LOS ANGELES – Preliminary experiments in a handful of people suggest that it might be possible to reverse Type 1 diabetes using an inexpensive vaccine to stop the immune system from attacking cells in the pancreas.

Research in mice had already shown that the tuberculosis vaccine called BCG prevents T cells from destroying insulin-secreting cells, allowing the pancreas to regenerate and begin producing insulin again, curing the disease.

Now tests with very low doses of the vaccine in humans show transient increases in insulin production, researchers will report Sunday at a San Diego meeting of the American Diabetes Association.

The Massachusetts General Hospital team is now gearing up to use higher doses of the vaccine in larger numbers of people in an effort to increase and prolong the response.

The findings contradict an essential paradigm of diabetes therapy — that once the insulin-secreting beta cells of the pancreas have been destroyed, they are gone forever. Because of that belief, most research today focuses on using vaccines to prevent the cells’ destruction in the first place, or on using beta-cell transplants to replace the destroyed cells.

The new findings, however, hint that even in patients with long-standing diabetes, the body retains the potential to restore pancreas function if clinicians can only block the parts of the immune system that are killing the beta cells.

The results are “fascinating and very promising,” said immunology expert Dr. Eva Mezey, director of the adult stem cell unit at the National Institute of Dental and Craniofacial Research. But Mezey noted that the results have been achieved in only a small number of patients and that they suggest that the vaccinations will have to be repeated regularly.

Dr. Denise Faustman of Massachusetts General Hospital and her colleagues have been working with the BCG vaccine, which has been used for more than 80 years in relatively low doses to stimulate immunity against tuberculosis.

“If this is reproducible and correct, it could be a phenomenal finding,” said Dr. Robert R. Henry of the University of California, San Diego, who chaired the scientific program at the meeting. It suggests that once the destructive immune response is controlled, the body has the capability to produce more insulin, he said.