Interleukin-6 Polymorphism is Associated with Chorioamnionitis and Neonatal Infections in Preterm Infants

Objectives

To evaluate whether genotypes of interleukin (IL)-6 gene promoter positions -174 and -572 are associated with histologic chorioamnionitis and neonatal inflammatory disease in preterm infants.

Study design

DNA from very low birth weight or very preterm infants (n = 107) was genotyped for IL-6-174 and -572 polymorphisms (GG/GC/CC). The placentas were analyzed for histological inflammatory findings. Data on neonatal inflammatory diseases, including chronic lung disease (CLD), necrotizing enterocolitis (NEC), and septicemia, were collected using the definitions of the Vermont Oxford Network database.

Results

In univariate analyses, the IL-6-174 GG genotype was associated with a higher incidence of histologic chorioamnionitis. In multivariate analyses, the -174 GG and -572 GC genotypes were correlated with histologic chorioamnionitis (P = .039 and .009, respectively). Gestational age was not associated with genotype polymorphisms. IL-6-174 genotypes were not associated with CLD and/or NEC, but the CC genotype was correlated with septicemia in both univariate and multivariate analyses (P = .027). IL-6-572 genotypes were not associated with neonatal inflammatory disease.

Conclusions

The IL-6-174 GG and -572 GC genotypes were associated with a higher incidence of histologic chorioamnionitis, and the IL-6-174 CC genotype was associated with septicemia in preterm infants. These findings suggest that the genetic composition of the IL-6 promoter area plays a significant role in the pathogenesis of chorioamnionitis and neonatal infections.

Abbreviations: CI, Confidence interval, CLD, Chronic lung disease, IL, Interleukin, LPS, Lipopolysaccharide, NEC, Necrotizing enterocolitis, OR, Odds ratio, PCR, Polymerase chain reaction, TNF, Tumor necrosis factor, VLBW, Very low birth weight