[Association between interleukin-8 gene-251 locus polymorphism and respiratory syncytial virus bronchiolitis and post-bronchiolitis wheezing in infants].
OBJECTIVE
Respiratory syncytial virus (RSV) infects nearly all children under two years of age. It is not understood why some develop serious bronchiolitis. Whether there is a genetic component is not known. The nature of the association between RSV bronchiolitis and subsequent wheezing remains unknown. interleukin-8 (IL-8) is a potent neutrophil chemokine and activator, which plays a role in virus-induced wheezing diseases. The purpose of this study was to assess the genetic association between the IL-8 gene promoter -251A/T polymorphism and RSV bronchiolitis and post-bronchiolitis wheezing in children.


METHODS
Totally 320 children who were hospitalized for bronchiolitis together with positive immunofluorescence for RSV were recruited in this study from Jan. 2002 to Jan. 2004. A group of 272 healthy children were enrolled as controls. The age of these children ranged from 1 to 12 months. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to identify the polymorphism at position-251 of the IL-8 promoter in RSV bronchiolitis and control groups. The total IL-8 and IgE concentrations in serum samples were measured by enzyme-linked immunosorbent assay (ELISA). The patients with RSV bronchiolitis were followed up in order to analyze the occurrence of wheezing post-bronchiolitis.


RESULTS
(1) Both A allele and T allele were detected at -251 of the IL-8 promoter; the prevalence of the A allele in RSV bronchiolitis group was 45.6%, as compared with 37.7% in normal group. The prevalence of IL-8-251A allele was significantly different between the two groups (P < 0.05). (2) For genotypes T/T, A/T, A/A in RSV bronchiolitis, level of serum IL-8 were (17 +/- 6) ng/L, (21 +/- 7) ng/L, (24 +/- 9) ng/L, respectively, the difference was significant among the three genotypes (P < 0.01). (3) The prevalence of the A allele in the group who wheezed after the episode of RSV bronchiolitis was 54.6%, as compared with 35.8% in the group who had bronchiolitis but did not go on to wheeze. The prevalence of IL-8-251A allele was significantly different between the two groups (P < 0.05).


CONCLUSIONS
Polymorphism of IL-8 promoter-251A/T was associated with susceptibility to RSV bronchiolitis in children. The association of IL-8-251A with severe RSV bronchiolitis is most marked in the children who go on to wheeze.
Tian
Man
M
Department of Respiratory Medicine, The Affiliated Nanjing Children's Hospital of Nanjing Medical University, Nanjing 210008, China.
Zhao
De-yu
DY
Wen
Guan-yu
GY
Shi
Sheng-yun
SY
Chen
Rong-hua
RH
D000293:Adolescent; D000483:Alleles; D001988:Bronchiolitis / Q000150:complications*; D002648:Child; D002675:Child, Preschool; D002874:Chromosome Mapping; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007223:Infant; D016209:Interleukin-8 / Q000235:genetics*; D008297:Male; D011110:Polymorphism, Genetic; D012135:Respiratory Sounds / Q000209:etiology / Q000235:genetics*; D018357:Respiratory Syncytial Virus Infections / Q000150:complications* / Q000821:virology
D016209:Interleukin-8