**6.2 Vitamin D and type 1 diabetes: Direct effects on pancreatic cells**

1α,25 (OH)2 D3 appears to have a direct protective effect against pancreatic beta cell destruction by reducing the expression of MHC class I molecules (Hahn et al, 1997). In addition, vitamin D appears to increase islet cell expression of the A20 protein, which has antiapoptotic function (Riachy et al., 2002) (Fig 2). Vitamin D also decreases the expression of Fas, which is a transmembrane cell surface receptor mediator, involved in pancreatic beta cell apoptosis (Riachy et al., 2006).
