Interleukin-6 and tumor necrosis factor-alpha gene polymorphisms in chronic idiopathic urticaria.

BACKGROUND This study was performed to evaluate association of gene polymorphisms among proinflammatory cytokines and susceptibility to chronic idiopathic urticaria (CIU). METHODS Ninety patients with prolonged urticaria more than 6 weeks were included as case group. Single nucleotide polymorphisms (SNPs) of IL-6 (G/C -174, G/A nt565) and TNF-α (G/A -308, G/A -238) were evaluated, using polymerase chain reaction (PCR); and the results were compared to the control group. RESULTS G allele was significantly higher in the patients at locus of -238 of promoter of TNF-α gene (p<0.001). Frequency of following genotypes were significantly lower in patients with CIU, compared to controls: AG at -308 and GA at -238 of TNF-α gene (p<0.05 and p<0.001, respectively), CG at -174 and GG at +565 of IL-6 gene (p<0.05). Additionally, following genotypes were more common among patients with CIU: GG at -308 and -238 of TNF-α gene (p<0.05 and p<0.001, respectively), GG at -174 and GA at +565 of IL-6 gene (p<0.05). CONCLUSIONS Pro-inflammatory cytokine gene polymorphisms can affect susceptibility to CIU. TNF-α promoter polymorphisms as well as IL-6 gene polymorphisms are associated with CIU.