The combination of tumour necrosis factor-α -308A and interleukin-10 -1082G gene polymorphisms and increased serum levels of related cytokines: susceptibility to vitiligo.

ABSTRACT

BACKGROUND: The aetiopathogenesis of vitiligo is still under investigation. AIM: To assess the role of single nucleotide polymorphisms (SNPs) of the genes for tumour necrosis factor (TNF)-α, interleukin (IL)-6 and IL-10, as well as the serum levels of these three cytokines in the pathogenesis of vitiligo. METHODS: The study enrolled 105 patients with vitiligo, and 211 age- and sex-matched controls. TNF-α (-308), IL-6 (-174) and IL-10 (-1082) promoter polymorphisms were investigated by LightSNiP assay and analysed by χ(2) test. Subsequently, the serum cytokine levels were assessed by ELISA and evaluated by Mann-Whitney U-test and Kruskal-Wallis test. RESULTS: The frequency of the GG genotype of the IL-10 -1082 polymorphism was significantly higher in the vitiligo group compared with the healthy control group (P = 0.02). Further investigations using combinations of these variant alleles detected a significant risk for vitiligo for individuals carrying both the IL-10 -1082G and TNF-α -308A alleles (OR = 12.57, 95% CI 1.44-110.0, P < 0.01). Serum IL-10 and TNF-α levels were higher in the vitiligo group (P = 0.001). In addition, TNF-α levels in patients with active disease were significantly higher than in patients with stable disease (P < 0.02). CONCLUSIONS: The concomitant presence of IL-10 -1082G and TNF-α -308A alleles significantly raises the risk for vitiligo. Furthermore, in accordance with these findings, serum IL-10 and TNF-α were also increased in this study, confirming the role of these cytokines in the pathogenesis of vitiligo.