Single nucleotide polymorphisms in interleukin-6 and their association with venous thromboembolism

The aim of the present study was to reveal the contribution of single nucleotide polymorphisms of the interleukin-6 (IL-6) gene and the progression of venous thromboembolism (VTE). A case-control study composed of 246 VTE patients, including 160 from the Han population (76 males and 84 females, mean age 57.41 +/- 13.25 years), 86 from the Uyghur population (41 males and 45 females, mean age 51.61 +/- 13.73 years) and 292 gender and ethnicity-matched control participants, including 170 from the Han population (91 males and 79 females, mean age 55.82 +/- 11.83 years) and 122 from the Uyghur population (64 males and 58 females, mean age 53.52 +/- 13.64 years) were enrolled in the present study. The results demonstrated that the serum levels of IL-6, C-reactive protein (CRP), D-dimer, fibrinogen, plasminogen activator inhibitor-1 and leptin were significantly higher in the VTE group compared with the control group (P<0.05). The frequencies of the -572C/G promoter polymorphisms of the IL-6 genotypes CC, CG and GG were identified to be 34, 48 and 18% in the Han population and 33, 47 and 20% in the Uyghur population, respectively. The allele frequency distributions of the C and G alleles were 58 and 42% in the Han population and 56 and 43% in the Uyghur population, respectively. Significant differences were identified in the -572C/G promoter polymorphisms between the VTE group and the control group (P<0.05). For the -597G/A polymorphism, all individuals carried the GG and GA genotype; AA genotypes were not detected. Logistic regression analysis was used to identify the risk factors for VTE, adjusting by confounding factors, the results of which demonstrated that the CC homozygote of the IL-6 -572G/C, CRP, IL-6 and high-density lipoprotein-cholesterol were independent risk factors of VTE (P<0.05). In conclusion, the -572G/C genotype of IL-6 may be a genetic marker of VTE in the Han and Uyghur populations.