Nearly 100 years after it was developed, the Calmette-Guerin (perhaps better known as the BCG) vaccine continues to astonish scientists with its far-reaching impact on the human immune system. In the latest research, a team from the Massachusetts General Hospital Immunobiology Laboratory show how exposure to the bacteria in the vaccine can restore normal blood sugar levels in patients with type 1 diabetes (T1D) by boosting the appetite of white blood cells.
The as-of-yet unpublished insights, set to be presented today at the European Association for the Study of Diabetes 2018 Annual Meeting, build upon previous work suggesting that one contributing cause of T1D – an autoimmune disease wherein the body attacks its own insulin-producing cells – may be insufficient exposure to things the immune system is actually meant to target.
"It has long been believed that the move to cleaner and more urban environments is involved in not only how type 1 diabetes develops, but increased incidence of the disease," lead author Dr Denise Faustman said in a statement.
"In particular, reduced exposures to certain microbes, the consequence of better sanitation, greater use of antibiotics, smaller family sizes, cleaner houses, less daily exposures to the soil, and less exposure to domesticated animals, appears to have changed the modern metabolic function."
The BCG vaccine, which protects against tuberculosis by introducing a harmless, weakened lineage of bacteria closely related to Mycobacterium tuberculosis, has been shown to have the unintended but incredibly beneficial side effect of jumpstarting the human immune system as a whole. Past research has shown that BCG can help people fight a variety of conditions, including many types of cancers and parasitic infections.
Based on evidence that BCG is also beneficial for mitigating autoimmune disorders, Dr Faustman’s group initiated a small clinical trial wherein adults with T1D were given two BCG vaccines four weeks apart or two placebo shots. Four years later, the vaccinated subjects’ (n=9) average blood sugar level had dropped by over 18 percent, nearly back to non-disease levels, without inducing episodes of hypoglycemia.