This test is used to measure the presence of antibodies against Insulin.It is performed if a person is diabetic and the Insulin no longer seems to control the diabetics,or the person appears to have an allergic response to the Insulin.This test measures immune system's response to insulin and the different types of cells present. Hence the test may be used to confirm insulin resistance.The presence of anti-insulin antibodies (AIA) in diabetics treated with insulin has been recognized.The highly purified insulin preparations ,presently available , are less immunogenic than some of the previously used ,less pure preparations .Bovine insulin is more immunogenic than the porcine hormone.Also,it has recently been recognized that AIA may develop, in patients treated with human insulin.
CLINICAL SIGNIFICANCE
If lgG and lgM antibodies agaist insulin are elevated, the body recognizes the insulin to be foreign and may make the insulin less effective or neutralize the insulin. Also the antibodies may change the time that the insulin acts and hence the person may be at risk for low blood sugar. This means that the insulin cnnot serve its intended function of moving glucose from the blood stream into the cells As a result, increased levels of insulin are required for the same therapeutic effect. This phenomena is called insulin resistance.
If the test shows elevated values of IgE antibody against insulin, then the body has developed an allergic response to the medication.This could lead to risk for skin reactions or rarely more severe widespread reactions. Other medications such as antihistamines or low dose injectable steroids may help to lessen the reaction. If reactions have been severe, an in-hospital procedure called desensitization may be necessary.
In this condition, several different autoantibodies against normal tissues are found.These antibodies are associated with the destruction of the beta cells of the pancreas, although their exact role is uncertain.Some of the antibodies, which are found in diabetes patients, include islet cell antibodies (ICAs), anti- insulin antibodies (AIAs) and anti-GAD antibodies.These antibodies can be detected by RIA.
The determination of circulating anti- insulin antibodies is of clinical importance for the following reasons;
- The presence of free anti- insulin antibodies in plasma interferes with the determination of insulin by radioimmunoassay;
- At very high titers, the anti-insulin antibodies may induce a state of insulin resistance;
- Anti-insulin antibodies may influence the quality of the glycemic control, in diabetic patients,by prolonging the half life of insulin;
Type 1 diabetes is the most common outcome in case of anti-insulin antibodies. It is an autoimmune disease that results in chronic insulin deficiency .Components of the insulin-producing beta cells in the pancreas are attacked by the body's immune system. This immune attack ,by special white blood cells called Tymphocytes (T cells ) leads to destruction of beta cells.
Loss of functioning beta cells leads to hyperglycaemia (high blood glucose ) and frequently to longer-term complications involving the small blood vessels ( eyes, kidneys ) and large blood vessels (heart, limbs ) and nerves.