title: Interleukin-6 polymorphism and bronchopulmonary dysplasia risk in very low-birthweight infants.
abstract: BACKGROUND
  The aim of the present study was to evaluate the role of interleukin (IL)-6-634 polymorphism in neonatal disorders such as bronchopulmonary dysplasia (BPD) and periventricular leukomalacia (PVL) in very low-birthweight (VLBW) infants.
  
  
  METHODS
  This prospective cohort study included 202 infants (gestational age at birth, 23-34 weeks; birthweight, 500-1499 g). Genotypic analysis (polymerase chain reaction-restriction fragment length polymorphism) was performed with DNA extracted from whole-blood samples.
  
  
  RESULTS
  Genotype distribution (66.8% CC, 28.2% CG, 5.0% GG) was similar to that in the adult Japanese population. BPD occurred in 85 infants (42.1%) among 202 VLBW infants. The duration of O(2) therapy in infants with CG/GG genotypes was significantly longer than that in infants with the CC genotype (CG/GG vs CC: 40.3 ± 52.2 days vs 28.4 ± 32.6 days, P < 0.05), but the prevalence of BPD was not associated with the CG/GG genotype (CG/GG, 40.0%; CC, 46.3%, P= 0.24). Infants with CG/GG genotypes were more likely to have received postnatal corticosteroid therapy for BPD than those with the CC genotype (CG/GG vs CC: 20.9% vs 11.1%, P = 0.05). PVL occurred in six infants (3.0%). There was no significant difference in the prevalence of PVL among IL-6-634 polymorphisms (CG/GG, 3.0%; CC, 3.0%, P = 0.65).
  
  
  CONCLUSIONS
  IL-6-634 polymorphism is associated with duration of oxygen therapy in VLBW infants. This suggests that the IL-6-634 polymorphism G allele is an aggravating factor of BPD. IL-6-634 polymorphism is not associated with PVL.
authors.affiliation: Division of Pediatrics, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan. touheiusu@med.niigata-u.ac.jp
authors.forename: Touhei
authors.initials: T
authors.lastname: Usuda
authors.forename: Takehiro
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Seiichi
authors.initials: S
authors.lastname: Sakakibara
authors.forename: Akira
authors.initials: A
authors.lastname: Kobayashi
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kaneko
authors.forename: Masaki
authors.initials: M
authors.lastname: Wada
authors.forename: Junya
authors.initials: J
authors.lastname: Onozuka
authors.forename: Osamu
authors.initials: O
authors.lastname: Numata
authors.forename: Katsumi
authors.initials: K
authors.lastname: Torigoe
authors.forename: Hajime
authors.initials: H
authors.lastname: Yamazaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Sato
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Nagayama
authors.forename: Makoto
authors.initials: M
authors.lastname: Uchiyama
mesh_terms: D001997:Bronchopulmonary Dysplasia / Q000235:genetics*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight; D015850:Interleukin-6 / Q000235:genetics*; D007969:Leukomalacia, Periventricular / Q000235:genetics*; D008297:Male; D020641:Polymorphism, Single Nucleotide; D011446:Prospective Studies
chemical_list: D015850:Interleukin-6