Single nucleotide polymorphisms of IL-2 , but not IL-12 and IFN - γ , are associated with increased susceptibility to chronic spontaneous urticaria

Background A clear picture of interaction of Th1/Th2 cytokines in pathogenesis of chronic spontaneous urticaria (CSU), remains elusive. Impaired IFN-γ production and decreased levels of IL-2 have been reported. The aim of this study was to evaluate the association of Th1 cytokines; IL-2, IL-12 and IFN-γ polymorphisms with CSU. Methods 90 patients with CSU and 140 age-sex matched subjects were included in this study. DNA samples were evaluated through PCR-SSP assay in order to detect single nucleotide polymorphisms of IL-12 (A/C −1188) or (rs3212227), IFN-γ (A/T UTR5644) or (rs2069717) and IL-2 (G/T −330 and G/T +166) or (rs2069762 and rs2069763). Results G allele at −330 at promoter region of IL-2 gene was overrepresented in CSU. Heterozygotes (GT) at this locus and heterozygotes at +166 of IL-2 gene (GT) were more prevalent in CSU group. Additionally, the haplotype GT for loci −330 and +166 of IL-2 gene was powerfully associated with CSU (OR (95%CI) = 57.29 (8.43–112.7)). Conclusions SNP at position −330 and +166 of IL-2 gene are differently expressed in CSU. The haplotype GT of IL-2 at −330 and +166 might confer vulnerability to a number of immunological disorders in Iranian region.