Sodium/iodide symporter (NIS) and cytokines.

It has been shown that TSH upregulates rat NIS gene expression in vitro, and this induction can be modulated by cytokines. Analysis of the distribution of rat NIS mRNA ex vivo demonstrated variable levels of NIS transcription in different tissue samples. - IL-1beta and IL-6 have been found to decrease NIS mRNA expression in TSH-stimulated FRTL-5-cells. IL-6 has no effect on NIS functional activity, whereas IL-1beta suppresses iodide accumulation. The NIS is expressed in thyroid tissue of patients with autoimmune thyroid diseases, and its expression is increased in Graves' disease. With respect to other thyroidal autoantigens such as TPO and Tg, NIS obviously shows a very similar pattern to the well-described antigenic targets and may participate as an autoantigen in these diseases. Up to now only data of in vitro studies are available which started to evaluate the effects of different cytokines on NIS expression. The mechanisms of NIS regulation with respect to cytokine modulation in thyroid autoimmune disease remain still unproven and data of experimental in vivo studies and clinical trials in patients with thyroid autoimmune disease have to further elucidate these open questions in the future.