A clue on the connection between the microbiome and autoimmune disease

Lab Chat: How migrating gut bacteria might do damage

SMALL INTESTINES STUDDED WITH E. GALLINARUM BACTERIA. (MANFREDO VIEIRA ET AL., SCIENCE 2018)

Scientists have discovered a particular microbe that can venture out of the gut and set up shop in other organs, where it seems to trigger an autoimmune response that's similar to what's seen in patients with lupus. The finding gives researchers new clues about the potential link between the microbiome and autoimmune disease. Here's what Dr. Martin Kriegel of Yale told me about the work, published in Science.

What did you discover about a potential link between the microbiome and lupus?

Studies have suggested autoimmune disease might have a microbial trigger. We gave mice that modeled autoimmune disease broad spectrum antibiotics to manipulate the microbes in the gut. We almost completely prevented mortality. But a big hurdle is figuring out which bacteria are behind the link, and how. So we tracked the bacteria with fluorescent tags.

What did you see?

We saw that E. Gallinarum bacteria somehow crossed the barrier of the gut and impacted immune cells. The bacteria tipped the balance from being prone to developing autoimmune disease to actually developing it. When we went to human liver tissue, we also found these microbes. We think it drives important autoimmune pathways.

Journal article:

Translocation of a gut pathobiont drives autoimmunity in mice and humans