Association between IL17A/IL17RA Gene Polymorphisms and Susceptibility to Alopecia Areata in the Korean Population.

Background: Alopecia areata is marked by autoimmune assault on the hair follicle resulting in hair loss. T helper 17 cell subset has important roles in protecting the host against extracellular pathogens, however, also promotes inflammatory pathology in autoimmune disease, and it expresses both interleukin (IL)-17A and IL-17F, which can signal via the IL-17 receptor A.

Objective: To investigate the significance of IL17A and IL17RA gene polymorphisms in the susceptibility to alopecia areata.

Methods: We conducted case-control association study of 238 alopecia areata patients and 270 matched healthy controls. Allele frequency of total 2 single nucleotide polymorphims in the IL17A gene and 4 single nucleotide polymorphims in the IL17RA gene were studied. The statistical analyses were performed according to onset age, the presence of familyhistory, clinical subtypes, and presence of nail involvement or body hair involvement.

Results: One single nucleotide polymorphim (rs879577) of IL17RA gene showed significant difference between alopecia areata patients group and controls group (p= 0.0288). One single nucleotide polymorphim (rs4819554) of IL17RA gene showed significant difference between the early onset and late onset alopecia areata (p=0.0421).

Conclusion: IL17RA gene polymorphism might contribute to the increased susceptibility to alopecia areata in Korean population, and IL17RA gene polymorphism may be associated with onset age.