Cause of islet cell rejection discovered

TOKYO, Feb. 4 (UPI) -- Japanese scientists say they've identified the cause of early rejection of transplanted pancreatic islet cells used in treating type 1 diabetes.

The researchers at the Riken Institute and Fukuoka University said their discovery sets the stage for development of powerful new treatment techniques.

Currently, the most widely-used treatment for type 1 diabetes is the regular injection of insulin, the researchers said. While islet cell transplantation -- the transplantation of insulin-producing cells from a donor pancreas -- is a promising alternative approach, the scientists said the procedure has achieved only limited success due to a strong and rapid immune-mediated rejection of transplanted islets.

Now, in the new study, the researchers said they've demonstrated that HMGB1, a nuclear protein whose precise function has previously been unclear, is produced by the islet cells and directly triggers their early rejection.

Based on that finding, the scientists developed a system to measure the level of HMGB1 in the blood and determine the onset of rejection -- information they said they used to establish a treatment four times more effective than earlier islet transplantation protocols.

The study is reported in the Journal of Clinical Investigation.