Association of polymorphisms in IL6 gene promoter region with type 1 diabetes and increased albumin-to-creatinine ratio.

Background: Pro-inflammatory cytokines, such as interleukin-6 (IL-6), have been considered as key factors in type 1 diabetes mellitus (T1DM) and diabetic nephropathy, thus, our aim was to investigate the association of IL6-174G>C (rs1800795) and -634C>G (rs1800796) polymorphisms with T1DM susceptibility and diabetic nephropathy.

Methods: These polymorphisms were analyzed in 144 children and adolescents with T1DM and 173 normoglycemic control subjects. Glycemic control, laboratory parameters of kidney function and serum lipids were evaluated. By studying only T1DM patients, we evaluated the polymorphisms associated with relevant biochemical parameters in various genetic models.

Results: Type 1 diabetes mellitus patients showed poor glycemic control and albumin-to-creatinine ratio, total cholesterol and LDL-cholesterol levels increased when compared with normoglycemic subjects (p < 0.001, p = 0.004 and p < 0.001, respectively). IL6-174C allele was associated with an increased risk of developing T1DM (OR = 1.53, CI = 1.01-2.31, p = 0.044). In the T1DM group, IL6-174CC carriers showed higher concentrations of glycated hemoglobin (p = 0.029), albumin-to-creatinine ratio (p = 0.021), total cholesterol (p = 0.010), and LDL-cholesterol (p = 0.002), when compared with GG+GC carriers. No association was found for the IL6-634C>G polymorphism.

Conclusions: These results suggest that IL6-174G>C may contribute to T1DM and increased albumin-to-creatinine ratio as well as to poor glycemic control and hyperlipidemia.