasopharyngeal samples analyzed for microbiota composition.
• CCL5 levels measured in nasopharyngeal aspirates.
• Statistical analysis to assess interactions between microbiota profiles and CCL5 levels for ICU use and LOS ≥3 days.

Main Results:

• A significant interaction was observed between airway CCL5 levels and microbiota profiles for ICU use (P_interaction =.02) and LOS ≥3 days (P_interaction =.03).
• In infants with low CCL5, a Haemophilus-dominant microbiota was associated with significantly higher odds of ICU use (OR, 3.20) and LOS ≥3 days (OR, 4.14) compared to a Moraxella-dominant profile.
• No significant associations were found between microbiota profiles and severity outcomes in infants with high CCL5 levels.

Conclusions:

• Nasopharyngeal microbiota composition and CCL5 levels interact to influence bronchiolitis severity in infants.
• Lower CCL5 levels may exacerbate the risk associated with specific airway microbiota profiles, leading to more severe clinical outcomes.
• These findings highlight potential therapeutic targets for managing severe bronchiolitis by considering both microbial and host inflammatory factors.