Clinical immunology
The influence of IL-6 and TNF-α genes promoter region polymorphisms (G174C – IL-6 and G308A – TNF-α) on the level of cytokines in obese and normal weight subjects

Proinflammatory cytokines level, including IL-6 and TNF-α, is changing significantly during hyperplasia and hypertrophy of adipocytes. The increase in IL-6 and TNF-α concentration is a direct result of increased expression of their genes. Gene polymorphisms, especially those localized in transcription regulating regions such as promoters, are among factors influencing gene expression profile. The aim of the study is to assess the influence of polymorphic changes in promoter regions: G174C in IL-6 gene and G308A in TNF-α gene on the level of the cytokines in obese and normal weight subjects. The study included 102 obese subjects and 77 normal weight subjects. Genotyping was performed using PCR-RFLP technique, while cytokine level was assessed using ELISA assay. The obtained results showed the connection between a certain genotype and IL-6 and TNF-α genes expression level. In non obese subjects with C/C genotype IL-6 level was lower than in subjects with G/C genotypes. In contrary in TNF-α gene the difference was found in the group of obese. The A allel carriers were characterized by higher TNF concentration. However, many additional modifying factors, which often conceal the influence of polymorphisms on gene expression, should be considered.