Scientists have found that bacterial infection may have a role to play in the development of type 1 diabetes, as it can trigger the immune system to destroy insulin-producing cells.
The findings, which has improved the understanding about the mechanisms involved in the development of type 1 diabetes, could help experts to diagnose or even prevent the condition.
Killer T-cells are white blood cells which the body uses to fight bacterial infection.
This latest research shows that killer T-cells, when activated by bacteria, can trigger the development of type 1 diabetes.
The team found that proteins from bacteria may generate killer T-cells, which then attack insulin-producing cells.
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Study lead Professor Andrew Sewell, from Cardiff University’s School of Medicine, said: “Type 1 diabetes is an autoimmune disease that usually affects children and young adults, where the cells that produce insulin are attacked by the patient’s own immune system. This leads to a lack of insulin, meaning that people living with type 1 diabetes need to inject insulin multiple times a day to control their blood sugar levels.
“There is currently no cure for type 1 diabetes and patients require life-long treatment.
“People living with type 1 diabetes may also develop medical complications later in life, so there is an urgent need to understand the underlying causes of the condition to help us find better treatments.”
The study involved bacterial proteins being added to cell lines from healthy donors, with researchers closely monitoring how the killer T-cells reacted. They observed that this interaction with the proteins prompted killer T-cells to attack insulin-producing cells.
The study’s clinical lead, Dr Lucy Jones, said: “We observed this in relation to a specific HLA – human leukocyte antigen – a gene that codes for proteins that help the immune system differentiate between our own cells and invading cells.
“The specific HLA associated with the bacterial infection that triggers diabetes is only present in around 3% of the population in the UK. So the bacterial pathogens that can generate anti-insulin T-cells are caused by a rare infection in a small minority of people.”
The study follows previous research by the team, which highlighted the important role that killer T-cells play in triggering type 1 diabetes through the attack on insulin-producing cells.
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Professor Sewell explained the latest findings: “Killer T-cells are able to target and attack body cells that produce a specific protein. We found that after encountering proteins from some infectious bacteria, killer T-cells could mistakenly also kill cells producing the insulin protein.
“We found activated T-cells with this same ‘cross-reactivity’ in the blood of patients with type 1 diabetes suggesting that what we saw in laboratory experiments could have triggered the disease.”
The study’s first author, Garry Dolton, said they hoped that understanding how T-cells trigger diseases like type 1 diabetes will allow experts to diagnose and treat disease before the onset of symptoms, adding: “Early treatment is known to result in a better prognosis as the healthy pancreatic beta cells that are being attacked can be protected before they are destroyed.”
Read more in the Journal of Clinical Investigation.
