Endocrine Abstracts

Vitamin D plays an important role in the adaptive and innate immunity besides its skeletal effects. Some autoimmune disease is associated with vitamin D deficiency highlighting its crucial involvement in the onset of autoimmune diseases. This study investigated the relationship between the vitamin D supply and the serum IL-6, IL-17A and antibody levels against thyroid peroxidase (TPO) and TSH receptor in autoimmune thyroid diseases. Serum IL-6, IL-17A and antibody levels against TPO and TSH receptor were measured in 80 patients with autoimmune thyroid diseases (57 cases with Hashimoto’s thyroiditis, mean age of 48 ± 14 years and 23 cases with Graves’ disease, mean age of 48 ± 25 years, of whom 10 cases had ophthalmopathy). Data were displayed in geometric mean (95% confidence interval). No difference was found in vitamin D levels between the two groups of autoimmune thyroid deseases, but the serum levels in vitamin D deficient patients were significantly higher in Hashimoto’s thyroiditis compared with those in Graves’ disease [27.72 (10.4–73.91) vs 14.37 (2.53–81.57) nmol/l, P < 0.022]. Patients with hyperthyroid Graves’ ophthalmopathy demonstrated increased vitamin D levels compared with those in euthyroid state [43.87 (28.19–68.26) vs 18.26 (2.98–111.72) nmol/l, P < 0.0467]. The serum IL-6 [r = −0.27, P < 0.0423] and IL-17A [r = −0.3335, P < 0.0113] levels inversely correlated with the serum vitamin D levels and the vitamin D supply influenced them negatively in Hashimoto’s thyroiditis [18.54 (4.33–79.3) vs 8.23 (0.71–95.59) ng/ml, P < 0.0248 for IL-6 and 10.29 (3.92–27) vs 5.25 (1.44–19.22) ng/ml, P < 0.0031 for IL-17A levels between the patients with vitamin D deficiency and sufficiency]. The serum anti-TPO (r = 0.7452, P < 0.0054) and anti-TSH receptor antibody levels were positively influenced by the vitamin D supply in Graves’ disease, particularly in patients without ophthalmopathy [32.17 (3.24–319.28´) vs 394.97 (30.08–5186.02) IU/ml, P < 0.021 for anti-TPO and 1.54 (0.54–4.39) vs 6.64 (2.86–15.42) IU/l, P < 0.0299 for anti-TSH receptor antibody levels between patients with vitamin D deficiency and sufficiency]. The above mentioned relationships were also demonstrated by multivariate analysis in generalized linear model (GLM). Conclusions, the vitamin D levels influenced controversially the serum IL-6 and IL-17A levels in Hashimoto’s thyroiditis and positively the antibody levels againts TPO and TSH receptor inGraves’ disease demonstrating the difference in the activity of the adaptive immunity between these autoimmune thyroid diseases. The vitamin D supply can contribute to ameliorate the effects of inflammatory cytokines and amplify the antibody production against thyroid antigens.