Two years after beginning a ground-breaking phase II clinical trial in reversing Type I diabetes, researchers from Massachusetts General Hospital have discovered that a TB vaccine could permanently reverse diabetes.
Director of the Massachusetts General Hospital Immunobiology Laboratory and Principal Investigator of the trial, Dr Denise Faustman, presented the findings of the clinical trials at the 75th Scientific Sessions of the American Diabetes Association.
In the study carried out on mice, the researchers used the Bacillus Calmette-Guerin (BCG) vaccine, an inexpensive and already generic vaccine that is used around the world to prevent TB.
Dr Faustman said the BCG could induce a permanent gene expression that restores regulatory T cells (Tregs), helping to prevent the immune system attack which characterises Type I diabetes.
The potential to activate these cells is important because Type I diabetes occurs when the immune system mistakenly attacks insulin-secreting islets in the pancreas. Tregs have the ability to halt this aberrant behaviour, but effective methods for modulating their activity have yet to be found.
According to the researchers, the theory could also work in other autoimmune disorders, such as multiple sclerosis (MS).
“BCG is interesting because it brings into play so many areas of immunology that we as a community have been looking at for decades, including Tregs and the hygiene hypothesis,” said Dr Faustman.
“Repeat BCG vaccination appears to permanently turn on signature Treg genes, and the vaccine’s beneficial effect on host immune response recapitulates decades of human co-evolution with mycobacteria, a relationship that has been lost with modern eating and living habits,” continued Dr Faustman.
Faustman’s team was the first to document Type I diabetes reversal in mice and in a subsequent phase I trial demonstrated successful human clinical results who had received the BCG vaccination. The phase II trial will enrol 150 adult patients and run for five years. Long-term data from the study is expected to be published later this year.