Is interleukin-6 -174 genotype associated with the development of septicemia in preterm infants?
OBJECTIVE
Systemic infection affects one quarter of preterm infants. Defense from infection is in part mediated by the cytokine interleukin-6 (IL-6). We tested the hypothesis that the IL-6 -174 GG genotype, associated with lower IL-6 response to inflammation, is also associated with the development of septicemia in preterm infants.


METHODS
The study group comprised 157 infants who were born at < or =32 weeks. Genotype distribution (34% [54] GG, 46% [72] GC, 20% [31] CC) and C allele frequency (0.43; 95% confidence interval [CI]: 0.37-0.48) were similar to the UK adult population. Among the patients who developed bacterially confirmed septicemia (n = 51 [33%]), there was a significantly higher prevalence of the IL-6 -174 GG genotype than that observed in those who did not develop infection (47% vs 28% for GG: odds ratio [OR]: 2.3; 95% CI: 1.1-4.5). This association remained statistically significant (OR: 2.7; 95% CI: 1.2-6.3) after multiple binary logistic regression adjustment for other significant predictors of the development of septicemia. Late infection alone was similarly associated with GG genotype (septicemia 47% vs no septicemia 29% for GG: OR: 2.2; 95% CI: 1.1-4.3).


CONCLUSIONS
Variation in the IL-6 gene seems to influence the defense against bacterial pathogens in the very preterm infant.
Harding
David
D
Department of Child Health, University of Bristol, Bristol, United Kingdom. david.harding@bristol.ac.uk
Dhamrait
Sukhbir
S
Millar
Ann
A
Humphries
Steve
S
Marlow
Neil
N
Whitelaw
Andrew
A
Montgomery
Hugh
H
D000483:Alleles; D019943:Amino Acid Substitution; D015331:Cohort Studies; D004200:Diseases in Twins / Q000453:epidemiology; D004739:England / Q000453:epidemiology; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D015850:Interleukin-6 / Q000235:genetics / Q000502:physiology*; D008297:Male; D020125:Mutation, Missense; D017354:Point Mutation; D011446:Prospective Studies; D018805:Sepsis / Q000453:epidemiology / Q000235:genetics*; D016037:Single-Blind Method
D015850:Interleukin-6