Scientists have found that T-cells in the human body, which help protect the body from disease, can inadvertently destroy cells that produce insulin.

The findings offer better insight to the understanding of the causes behind Type 1 diabetes.

Professor Andy Sewell, an expert in human T-cells from Cardiff University's School of Medicine and diabetes experts from King's College London took a T-cell from a Type 1 diabetic patient to see a unique molecular interaction that results in the killing of insulin-producing cells in the pancreas.

"Type 1 diabetes is a result of the body's own immune system attacking and destroying the cells in the pancreas that manufacture the hormone insulin. Insulin controls blood sugar levels and a lack of insulin is fatal if untreated," said Professor Sewell in the journal Nature Immunology.

"The mechanism by which the body attacks its own insulin producing cells in the pancreas is not fully understood. Our findings show how killer T-cells might play an important role in autoimmune diseases like diabetes and we've secured the first ever glimpse of the mechanism by which killer T-cells can attack our own body cells to cause disease," he added.

The study brings researchers one-step closer in understanding diabetes and determining who gets it.

"This knowledge will be used in the future to help us predict who might get the disease and also to develop new approaches to prevent it. Our aim is to catch the disease early before too many insulin-producing cells have been damaged," said co-author of the study, Professor Mark Peakman frfom the National Institute for Health Research (NIHR) Biomedical Research Centre at King's College London and Guy's and St Thomas' NHS Foundation Trust.