(HealthDay News) — A tuberculosis vaccine can reduce autoimmunity and increase insulin production in patients with long-term type 1 diabetes, according to a study published online Aug. 8 in PLoS One.
Building on previous studies in rodents showing that the Bacillus Calmette-Guerin (BCG) vaccine stimulates tumor necrosis factor production and stimulates innate immunity, Denise L. Faustman, M.D., Ph.D., from Massachusetts General Hospital in Boston, and colleagues randomly assigned six patients with long-term type 1 diabetes to BCG or placebo. Results were compared with six healthy controls as well as an additional 57 patients with type 1 diabetes and 16 healthy subjects.
The researchers found that, after 20 weeks, diabetes patients treated with BCG, as well as one healthy control who became infected with Epstein-Barr virus (EBV) after enrollment, had increased numbers of dead insulin-autoreactive T cells and induction of regulatory T cells. Levels of C-peptide, a measure of insulin production, also significantly and transiently increased in two BCG-treated diabetes patients and the EBV-infected healthy subject.
“We conclude that BCG treatment or EBV infection transiently modified the autoimmunity that underlies type 1 diabetes by stimulating the host innate immune response,” Faustman and colleagues write.