Aug. 8, 2012 -- Can an 80-year-old TB vaccine cure diabetes?

Maybe. A small clinical study found "proof of principle" that the BCG tuberculosis vaccine might help adults with long-standing type 1 diabetes.

Over a decade ago, Denise Faustman, MD, PhD, and colleagues at Massachusetts General Hospital and Harvard Medical School showed that the BCG vaccine worked in diabetic mice. By stimulating positive immune responses, the vaccine stopped the haywire immune responses that cause diabetes. Once this happened, the animals' insulin-making cells regenerated.

Other researchers duplicated the mouse studies. This led to "a lot of happy mice," Faustman says. But translating the findings to humans hasn't been easy. For starters, it required learning a lot more about the immune system and a lot more about type 1 diabetes.

It didn't look promising. A 1999 study found no effect of BCG vaccination in kids newly diagnosed with type 1 diabetes.

"When we started, there wasn't too much enthusiasm about trying to reverse diabetes in people 15 to 20 years out with this disease," Faustman tells WebMD.

She persisted.

"Surprisingly, our data was so good we got a signoff on doing a safety trial from the FDA," she says. "Even more surprising was that in this safety study, at a very low dose and after only two BCG vaccinations, we started seeing indications that this vaccine is doing the same thing in people as it does in the mouse."