According to Reuters, a vaccine that has been used to treat tuberculosis, Bacillus Calmette Guerin (BCG), is now being considered to treat type 1 diabetes. In type 1 diabetes, insulin releasing pancreatic beta cells are thought to be killed off by harmful T cells. So, the vaccine Bacillus Calmette Guerin, is thought to work by eliminating those harmful T cells by increasing levels of tumor necrosis factor (TNF). Preliminary studies show that when two doses of the vaccine were given four weeks apart, patients had a temporary slight increase in insulin release. Moving forward, the FDA has approved a mid stage trial of 150 people with type 1 diabetes.