Bacillus Calmette-Guerin in controlling type 1 diabetes: A quasi-experimental randomized clinical trial

T1DM is an autoimmune and chronic metabolic disorder characterized by the destruction of pancreatic beta cells. The Bacillus Calmette--Guérin (BCG) vaccine, originally used for tuberculosis prevention, has shown potential in modulating the immune response and improving beta-cell function. This study aimed to evaluate the therapeutic effects of two doses of BCG vaccine, administered four weeks apart, on glycemic control and selected immunological markers in patients with T1DM.

In this single-center, double-blind randomized clinical trial, 33 patients with T1DM were enrolled and randomly assigned to intervention and control groups in a 1:1 ratio, matched by age and sex. The intervention group received two intradermal doses of the BCG vaccine, with a four-week interval. Fasting blood samples were collected at baseline and during follow-up to assess biochemical and immunological parameters. Patients were followed-up for 18 months. IRCT identifier: IRCT20201012049003N1; (date of registration: 2020/10/15).

The mean age of participants was 11.25±3.32 years in the control group and 10.69±3.22 years in the BCG group. Anti-ICA levels significantly decreased in the BCG group by the end of the follow-up period. Although there was no significant difference in fasting blood glucose levels between the two groups, a significant reduction in HbA1c was observed in the BCG group after 18 months.

The findings suggest that BCG vaccination may contribute to improved long-term glycemic control, as evidenced by reduced HbA1c levels, in patients with T1DM. Additionally, the decrease in Anti-ICA levels indicates a potential immunomodulatory effect, supporting the therapeutic promise of BCG in autoimmune diabetes.