Abstract
INTRODUCTION: Acute viral bronchiolitis is the main lower airway infection and the leading cause of hospitalization in infants in developed countries. Most infants hospitalized for bronchiolitis do not present risk factors for this disease.
METHODS: We prospectively evaluated 181 severe bronchiolitis patients admitted in 3 hospitals over a 2-year period (2013-2014) who required oxygen therapy. Control group consisted of 536 healthy adults. Patients were evaluated for epidemiological variables, underwent nasopharyngeal aspiration for the detection of 15 viruses by multiplex-PCR and blood collection for the identification of 16 single-nucleotide polymorphisms (SNPs) in genes involved in the immune response. Outcomes assessed were length of stay, length of oxygen use, need and length of intensive care unit stay (ICU), need and length of mechanical ventilation and progression to death.
RESULTS: We observed an association between rs2107538(RANTES) and bronchiolitis caused by Respiratory Synsytial Virus (RSV) and by RSV-A, and between rs1060826(NOS2) and bronchiolitis caused by Rhinovirus. SNPs rs4986790(TLR4), rs898830(TLR2) and rs2228570(VDR) were associated with progression to death. SNP rs7656411(TLR2) was associated with length of oxygen use. SNPs rs352162(TLR9), rs187084(TLR9) and rs2280788(RANTES) were associated with need of ICU admission. SNPs rs1927911(TLR4), rs352162(TLR9) and rs2107538(RANTES) were associated with need of mechanical ventilation. Patients with RSV-B had shorter length of stay and oxygen use.
CONCLUSION: Genetic variability in immune response genes appears to determine the outcomes of severe bronchiolitis, while the genetic contribuition to the prevalence of severe bronchiolitis is condicioned by the type of virus.
- Copyright ©the authors 2016
