Cytokine promoter polymorphisms in Taiwanese patients with Graves' disease

OBJECTIVES: This study aimed to examine the association between promoter polymorphisms of Th1 and Th2 cytokine genes [interleukin-4 (IL-4 T-34C, A-81G, C-285T and T-589C), IL-6 (G-174C), IL-10 (A-592C and T-819C) and tumour necrosis factor-alpha (TNF-alpha G-238A and G-308A)] and Graves' disease (GD) in Taiwanese population. DESIGN AND METHODS: Genomic DNA was extracted from peripheral blood cells of 137 GD patients and 189 control subjects. Cytokine gene polymorphisms were analyzed by polymerase chain reaction and restriction fragment length polymorphism. RESULTS: Genotype frequencies of TNF-alpha G-238A or G-308A between control and GD subjects were significantly different. Frequencies of the high TNF-alpha secreting alleles (-238*A and -308*A) and IL-10 -819*C allele were significantly increased in GD patients. No significant differences regarding IL-4 or IL-6 gene polymorphisms between GD patients and control subjects were found. CONCLUSIONS: Our data demonstrated that TNF-alpha G-238A and G-308A genotypes were strongly associated with GD incidence.