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.