Variations in association of Interleukin 6 -G174C single nucleotide polymorphism with type 2 diabetes mellitus—a review

Genetic Variation of a −176g>c Interleukin-6 Correlated with White Blood Cells Count in Obesity of Indonesia

BACKGROUND: Obesity is a risk factor for cardiovascular disease. Obesity can trigger inflammation by increasing the synthesis of interleukin-6 (IL-6) which leads to leukocyte recruitment, differentiation of B lymphocytes, activating T lymphocyte cells, and triggering hematopoiesis. Variations in the IL-6 promoter gene are known to affect transcription rates. The previous studies have still found different results regarding the relationship between these gene variations and blood cell numbers. AIM: This study aimed to determine the influence of IL-6 gene variation with white blood cells counts in obese people of Indonesia. METHODS: A total of 148 people participated in this cross-sectional study. The number of obese people was 80 subjects and there were 68 non-obese people as controls. Obesity was determined based on the criteria of Asians. RESULTS: Genotype CC was not found in this study, while the GC genotype was found only in the obese group. The GG genotype in obese group had waist circumference, diastolic blood pressure, and higher lymphocyte rates significantly higher than the non-obese group (p < 0.05). CONCLUSIONS: Variation of −174G>C IL-6 gene is associated with high white blood cell counts, especially lymphocytes number in obese people in Indonesia.

IL-6 and IL-18 cytokine gene variants of pulmonary tuberculosis patients with co-morbid diabetes mellitus and their household contacts in Hyderabad

PURPOSE

Association of cytokine genes reflects their susceptibility towards infection and disease in household contacts (HHC) of pulmonary tuberculosis (PTB) patients. Hyperglycemia, a common factor in diabetics might influence their risk towards mycobacterium tuberculosis infection and disease development. This study determines the association of IL-6 and IL-18 cytokine gene variants of TB patients with diabetes mellitus (TBDM) and their HHC in Hyderabad.

METHODS

Single nucleotide polymorphisms of IL-6 (-174 G>C and -572 G>C) and IL-18 (-137 G>C and -607 C>A) cytokine genes were genotyped by Amplification Refractory Mutation System and Restriction Fragment Length polymerase chain reaction in total of 705 subjects comprising of TBDM, their HHC, PTB, DM and Healthy controls (HC).

RESULTS

At IL-6 -174G>C variant, GG genotype, G allele in TBDM and TBDM HHC, at -572G>C variant, C allele in TBDM and GG haplotype in TBDM HHC were showing positive association, however DM have not shown any association at IL-6 polymorphic sites. With respect to the IL-18 gene polymorphisms, at -137 G>C variant, GG genotype was positively associated in PTB while at -607 C>A variant positive association was shown with AC genotype in TBDM, their HHC and DM; GACC diplotype in TBDM and GCGC in PTB.

CONCLUSION

Our findings suggest that susceptible combination of IL-6 and IL-18 cytokine genes associated with disease in the HHCs highlight their risk of inclination towards the disease.