Selenium status and over-expression of interleukin-15 in celiac disease and autoimmune thyroid diseases.

In celiac disease (CD), for its multifactorial nature, the target organs are not limited to the gut, but include thyroid, liver, skin and reproductive and nervous systems. Between the extraintestinal symptoms associated with CD, autoimmune thyroid diseases (AITDs) are more evident, underlining as CD-related autoimmune alterations can be modulated not only by gluten but also by various concurrent endogenous (genetic affinity, over-expression of cytokines) and exogenous (environment, nutritional deficiency) factors. In their pathogenesis a central role for over-expression of interleukin-15 (IL-15) is shown, by inhibiting apoptosis, leading to the perpetuation of inflammation and tissue destruction. Thyroid is particularly sensitive to selenium deficiency because selenoproteins are significant in biosynthesis and activity of thyroid hormones; besides, some selenoproteins as glutathione peroxidase are involved in inhibiting apoptosis. Thus, selenium malabsorption in CD can be thought as a key factor directly leading to thyroid and intestinal damage. Considering the complexity of this interaction and on the basis of available evidence, the aim of this review is to assess as preventive and therapeutic target the role of IL-15 and selenium in the pathogeneses of both CD and AITD.