One small study performed in rodents with type 1 diabetes has shown that the tuberculosis vaccine, bacillus Calmette-Guerin (or BCG) has triggered insulin secretion. This finding has led a separate team of researchers at the Massachusetts General Hospital to explore whether or not this vaccine will have a similar effect in humans.
The study in humans included six patients with long-standing type 1 diabetes in a double-blind, placebo controlled trial. Patients in the treatment group received the BCG vaccine, whereas the others received placebo. Blood was drawn on a weekly basis for 20 weeks in all patients. The blood was then analyzed for biomarkers of pancreatic function and immune system activity. At the end of the study some patients receiving the BCG vaccine showed elevated levels of C-peptide, a biomarker for insulin secretion.
Researchers suspect the BCG vaccine stimulates the body’s release of tumor necrosis factor (or TNF), which is thought to destroy the autoimmune cells attacking the pancreas in type 1 diabetes.
David Schoenfeld, PhD, one of the study’s researchers and a professor in the biostatistics department at Harvard Medical School, hesitates to refer to this discovery as a "diabetes vaccine" saying that "although BCG is a vaccine for tuberculosis, it was used in this study to alter the patients’ immune system rather than to prevent infection."
Faustman DL, Wang L, Okubo Y, Burger D, Ban L, et al. (2012) Proof-of-Concept, Randomized, Controlled Clinical Trial of Bacillus-Calmette-Guerin for Treatment of Long-Term Type 1 Diabetes. PLoS ONE 7(8): e41756. doi:10.1371/journal.pone.0041756