No Immunological Benefit of Selenium in Consecutive Patients with Autoimmune Thyroiditis

Abstract

Recently it has been demonstrated that after selenium (Se) supplementation in autoimmune thyroiditis (AIT) patients, there was a significant decrease of thyroid peroxidase (TPO) autoantibody (TPOAb) levels. The aim of our study was to evaluate the immunological benefit of Se administration in unselected AIT patients and thus address the question whether Se administration should generally be recommended for AIT patients. Thirty-six consecutive AIT patients (aged 19-85 years) were included in the present study. In addition to their levothyroxine (LT(4)) treatment, 18 patients received 200 microg (2.53 micromol) sodium selenite per day orally for the time span of 3 months, whereas 18 patients received placebo. All patients had measurement of thyroid hormones, thyrotropin (TSH), autoantibodies (thyroglobulin antibodies [TgAb] and TPOAb), Se levels, and intracellular cytokine detection in CD4(+) and CD8(+) T cells of peripheral blood mononuclear cells (PBMC) by flow cytometry before and after Se or placebo administration. No significant difference in the TPOAb levels was found after Se administration (524 +/- 452 vs. 505 +/- 464 IU/mL; p > 0.05). Furthermore, we found no significant differences in the CD4(+) or CD8(+) cytokine pattern (IFN-gamma, IL-2, IL-4, IL-5, IL-6, IL-10, IL-13, TNF-alpha, TNF-beta) in patients before and after Se administration, in patients before and after placebo administration and between Se group and placebo group before and after Se vs. placebo administration. We demonstrate that Se administration in our AIT patient's cohort does not induce significant immunological changes, either in terms of cytokine production patterns of peripheral T lymphocytes or of TPOAb levels. Our data suggest that AIT patients with moderate disease activity (in terms of TPOAb and cytokine production patterns) may not (equally) benefit as patients with high disease activity.