Interferon lambda 1-3 expression in infants hospitalized for RSV or HRV associated bronchiolitis

Area of Science:

• Immunology
• Virology
• Pediatric Respiratory Illnesses

Background:

• Type III interferons (IFNs) play a crucial role in antiviral immunity.
• Infant bronchiolitis, commonly caused by RSV and HRV, is a significant respiratory illness.
• Understanding the differential IFN responses to these viruses is key to managing disease severity.

Purpose of the Study:

• To evaluate airway expression of type III IFNs (IFN lambda 1-3) in infants hospitalized with RSV or HRV bronchiolitis.
• To determine if IFN lambda expression differs based on the specific virus (RSV vs. HRV).
• To investigate the association between IFN lambda levels, clinical severity, and established IFN-stimulated genes (ISGs) like MxA and ISG56.

Main Methods:

• Analysis of nasopharyngeal washes from 118 infants diagnosed with RSV or HRV bronchiolitis.
• Virological studies to identify the causative virus.
• Molecular analysis to quantify type III IFN responses and ISG mRNA levels (MxA, ISG56).

Main Results:

• Respiratory syncytial virus (RSV) infection elicited significantly higher levels of IFN lambda subtypes compared to human rhinovirus (HRV) infection.
• IFN lambda 1 and IFN lambda 2-3 levels were positively correlated with each other and with MxA and ISG56 mRNA.
• Higher IFN lambda 1 levels were associated with increased clinical severity scores and elevated respiratory rate in RSV-infected infants.

Conclusions:

• Distinct patterns of type III IFN lambda expression exist between RSV and HRV infections in infants.
• IFN lambda 1 expression is a potential biomarker for the severity of RSV-induced bronchiolitis.