In the BB rat the disease is expressed in the pancreatic islet cells,20 and reducing the abnormal permeability that precedes this disease with AT-1001 can ameliorate the resulting diabetes.21 The current study has extended these observations by demonstrating that in the IL10−/− mouse abnormal small intestinal permeability not only precedes the development of colitis but it is also aetiologically important. This evidence concerns the gene IL10 and diabetes mellitus.