Influence of single nucleotide polymorphisms in post-bronchiolitis wheezing

Abstract

INTRODUCTION: a large number of infants present post-bronchiolitis wheezing. It is not clear if genetics factors contribute to it.

AIMS: To evaluate the influence of Single Nucleotide Polymorphisms (SNP) in long-term outcomes of patients hospitalized for bronchiolitis.

METHODS: All patients hospitalized for bronchiolitis in two winter seasons in 3 tertiary pediatric hospitals were evaluated for epidemiological variables, underwent nasopharyngeal aspirate for detection of virus by PCR technique and blood collection to identify presence of SNPs. Polymorphisms were screened by AccuFill™ System for the OpenArray® Real-Time PCR Platform. Studied SNPs (gene) were: rs4986790 (TLR4), rs4986791 (TLR4), rs1927911 (TLR4), rs898830 (TLR2), rs7656411 (TLR2), rs352162 (TLR9), rs187084 (TLR9), rs1065341 (CCL5), rs2107538 (CCL5), rs2280788 (CCL5), rs2280789 (CCL5), rs10757212 (IFNA5), rs1060826 (NOS2), rs11688 (JUN), rs10735810 (VDR) and rs2228570 (VDR). All patients were followed-up for one year.

RESULTS: 85 patients (all < 1 year) were followed-up. Outcomes after 3 and 12 months of discharge (in percentage) were: wheezing (58.8 and 46.1), use of bronchodilators (56.0 and 47.4), use of oral steroids (38.8 and 43.4), need to seek the emergency room (38.1 and 35.1), need of hospitalization (8.3 and 6.4), pneumonia (10.6 and 3.8). 36.5% and 11.8% of patients used inhaled steroids and montelukast, respectively. SNPs associated with worse outcome were: rs1927911 (TLR4), rs7656411 (TLR2), rs352162 (TLR9), rs187084 (TLR9), rs1060826 (NOS2), rs2280789 (CCL5), rs2228570 (VDR) (p<0,05).

CONCLUSIONS: SNPs are associated with worse long-term outcome and maintenance of symptoms in patients hospitalized for bronchiolitis.