Type 1 diabetes mellitus as a disease of the beta-cell (do not blame the immune system?)

Type 1 diabetes mellitus is believed to result from destruction of the insulin-producing beta-cells in pancreatic islets that is mediated by autoimmune mechanisms. The classic view is that autoreactive T cells mistakenly destroy healthy ('innocent') beta-cells. We propose an alternative view in which the beta-cell is the key contributor to the disease. By their nature and function, beta-cells are prone to biosynthetic stress with limited measures for self-defence. beta-Cell stress provokes an immune attack that has considerable negative effects on the source of a vital hormone. This view would explain why immunotherapy at best delays progression of type 1 diabetes mellitus and points to opportunities to use therapies that revitalize beta-cells, in combination with immune intervention strategies, to reverse the disease. We present the case that dysfunction occurs in both the immune system and beta-cells, which provokes further dysfunction, and present the evidence leading to the consensus that islet autoimmunity is an essential component in the pathogenesis of type 1 diabetes mellitus. Next, we build the case for the beta-cell as the trigger of an autoimmune response, supported by analogies in cancer and antitumour immunity. Finally, we synthesize a model ('connecting the dots') in which both beta-cell stress and islet autoimmunity can be harnessed as targets for intervention strategies.This Review examines the evidence that beta-cells are active participants in the dialogue with the immune system during the development of type 1 diabetes mellitus. The authors suggest that therapies targeting beta-cell health, vitality and function might prove essential, in combination with immunotherapy, to change the course of events leading to beta-cell destruction.Therapeutic cell differentiatio