It is well appreciated that organ-specific autoimmune diseases run in families, but that within a family one member may have type 1 diabetes, another autoimmune thyroid disease, and another multiple sclerosis 1. What causes clustering of different autoimmune diseases along genetic lines, and what logic causes the immune system to take aim at different organ targets? In this issue, Salomon et al. make the paradoxical finding that interference with a single costimulatory molecule, B7-2, shifts the aim of autoimmunity in the NOD mouse strain away from the pancreatic islet β cell and onto the peripheral nerves 2. The finding adds an important molecular clue to the pathogenesis of organ-specific autoimmune disease, and illustrates the caution that will be needed as new immunological interventions are applied in the clinic.
The inheritance of susceptibility to organ-specific autoimmunity is extraordinarily...
