Abstract

Respiratory syncytial virus (RSV) is the leading cause of respiratory tract infection in infants. In this study we evaluated if single nucleotide polymorphism (SNPs) associated to the level of expression of interferon lambda (IFN-λ/IL28B), rs12979860 (CT/TT/CC) and rs8099917 (TG/GG/TT), and the tumor necrosis Factor (TNF-α), rs1800629 (AA/AG/GG), link with the severity of RSV bronchiolitis in a pediatric population. For this, 629 infants with no comorbilities were prospectively enrolled between July 2014 and December 2016 at admission time to the Emergency room, ambulatory and pediatric section of the Hospital Clínico Universidad Católica or Hospital Doctor Sótero Del Río. Biological samples (buccal swabs) were categorized according to the severity of RSV induced bronchiolitis exhibited by the donor. Genomic DNA was extracted from samples and SNPs of IL28B (rs12379860/rs8099917) and TNF-α (rs1800629) were determined using TaqMan technology. Results show that non-severe bronchiolitis patients associated to a major proportion of eutocic delivery, less admission to intensive care unit, reduced mechanical ventilation, a diminished bacterial infection, shorter hospital and ICU length-of-stay and less days of supplemental oxygen requirement. An association between the homozygous status of the minor allele of IL28B SNP rs8099917 (GG) with lower clinical severity (Odd Ratio: 0.13; P= 0.038) was evidenced, while the major allele (GT/TT) linked to severe cases. No association was observed between TNF-α rs1800629 or IL28B rs12379860 and the severity of RSV induced bronchiolitis. Based on these findings we conclude that IL28B SNP rs8099917, but not IL28B rs12379860 or TNF-α rs1800629, links with the clinical severity of RSV bronchiolitis