Germs could cause type 1 diabetes, study suggests

Germs could play a role in the development of type 1 diabetes, according to researchers at Cardiff University.
There is little understanding regarding what causes type 1 diabetes, but scientists have previously shown that a type of white blood cell, known as killer T-cells, plays a key role. Killer T-cells normally protect us from bacteria, but in type 1 diabetes they mistakenly attack the insulin-producing beta cells in the pancreas.
This new research found that the same killer T-cells that cause type 1 diabetes are strongly activated by some bacteria. They believe this bacteria could then trigger the body’s immune system to destroy its insulin-producing cells.
A study team from Cardiff’s Systems Immunity Research Institute previously found that an isolated killer T-cell from a patient with type 1 diabetes was highly ‘cross-reactive’. This means it can respond to a variety of triggers, and researchers hypothesised that a pathogen could stimulate T-cells to initiate type 1 diabetes.
They confirmed this theory after shining intense, powerful X-rays into samples of killer T-cells. Not only does this provide evidence of how germs might trigger type 1 diabetes, but it could steer scientists towards investigating more general mechanisms as causes of other autoimmune diseases.
Lead author Professor Andy Sewell, said: “During type 1 diabetes, killer T-cells are thought to attack pancreatic beta cells. These cells make the insulin that is essential for control of blood sugar levels.
“However, sometimes these sensors recognise the wrong target, and the killer T-cells attack our own tissue. We, and others, have shown this is what happens during type 1 diabetes when killer T-cells target and destroy beta cells.
“In this new study, we wanted to find out what was causing these T-cells to kill beta cells. We identified part of a bug that turns on killer T-cells so they latch onto beta cells. This finding sheds new light on how these killer T-cells are turned into rogues, leading to the development of type 1 diabetes.”
The research team hope that their findings will lead to new ways of diagnosing, preventing or even halting type 1 diabetes.
The study is published in The Journal of Clinical Investigation.