Association Between Polymorphisms of IL-23/IL-17 Pathway and Clinical Phenotypes of Autoimmune Thyroid Diseases.

Several autoimmune and inflammatory disorders, including autoimmune thyroid diseases (AITD), have been linked to Th17 cells and the IL-23/IL-17 axis. Current data suggest that genetic variation contributes greatly to disease susceptibility to AITD.To study the role of single nucleotide polymorphisms (SNPs) of IL-23/IL-17 pathway in AITD predisposition and test the gene-gene/gene-sex interactions in these loci.A total of 1051 patients with AITD, including 657 patients with Graves' disease (GD) and 394 patients with Hashimoto's thyroiditis (HT), and 874 healthy controls were enrolled in this case-control association study. Six SNPs were selected and genotyped by multiplex PCR combined with high-throughput sequencing. Interactions were tested by the general multifactor dimensionality reduction (GMDR) method.Allele C and combinational genotype AC+CC of rs3212227 within IL-23 were significantly associated with GD with goiter (p=0.003 and 0.014, respectively). Allele G and combinational genotype AG+GG of rs4819554 within IL-17RA were significantly related to HT with family history and the severity of HT (p=0.011 and 0.027; p=0.041 and 0.035). Also, allele T and genotype CT+TT of rs9463772 within IL-17F were significantly correlated with the severity of HT (p=0.001 and 0.027, respectively). Moreover, high dimensional gene-sex interaction (IL-23R-IL-23-IL-17RA-IL-17F-sex) was identified in AITD, GD, and HT patients with GMDR analysis.Our study identified the novel loci and gene-sex interaction in AITD. This evidence, from another perspective, suggests that sex, IL-23/IL-17 pathway, and Th17 cells play an important role in the pathogenesis of AITD.