Maternal interleukin-6 (-174) C/C polymorphism is associated with chorioamnionitis and cystic periventricular leucomalacia of the preterm infant.
OBJECTIVE
To evaluate the association between maternal interleukin (IL)-6 G(-174)C polymorphism and cystic periventricular leukomalacia (cPVL) of the preterm newborn.


METHODS
After searching a local database, we recruited 132 preterm infants with diagnosis of cPVL, 44 Caucasian mothers were also recruited to participate in this candidate gene-association study at a single teritary care center. Data related to maternal IL-6 G(-174)C polymorphisms were compared with 41 controls, and furthermore compared with data from umbilical cord blood samples from a consecutive birth cohort of 395 healthy newborns, and published data from Caucasian populations including 1104 adults, respectively. In addition, subgroup analysis was performed in cases with either history of preterm premature rupture of the membranes (PPROM) or clinical chorioamnionitis (CCA). IL-6 genotyping was performed using an allele-specific polymerase chain reaction technique.


RESULTS
Frequencies of the IL-6 G(-174)C polymorphisms did not differ between cases (GG, 29.5%; GC, 54.5% and CC, 15.9%) and controls (GG, 34.2; GC, 51.2 and CC, 14.6%). Subgroup analysis of 31 cases with history of PPROM (GG, 25.8; GC, 54.8 and CC 19.4%) and controls did not reveal significant differences, but a significantly higher frequency of the CC genotype was found in 23 cases with a history of CCA (34.8%) compared with controls by either univariate (P=0.032; odds ratio 3.11, 95% confidence interval (CI) 1.11 to 8.68) or multivariate analysis (P=0.049, odds ratio 2.54, 95% CI 1.01 to 6.45). These data were confirmed by a comparing the CC genotype frequency to 395 term controls (CC 14.7%, P=0.005) and to the mean CC genotype frequency of 1104 Caucasian adults (CC 15.6%, P<0.0001).


CONCLUSIONS
Frequencies of the IL-6 G(-174)C polymorphisms did not differ between groups. Subgroup analysis revealed an association of the CC genotype with CCA and cPVL in the preterm newborn.
Research Unit for Neonatal Infectious Diseases and Epidemiology, Division of Neonatology, Department of Pediatrics, Medical University of Graz, Graz, Austria. bernhard.resch@medunigraz.at
B
B
Resch
A
A
Radinger
C
C
Mannhalter
B
B
Horvath
A
A
Binder
W
W
Zenz
W
W
Walcher
J
J
Haas
W D
WD
Müller
B
B
Pertl
D000328:Adult; D001317:Austria; D002821:Chorioamnionitis / Q000097:blood / Q000235:genetics*; D005260:Female; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease / Q000196:embryology; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood; D015850:Interleukin-6 / Q000097:blood / Q000235:genetics*; D007969:Leukomalacia, Periventricular / Q000235:genetics*; D011110:Polymorphism, Genetic; D011247:Pregnancy; D055815:Young Adult
D015850:Interleukin-6