Existing medication may reverse symptoms of type 1 diabetes

A medication that has long been used as a vaccination against tuberculosis and a treatment for bladder cancer may alleviate symptoms of type 1 diabetes, according to results from a clinical trial, which were presented recently at a meeting of the American Diabetes Association.

Denise Faustman, MD, PhD, medical director of the Massachusetts General Hospital Immunobiology Lab, found that bacillus Calmette-Guerin (BCG), which has been in use for more than 90 years, could significantly improve the treatment of type 1 diabetes.

In the clinical trial, Faustman and her team found that the medication speeds the death of autoreactive immune cells, which are known to kill insulin-producing cells in the pancreas. Furthermore, patients given BCG had higher levels of regulatory T cells and C-peptide, an indicator of insulin production.

The researchers said that previous studies have shown that BCG stimulates the production of a type of cell known as tumor necrosis factor. This cell kills abnormal immune system cells that attack healthy tissues rather than potentially harmful foreign bodies.

This hypothesis was confirmed in one of the patients who had type 1 diabetes but was given a placebo in the study. This patient became infected with the Epstein-Barr virus at one point during the study and saw an improvement in type 1 diabetes symptoms similar to that of patients who received the active medication. This infection is known to increase production of tumor necrosis factor.

Faustman said that her team's findings could provide hope of improving treatment of type 1 diabetes, even in patients who have had the condition for many years.

"Not only did we observe and measure the death of these self-targeting immune cells, but we also saw evidence of restoration of insulin production even in patients who've had type 1 diabetes for more than a decade," she said.