Association of TNF-alpha, TNF-beta, IFN-gamma and IL-1Ra gene polymorphisms with Graves' disease in the Thai population.

Cytokines play a key role in the regulation of immune and inflammatory responses. Therefore, cytokine genes are potentially related to susceptibility to Graves' disease (GD). The aim of this study was to investigate the putative functional polymorphisms within tumor necrosis factor-alpha (TNF-alpha), tumor necrosis factor-beta (TNF-beta), interferon-gamma (IFN-gamma), and interleukin-1 receptor antagonist (IL-1Ra) genes, in patients with GD (n = 137) compared to a healthy Thai control group (n = 137). The results showed no statistically significant difference between the study groups for TNF-beta (Ncol site in intron 1), IFN-gamma (+874 in intron 1), and IL-1Ra (variable numbers of tandem repeats in intron 2) gene polymorphisms. Only the -863A allele within the promoter region of the TNF-alpha gene, which may affect the affinity of the promoter nuclear factor (NF)-kappab interaction, was found to be increased in GD patients compared to the controls (p = 0.009, OR = 1.8, 95% CI = 1.15 to 2.84). The effect of the -863A allele of the TNF-alpha gene was similar to the autosomal dominance mode of inheritance (p = 0.01, OR = 2, 95% CI = 1.16 to 3.44). This polymorphism may be involved in the susceptibility to GD in part through its higher promoter activity of TNF-alpha production.