A very early finding of our research group was that the immune system started producing autoantibodies a very long time before someone developed diabetes. This suggests that, even if autoantibodies are present, there is a big ‘window of opportunity’ to delay or prevent type 1 diabetes if effective treatment to slow the underlying autoimmune process becomes available (Lancet 1981) This finding has provided the rationale for all the subsequent research aiming to prevent the condition.