There is, in addition, a further possibility that combines both of these concepts since it is known that MHC-I molecules can be exported from cells under certain conditions, including type 1 diabetes.70 Our own unpublished data imply that β-cells retain this capacity and it is conceivable (but not proven) that MHC-I molecules bearing antigenic peptides might be secreted from β-cells during type 1 diabetes thereby generating a chemoattractant gradient to autoreactive CD8+ T-cells. This evidence concerns the gene CD8A and type 1 diabetes mellitus.