Objective: To study the association of tumor necrosis factor (TNF)-alpha-308G/A and interleukin (IL)-6-174G/C gene polymorphisms with the susceptibility of respiratory syncytial virus (RSV) bronchiolitis.
Methods: Polymerase chain reaction-restriction fragment length polymorphism ( PCR-RFLP) was used to identify the polymorphisms at position 308 of the TNF-alpha promoter and -174 of the IL-6 promoter in 150 children with RSV bronchiolitis and 120 healthy children (control group).
Results: The frequency of GG, GA and AA genotypes of TNF-alpha-308 was 68.0%, 28.0% and 4.0% respectively in the RSV group, while that was 80.8%, 19.2% and 0 respectively in the control group. There were significant differences in the genotype frequencies between the two groups (chi2=5.665, p<0.05). The frequency of G and A alleles in the RSV group was 82.0% and 18.0% respectively, while that was 90.4% and 9.6% respectively in the control group. The frequency of A allele in the RSV group was significantly higher than that in the control group (chi2=7.726, p<0.05). Compared to the children carrying G allele, the children with A allele demonstrated a 2.071-fold increased risk of RSV bronchiolitis (OR=2.071, p<0.05). Only GG genotype was detected at position -174 of IL-6 in both groups.
Conclusions: TNF-alpha-308A is associated with the susceptibility of RSV bronchiolitis and it might be an important candidate gene for the development of RSV bronchiolits. IL-6-174G/C gene polymorphism is not found in children in Wenzhou area.