Lack of association of IL-10 (rs1800896) and IL-13 (rs1800925) with non-segmental vitiligo susceptibility in South Indian population.

BACKGROUND

Vitiligo is an autoimmune depigmentation disorder caused by multiple etiologies. Genetic polymorphisms in cytokine genes influence their expression and augment disease development. Analyzing the influence of genetic polymorphisms will help in better understanding of the complex etiopathogenesis of vitiligo.

AIM: To study the influence of interleukin IL-10 (rs1800896) and IL-13 (rs1800925) polymorphisms on vitiligo risk in South Indian population.

METHODS

Two hundred and sixty-four vitiligo patients and 264 controls were recruited in this study. Genotyping was done by quantitative PCR and plasma cytokine levels were measured by ELISA.

RESULTS

Allele frequencies of IL-10 (rs1800896) and IL-13 (rs1800925) SNPs were observed to be equal in the groups. Mutant allele G of IL-10 (rs1800896) enhanced the familial inheritance of vitiligo (P < 0.0001, OR-25.1, 95% CI-7.64-82.7) and influenced the development of vulgaris type of vitiligo (P = 0.034, OR-1.83, 95% CI-1.07-3.13). Ancestral allele A of IL-10 (rs1800896) conferred protection against development of acrofacial vitiligo (P = 0.04, OR-0.56, 95% CI-0.33-0.95). Circulatory IL-10 levels in vitiligo patients were higher than controls (P < 0.0001). Individuals with genotype GG of IL-10 (rs1800896) had the highest circulatory levels of IL-10 (P < 0.0001). Among the genotypes of IL-13 (rs1800925) variant, none influenced the phenotype of nonsegmental vitiligo such as gender, family history, age of onset and types of vitiligo (P > 0.05). In addition, no difference was noted in the circulatory levels of IL-13 between patients and controls (P = 0.48). Within patients, CC genotype of IL-13 (rs1800925) was observed to enhance the circulatory IL-13 levels (P < 0.0001).

LIMITATION: Replication group analysis in a larger multicentric cohort in future would validate further understanding of vitiligo susceptibility in South Indian ethnics.

CONCLUSION

IL-10 (rs1800896) and IL-13 (rs1800925) polymorphisms did not confer risk to develop vitiligo in South Indian population.