Background: Hashimoto's thyroiditis (HT) is an autoimmune disease characterized by the destruction of thyroid cells through immune processes involving T helper (Th)1 cytokines. This clinical trial investigates the impact of vitamin D supplementation on serum cytokine levels and gene expression in CD4+ T cells from HT patients, aiming to understand its effects on Th-1, Th-2, Th-17, and regulatory T (Treg) cell-associated factors. Methods: Female patients were randomly assigned in a double-blind design to either a vitamin D-supplemented group, which received cholecalciferol [1, 25(OH)2D3] at a dose of 50,000 IU, or the placebo group, which received a weekly placebo for a duration of three months. Serum cytokine levels were assessed using enzyme-linked immunosorbent assay (ELISA), while genes’ expression levels were measured using real-time PCR. Results: Serum 25-hydroxyvitamin D and levels exhibited a significant increase following vitamin D supplementation, in comparison to the placebo group. Additionally, the vitamin D supplementation resulted in a significant elevation of serum calcium (Ca) levels compared to baseline. In the vitamin D group, there was a significant decrease in both serum levels and expression of the interleukin (IL)-17 gene when compared to baseline, although no statistical difference was observed between the placebo and vitamin D groups. The gene expression of transforming growth factor-beta (TGFβ) was significantly increased in the vitamin D group compared to baseline, with no significant difference between the two study groups. Vitamin D treatment had no effect on serum levels of interferon-gamma (IFNϒ) and IL-4. While the gene expression of IL-4 in the vitamin D group did not exhibit a statistically significant increase, the level of GATA3 transcription factor increased significantly when compared to the placebo group. The expression of IFNϒ and transcription factors, T-bet, RORc, and forkhead box protein 3 (FOXP3) in genes did not show significant changes following vitamin D supplementation. Conclusion: The findings suggest that vitamin D supplementation may hold potential benefits for autoimmune diseases, such as HT. However, further longitudinal clinical trials are necessary to gain a more comprehensive understanding of the specific effects of vitamin D on HT. Clinical Trial Registration Number: IRCT2016110130644N1.

中文翻译：

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女性桥本甲状腺炎患者补充维生素 D 后 CD4+ T 细胞细胞因子谱的变化：一项双盲、随机临床试验

背景：桥本甲状腺炎 (HT) 是一种自身免疫性疾病，其特征是通过涉及 T 辅助细胞 (Th)1 细胞因子的免疫过程破坏甲状腺细胞。该临床试验研究补充维生素 D 对 HT 患者血清细胞因子水平和 CD4+ T 细胞基因表达的影响，旨在了解其对 Th-1、Th-2、Th-17 和调节性 T (Treg) 细胞的影响-相关因素。方法：采用双盲设计将女性患者随机分配至补充维生素 D 组（接受剂量为 50,000 IU 的胆钙化醇 [1, 25(OH)2D3]）或安慰剂组（每周接受一次剂量）。安慰剂持续三个月。使用酶联免疫吸附测定（ELISA）评估血清细胞因子水平，同时使用实时PCR测量基因表达水平。结果：与安慰剂组相比，补充维生素 D 后血清 25-羟基维生素 D 及其水平显着增加。此外，与基线相比，补充维生素 D 导致血清钙 (Ca) 水平显着升高。在维生素 D 组中，与基线相比，血清水平和白细胞介素 (IL)-17 基因的表达均显着下降，但安慰剂组和维生素 D 组之间没有观察到统计学差异。与基线相比，维生素 D 组的转化生长因子-β (TGFβ) 基因表达显着增加，但两个研究组之间没有显着差异。维生素 D 治疗对干扰素-γ (IFNϒ) 和 IL-4 的血清水平没有影响。虽然维生素 D 组中 IL-4 基因表达没有表现出统计学上显着的增加，但与安慰剂组相比，GATA3 转录因子的水平显着增加。补充维生素 D 后，基因中 IFNϒ 和转录因子、T-bet、RORc 和叉头盒蛋白 3 (FOXP3) 的表达没有显示出显着变化。结论：研究结果表明，补充维生素 D 可能对治疗 HT 等自身免疫性疾病具有潜在益处。然而，需要进一步的纵向临床试验才能更全面地了解维生素 D 对 HT 的具体作用。临床试验注册号：IRCT2016110130644N1。