What Roles Do Antibodies Play in Diabetes?

Adult diabetic testing blood glucose levels
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Diabetes often goes unnoticed until it reaches an advanced stage, but experts believe that early diagnosis is critical to provide the best treatment. To aid in earlier diagnosis, diabetes researchers are investigating genetic markers that could predict a person's risk for developing diabetes long before the disease process is underway. One area of particular interest is the role of antibodies.

Antibodies in Diabetes

Antibodies are specialized proteins found in the blood and elsewhere in the body. Antibodies detect and attack foreign substances in the body, such as viruses and bacteria. Occasionally, antibodies malfunction and attack the body's own systems. When this occurs, the malfunctioning antibodies are called autoantibodies. Frequently, in patients with type 1 diabetes, autoantibodies attack and destroy insulin-producing islet beta cells in the pancreas. This type of attack on the immune system can also occur in patients with type 2 diabetes, but less often.

Scientists have identified several antibodies that seem to be related to the development of diabetes, including glutamic acid decarboxylase 65 antibodies (GADA) and islet cell antibodies (ICA). These antibodies fight unwanted proteins in and on the islet beta cells.

In some cases, people who have type 1 diabetes have higher levels of antibodies to fend off an outside attack, along with autoantibodies that attack the body's own systems. The autoantibody attack is believed to destroy the very islet cells that the antibodies protect.

Ninety-five percent of children diagnosed with type 1 diabetes have high levels of ICA and autoantibodies of GADA. Up to 25% of people with adult-onset type 2 diabetes have elevated levels of these autoantibodies.

Antibodies in Early Screening

Recent research has shown that the presence of autoantibodies of GADA can be a strong predictive marker for the eventual onset of type 1 diabetes. In many cases, these autoantibodies are present before the symptoms of diabetes or prediabetes set in. Using a blood test to screen for these autoantibodies -- particularly in siblings of those already diagnosed with type 1 diabetes -- may help predict whether a person is at risk of developing diabetes and which type of diabetes that may develop. Such early detection may enable preventive measures to stall the onset of the disease.

Antibodies in Diabetes Management

Many people develop type 2 diabetes because they are overweight and have a sedentary lifestyle. However, some of the individuals with type 2 diabetes can have antibodies and autoantibodies at levels as high as or even higher than those who have type 1 diabetes. Patients diagnosed with type 2 diabetes may wish to undergo blood tests to determine if they have any autoantibodies present in their bodies. Type 2 diabetics with high levels of autoantibodies may be more likely to require insulin in the future. This information may help predict the course of their disease and whether they may eventually require insulin injections to manage their diabetes.

Latent Autoimmune Diabetes of Adulthood: 'In-between' Diabetes

Some people develop adult-onset diabetes that initially appears to be type 2 diabetes and responds to oral diabetic medications. However, within a few years, these medications lose their effectiveness and patients must begin using insulin. This form of diabetes is sometimes called latent autoimmune diabetes of adulthood (LADA), which is sometimes also referred to as "the in-between diabetes" or type 1.5 diabetes because it begins as type 2 diabetes before becoming the insulin-dependent type 1 diabetes.

People with LADA have higher levels of ICA and GADA, as well as higher levels of the malfunctioning autoantibodies. Over time, the autoantibodies overwhelm the antibodies, destroying the body's ability to produce insulin. When this happens, type 2 diabetes then becomes type 1 diabetes.

Experts believe that because individuals with LADA have high levels of properly functioning antibodies, their immune systems are able to suppress the autoantibodies more effectively and for a longer period of time than people who were originally diagnosed with type 1 diabetes at an early age. However, over time the autoantibodies of people with LADA destroy the body's ability to produce insulin. Therefore, insulin dependency develops more rapidly in the LADA patient than in the typical type 2 diabetic patient.

It should be noted that some individuals may have both types of these malfunctioning autoantibodies and yet never develop either form of diabetes. In addition, it is important to remember that the most significant risk factors for type 2 diabetes -- diet and weight -- have nothing to do with malfunctioning of the immune system, and these factors can be controlled with a healthy lifestyle.

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