Promotion of IL‑17/NF‑κB signaling in autoimmune thyroid diseases

IL-17 and other cytokines have a number of immunomodulatory effects on thyroid cells. The present study investigated the changes and correlations amongst IL-17, NF-κB, IL-6, IL-10, interferon-γ (IFN-γ), TNF-α, IL-2 and IL-4 in patients with different autoimmune thyroid diseases in order to further clarify the pathogenesis of autoimmune thyroid disease. A total of 82 patients with autoimmune thyroid diseases (41 with Graves' disease and 41 with Hashimoto's thyroiditis) and 53 healthy controls were enrolled. All relevant thyroid hormones were detected by electrochemiluminescence analyzer. The serum levels of IL-17 and other cytokines were detected using flow cytometry, NF-κB was detected by ELISA, reverse transcription-quantitative PCR was used to detect the protein expression of various mRNAs, and the correlations between IL-17 and these factors were analyzed. Significant differences occurred amongst all groups. NF-κB, TNF-α, IL-6, IL-17 and their mRNA levels were significantly higher in the healthy controls compared with those in the patients; whereas IFN-γ and IL-10 levels were significantly lower in the healthy controls compared with those in the patients . Correlation analysis showed that the expression levels of IL-17 and its mRNA were significantly positively correlated with the expression levels of NF-κB, IL-6, thyroid peroxidase antibody, thyroid gland globulin, thyroglobulin antibody, TNF-α and IFN-γ, and were also significantly negatively correlated with IL-10 . These findings suggested that IL-17 was elevated in patients with autoimmune thyroid disease and that IL-17 could activate the NF-κB signaling pathway, stimulate the production and release of inflammatory factors such as TNF-α, IL-6 and IFN-γ and participate in the pathogenesis of autoimmune thyroid injury.