Endocrine Abstracts

Introduction and aim: Cytokines play a crucial role in modulating immune response in both Hashimoto’s thyroiditis (HT) and Graves’ disease (GD). They may contribute to drive the autoimmune response skewing toward the Th17 phenotype and away from Th1 or Th2 phenotypes. Recent studies revealed an essential role of Th17 cells and their cytokines in the development of autoimmune thyroid diseases (AITD). However, participation of Th17 cells in the pathogenesis of GD is less evidenced. We aimed to assess the balance of Th17 immune response by analyzing plasma levels of Th17 associated cytokines in AITD patients.

Materials and methods: Fifty-four subjects were recruited into this study: 11 treatment naïve, newly diagnosed hyperthyroid GD patients, 30 patients with newly diagnosed euthyroid HT (4 out of 30 patients had mild subclinical hypothyroidism (TSH ≤ 6 µIU/ml)), and 13 age and sex-matched healthy subjects as controls. Cytokine patterns included following groups: Th17 cytokines – IL-17, IL-22; Th17-promoting cytokines – IL-23, IL-10 and IL-6. Plasma levels of cytokines were analyzed in all 54 participants. EDTA plasma immunological markers were detected by xMAP technology (Magpix system; Luminex Corporation, USA). All tests were performed in accordance with the manufacturer’s instructions (Cat#: HTH17MAG-14K; Kit Lot#: 3323752; Milliplex).

Results: The mean age of patients was 44.36 ± 15.41 years (28–72 years; nine females and two males) in GD group, 38.55 ± 12.54 years (23–64 years; 29 females and one male) in HT group, and 36.36 ± 11.91 years (22–58 years; 12 females and one male) in controls. Plasma IL-17 and IL-22 levels were 13.90 (10.26, 18.31) pg/ml, 0.04 (0.01, 0.35) ng/ml in HT group, 13.53 (10.34, 16.72) pg/ml, 0.13 (0.01, 0.25) ng/ml in GD group and 17.30 (12.23, 21.06) pg/ml, 0.18 (0.04, 0.51) ng/ml in controls, respectively. Median concentrations of IL-23, IL-10 and IL-6 were 2.42 (1.30, 3.68) ng/ml, 9.71 (5.96, 11.42) pg/ml, 3.12 (0.63, 14.18) pg/ml for HT patients, 2.32 (1.71, 3.36) ng/ml, 9.51 (6.55, 11.12) pg/ml, 6.93 (0.63, 24.90) pg/ml for GD patients and 3.30 (1.96, 4.21) ng/ml, 12.75 (7.63, 16.73) pg/ml, 11.29 (1.30, 15.67) pg/ml for controls, respectively. No significant difference was found between plasma levels of cytokines among the three groups.

Conclusions: Despite recent data on involvement of IL-23/IL-17 axis in the development of thyroid autoimmunity, we did not find any significant differences regarding plasma levels of Th17 associated cytokines between patients with AITD and control group.

This work was supported by Grant lzp-2018/2-0059.