Cause of type-I diabetes found, researchers say

WASHINGTON (Reuters) -- Researchers said Monday they had confirmed that type-I diabetes is triggered by the body's immune system turning on delicate cells, and they said they had found the cause.

The findings could lead to a type of vaccine against the disease that affects more than 1 million Americans, said Susan Wong and colleagues at Yale University School of Medicine.

Writing in the journal Nature Medicine, Wong's team said they found an antigen -- a protein that stimulates an immune response -- in mice specially bred to develop what looks like human juvenile diabetes.

There are two types of diabetes -- type-I, also known as juvenile diabetes, and type-II, known as adult-onset diabetes. Type-II diabetes is far more common and seems to be related to diet and a lack of exercise.

Type-I diabetes occurs when the immune system attacks the pancreatic beta cells that produce insulin for the body. People with type-I diabetes do not produce enough insulin and must carefully monitor their blood sugar levels and take insulin to control them.

There is no cure and failure to control blood sugar levels can cause blindness, limb loss and early death.

Finding just what it is that causes the body to attack these cells could help in the development of a cure.

They said much more work needs to be done, but it seemed that the immune system's T-cells attack an early form of insulin as it is produced by the body.

"This is the first report to our knowledge of the identification of an antigen that can stimulate islet-reactive CD8 T-cells, and it is likely to be a naturally processed peptide of preproinsulin," they wrote.

In a commentary, Christopher Benoist and Diane Mathis of the Institute of Genetics and Molecular Cellular Biology in Strasbourg called the findings "clear and provocative."

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