Background
Recently, single nucleotide polymorphisms were proposed as potentially new predictors for perioperative risks, such as myocardial infarction and organ dysfunction. The objectives of this study were to investigate whether IL-6 -572C/G, IL-10 -1082A/G, and TNF-alpha -308G/A were associated with acute lung injury after cardiac surgery with cardiopulmonary bypass.
Material and Method
One hundred patients with acute lung injury at 24 hours after cardiac surgery with cardiopulmonary bypass and 112 patients without acute lung injury as controls were included. Genotyping assay was performed with real-time fluorescence-based allele-specific PCR. Serum levels of IL-6, IL-10, and TNF-alpha were also determined by ELISA. Associations between these polymorphisms and acute lung injury, as well as serum cytokine levels, were analyzed. All patients were genotyped for IL-6 -572C/G, IL-10 -1082A/G, and TNF-alpha -308G/A. Circulating level of these cytokines were also determined.
Results
Acute lung injury after cardiac surgery with cardiopulmonary bypass was associated with IL-6 -572C/G polymorphism, but not IL-10 -1082A/G or TNF-alpha -308G/A. This functional polymorphism was further confirmed by multivariate analyses. The ratio of circulating concentrations of IL-10/IL-6 was associated with IL-6 genotypes and incidence of acute lung injury as well.
Conclusions
The IL-6 -572 polymorphism was associated with acute lung injury after cardiac surgery with cardiopulmonary bypass. Proinflammatory and anti-inflammatory imbalance might be the clinical significance of IL-6 polymorphism (ClinicalTrials.gov number, NCT00826072).

Keywords: Polymorphism, Single Nucleotide, Interleukin-6 - genetics, Interleukin-10 - genetics, Inflammation - genetics, Enzyme-Linked Immunosorbent Assay, DNA Primers, Cytokines - genetics, Cardiopulmonary Bypass - adverse effects, Base Sequence, Acute Lung Injury - genetics, Tumor Necrosis Factor-alpha - genetics