Gene-Edited Islet Cells Show Promise in First Human Transplant Without Immunosuppression

For decades, islet cell transplantation has held promise as a potential treatment for Type 1 diabetes. The challenge has always been the same: when donor cells from another person are placed into a patient, the recipient's immune system recognizes them as foreign and attacks them. To prevent this rejection, patients must take immunosuppressive medications—drugs that can cause their own set of serious side effects over time.

A team led by Per-Ola Carlsson at Uppsala University in Sweden has reported a different approach. Instead of relying on immunosuppressive drugs to protect transplanted islet cells, they genetically modified the cells themselves to avoid immune detection. The result, published in The New England Journal of Medicine, offers an early glimpse of what may be possible.

The strategy involved using CRISPR gene-editing technology to create what researchers call 'hypoimmune' islet cells. These cells were engineered to hide from both the innate and adaptive immune systems—the two main branches of immune defense.

The transplanted cells, known as UP421, came from human pancreatic islets obtained from deceased organ donors. Researchers made two key genetic changes. First, they added extra copies of a gene for a protein called CD47, which acts as a 'don't eat me' signal to immune cells. Second, they removed genes responsible for producing human leukocyte antigens (HLA), markers that the adaptive immune system uses to identify foreign material.

Together, these modifications aimed to make the donor islet cells invisible to the recipient's immune system. The idea is elegant: if the immune system cannot recognize the cells as 'foreign,' it will not attack them—and the patient will not need immunosuppressive drugs.

One man with Type 1 diabetes who had lived with the condition for at least 5 years received an intramuscular transplant of the modified islet cells. He did not take any immunosuppressive medications before, during, or after the procedure.

At 3 months, researchers found that the transplanted cells were producing insulin in response to changes in blood glucose—exactly what they should do. The patient showed no immune response against the gene-edited cells, and no serious adverse events occurred.

New data from 14 months post-transplant extend these encouraging early findings. The patient's transplanted cells continued to function and respond appropriately to glucose levels. Over the entire follow-up period, the patient experienced six adverse events overall, including two mild cases of pharyngitis, but none were serious or related to the transplanted cells.

This first-in-human study suggests that genetically modified donor islet cells may be able to survive and work without immunosuppression. If this approach proves durable and can be successfully replicated in other patients, it could eventually offer Type 1 diabetes patients a way to regain stable glucose control without the burden of lifelong immune-suppressing medications.

However, it is important to recognize the current limits of the evidence. This is a single patient followed for 14 months. Researchers do not yet know whether the transplanted cells will continue to function long-term, whether the approach will work for other patients, or what factors might influence success or failure. Additional studies will be needed to answer these questions and to understand the true potential of this strategy.

The research team is continuing to monitor this patient and plans to enroll more participants in clinical trials. The work builds on earlier laboratory and animal studies showing that hypoimmune islet cells can engraft and function in immunocompetent recipients—but human outcomes are always the ultimate test.

This advance is part of a larger effort in diabetes research to develop cell-based therapies that could replace damaged or missing beta cells. The scarcity of available donor pancreases and islets for transplant has long been a limiting factor. Gene-edited cells engineered to avoid rejection could potentially increase the supply of available transplant material and improve outcomes for patients.

Parallel research efforts are also exploring islet transplants from genetically modified pigs (xenotransplantation) and islet cells protected by biocompatible encapsulation. Each approach has its own advantages and challenges, but they all share the same goal: to provide people with Type 1 diabetes access to a more effective treatment option with fewer side effects.

Origin: springermedicine.com (News report). Evidence: News report, corroborated with 3 indexed studies. Type1Cure is an information and intelligence hub, not a medical advice service. This article summarizes published research and does not provide diagnosis, treatment, or personal medical guidance. Always talk to your own care team before changing anything about your Type 1 diabetes management.