Proteins made by white blood cells in response to bacteria, viruses, and other substances. Antibodies and white blood cells are both components of the body’s immune system, which protects it from infections and diseases. Specific antibodies are designed to attack specific foreign proteins, or antigens.
Diabetes researchers now recognize that Type 1 diabetes is an autoimmune disease, in which the immune system mistakenly launches an attack on the beta cells of the pancreas. In the mid-1970’s, researchers in London first detected antibodies to pancreatic islet cells in people with newly diagnosed diabetes. These antibodies react to islet cell cytoplasm, the intracellular substance outside the nucleus of the cell, and thus came to be called islet cell cytoplasmic antibodies, or ICAs. Since that time, scientists have found a number of other antibodies in people who already have diabetes or who will develop diabetes in the near future, including ICA512 and antibodies to glutamic acid decarboxylase and to insulin.
Clinical researchers can now use tests for these antibodies to fairly accurately predict who will develop diabetes within a given period of time. More and more, using combinations of these antibody tests, researchers are gradually improving their ability to reliably predict the onset of diabetes. Better prediction, in turn, has allowed scientists to test a variety of approaches to prevention—approaches that previously had only been tried in animals. So far, the most notable effort has been the Diabetes Prevention Trial-Type 1 (DPT-1), which tested whether insulin given in low-dose injections or orally can prevent or delay the onset of diabetes in people at “intermediate” or “high” risk for developing it. The researchers recruited close relatives of people with Type 1 diabetes and then tested them for ICAs to predict their risk of developing diabetes. At the end of the trial, the researchers concluded that neither oral insulin nor injected insulin prevented or delayed diabetes.