Association of toll-like receptor 4 polymorphisms with type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is characterized by a chronic low-grade inflammatory state. Toll-like receptor 4 (TLR4) is a critical mediator of innate immunity. Polymorphisms in TLR4 gene have been shown to be associated with impaired inflammatory response. Here, we investigated the association of TLR4 polymorphisms with T2DM. Four TLR4 polymorphisms (+986A/G, +1196C/T, +3725G/C, and +11367G/C) were genotyped in a total number of 822 T2DM patients and 835 healthy controls. Results showed that the +986A/G and +1196C/T polymorphisms did not exist in the Han Chinese population. The prevalence of TLR4 +3725GC and CC genotypes were significantly decreased in T2DM cases than in controls (odds ratio (OR) = 0.62, 95 % confidence interval (CI) = 0.50-0.78, p = 3.48 × 10(-5), and OR = 0.36, 95 % CI = 0.22-0.59, p = 1.55 × 10(-5), respectively). Also, the frequency of TLR4 +3725C allele was significantly lower in T2DM patients (p = 2.46 × 10(-9)). When analyzing the TLR4 +11367G/C polymorphism, the +11367CC genotype revealed lower numbers in patients compared to healthy controls (OR = 0.46, 95 % CI = 0.27-0.78, p = 0.0032). Analysis of the clinical features on the control subjects demonstrated no correlations between these TLR4 polymorphisms and sex, age, body mass index, etc. (p > 0.05). In conclusion, these data indicate that TLR4 +3725G/C and +11367G/C polymorphisms may be novel protective factors against T2DM in the Chinese population.