Objective: Interleukin-6 (IL-6) is an immunoregulative proinflammatory cytokine with pleiotropic functions. It was reported that plasma level of IL-6 in type 1 diabetes mellitus (T1DM) patients was higher than in healthy individuals. IL-6 is supposed to take part in pancreatic beta-cells destruction. So, we considered IL-6 gene to be a candidate one for T1DM. The aim of present study was to investigate the role of IL-6 gene promoter polymorphism in T1DM development.
Methods: We studied 115 Russian and 125 Tatar T1DM patients (mean-aged 32.02±13.56). Control group consisted of 253 Russian and 239 Tatar unrelated age-matched healthy subjects. Diagnosis was established according to the World Health Organization criteria (1999). DNA was extracted from whole venous blood using phenol-chlorophorm method. Genotyping was carried out by polymerase chain reaction followed by MbiI digestion. Statistical analysis was performed using Fishers exact test, P-value of ≤0.05 was taken as statistically significant.
Results: We have found that IL-6 572 GG genotype and G allele were associated with increased risk of T1DM both in Russians (OR=1.72, P=0.050, CI=1.002.96 and OR=1.68, P=0.045, CI=1.012.79, respectively) and in Tatars(OR=1.67, P=0.036, CI=1.032.70 and OR=2.04, P=0.002, CI=1.283.26, respectively).
Conclusion: Our results provide the evidence that IL-6 −572 G/C polymorphism is associated with T1DM in Tatars and Russians from Bashkortostan (Russia).