Dissociation between Fas expression and induction of apoptosis in human islets of Langerhans

There is increasing evidence that inappropriate induction of apoptosis in p ancreatic beta-cells may precede the development of type 1 diabetes in anim al models and in man. One mechanism by which this has been proposed to occu r involves up-regulation of the death receptor Fas on beta-cells, resulting in apoptosis of the Fas-bearing beta-cells upon ligation of the receptor. We have examined this hypothesis in isolated human islets of Langerhans and show that--in contrast to data obtained with rodent beta-cells-expression of Fas per se is not sufficient to allow induction of apoptosis upon additi on of agonistic anti-Fas serum.