Genetic polymorphisms of the TNF-α-308G/A are associated with metabolic syndrome in asthmatic patients from Hebei province, China.

Asthma is a complex inflammatory disease involving the critical actions of several important cytokines. Epidemiological data show that obesity could increase the risk of asthma, and insulin resistance, or metabolic syndrome are an important risk factor for obesity asthma. Some studies identified that upstream of the transcription start site within the TNF-α gene promoter region-308 polymorphism was associated insulin resistance or metabolic disorders, while this site was closely related to asthma. But no research was performed to evaluate the influence of TNF-α-308G/A polymorphism on metabolic syndrome in asthmatic patients. Here, we recruited 248 asthmatic patients, who were separated into asthma with Mets/asthma without Mets groups and 226 matched healthy controls from Hebei Province to evaluate the influence of TNF-α-308G/A polymorphism on metabolic syndrome in asthmatic patients. Single nucleotide polymorphism of TNF-α-308 locus was genotyped using PCR-RFLP. Some biochemical variables were also determined. Our result showed that the genotypic and allelic frequency of rs1800629 did not show significant difference between asthmatic patients and normal controls. However, the frequency of A allele was significantly higher in asthma group with Mets (22.36%) than in controls (15.71%) (P = 0.02; OR = 0.647; 95% CI = 0.447-0.936). After analyzing the relationship between biochemical features of patients and genotype of TNF-α-308G/A, we found levels of LDL cholesterol, TNF-α and insulin, and HOMA-IR were significantly higher in the asthmatic patients carrying the GA and AA genotypes than in the carriers of GG genotype of rs1800629 (P = 0.029, P = 0.022, P = 0.043, respectively). Thus, our data suggested that TNF-α-308G/A variation was related to metabolic phenotype in asthma patients. Furthermore, we first identified TNF-α-308 A allele was the risk factor for asthmatic patients with Mets in Hebei population, China.