New research has discovered a promising way to maximise the benefits of islet transplants for people living with type 1 diabetes, by 'match-making' donors and recipients.
An islet transplant is when clusters of insulin-making beta cells from a donor pancreas are transplanted into someone with type 1 diabetes.
Islet transplants can help people with type 1 diabetes to produce insulin again and have steadier blood sugar levels, as well as bringing back hypo awareness.
But the type 1 diabetes immune attack is still active, so people who have islet transplants need to take drugs that dial down the immune system to protect the donated cells.
Because donor cells are in short supply, very few people can currently benefit from islet transplants. This means it’s critical to give these precious cells the best chance of survival, to boost the benefits of this life-changing treatment.
Medical match-making
Human Leukoctye Antigens (HLA) are proteins found on the surfaces of cells. They’re signals that the immune system uses to figure out which cells belong in your body and which don’t, and need to be destroyed.
We all have lots of different HLA types. Checking for HLA ‘matches’ between an organ donor and the person receiving the organ transplant is an important process.
If a donor and recipient aren’t a good match – meaning they don’t have similar HLA types – the body is more likely to reject the new organ. But at the moment, unlike in other organ transplants, doctors don’t use HLA matching to match up islet transplant donors and recipients.
Professor Shareen Forbes is an expert in islet transplants at the University of Edinburgh. We’ve been funding Prof Forbes for over a decade to find ways to maximise the benefits of islet transplants for people with type 1 diabetes.
In her latest study, she wanted to explore if donors’ and recipients’ HLA types could impact how well islet transplants worked. Specifically, she focused on a group of HLA types that we know are linked to type 1 diabetes.
What they found
The team looked at 268 people with type 1 diabetes who’d had islet transplants in Canada. They’d received donated islets from between one and three different donors.
The team analysed all the recipients and donors for their HLA types and followed them over 18 years to check how successful the transplants had been. They measured this by monitoring the participants’ blood sugar levels and how much insulin the transplanted cells were making.
The team found that the transplant recipients’ HLA types didn’t seem to influence whether the transplant was successful or not. But the donors’ HLA types did.
The researchers found that the recipients who got islets from donors who had a particular HLA type (called HLA-DQ8) had better transplant outcomes than those who did not. The donated islets seemed to survive and produce insulin for longer.
The researchers think this might be in part because this HLA type could help to hide transplanted islets from the immune system, protecting them from attack.
They also found another donor HLA type that seemed to be linked with less successful transplants, with islets more likely to fail over time.
Towards a new era of type 1 treatments
We now need more research to confirm these findings, but this research sheds new light on the potential value of HLA matching in islet transplants.
It also suggests that choosing donors who have the HLA-DQ8 signal might be a new way to maximise the success of islet transplants for people living with type 1 diabetes.
Beyond islet transplants, these new insights could also help researchers to grow stronger beta cells in the lab. Or to develop better immunotherapies that reprogramme the immune system to slow or stop type 1 diabetes from progressing.
Elsewhere, Prof Forbes is also leading a team to study even more innovative ways to unleash the benefits of islet cell transplants in a new project recently funded by the Type 1 Diabetes Grand Challenge.
With more and more scientists teaming up to tackle type 1 diabetes, we’re moving closer to the day where daily insulin injections and constant blood sugar monitoring are things of the past for people with type 1 diabetes.
