Association of IRF8 gene polymorphisms with autoimmune thyroid disease

Background: The occurrence of autoimmune thyroid disease (AITD) is known to have a major adverse effect on interferon (INF)-α treatment. The genetic variant of the INF regulatory factor 8 (IRF8), a type 1 INF regulator, is associated with susceptibility to systemic lupus erythematosus and multiple sclerosis. In this study, we investigated possible associations of the IRF8 polymorphisms, rs17445836 and rs2280381, with AITD in an ethnic Chinese population. Material and methods: In total, 278 patients with Graves' disease (GD) and 55 patients with Hashimoto's thyroiditis (HT), and 252 healthy controls were enrolled. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct sequencing were used for genotyping. Results: Significantly lower frequencies of the GA genotype and A allele of rs17445836 were found in the HT group than in the control group (P = 0·028, odds ratio (OR) = 4·71 and P = 0·022, OR = 4·40, respectively). Both rs17445836 and rs2280381 were associated with the presence of an antimicrosomal antibody (AmiA), and rs2280381 was also associated with the presence of an antithyroglobulin antibody (ATA) in AITD. Moreover, rs17445836 was associated with the level of AmiA in AITD. Conclusions: rs17445836 of IRF8 is a possible genetic variant associated with the development of HT. rs17445836 was associated with the production of thyroid antibody, and the GG genotype of rs17445836 was associated with a higher AmiA titre than the GA genotype.