Targeting gut bacteria can treat autoimmune diseases: study

WASHINGTON, March 8 (Xinhua) -- Bacteria found in the small intestines of mice and humans can travel to other organs and trigger an autoimmune response, according to a new study published on Thursday in the journal Science.

The findings suggested promising new approaches for treating chronic autoimmune conditions, including systemic lupus and autoimmune liver disease, the researchers said.

The researchers at Yale University have found that the autoimmune reaction can be suppressed with an antibiotic or vaccine designed to target the bacteria.

They focused on Enterococcus gallinarum (E. gallinarum), a bacterium that is able to spontaneously "translocate" outside of the gut to lymph nodes, the liver and spleen.

In models of genetically susceptible mice, the researchers observed that in tissues outside the gut, E. gallinarum initiated the production of auto-antibodies and inflammation, hallmarks of the autoimmune response.

Scientists then confirmed the same mechanism of inflammation in cultured liver cells of healthy people, and the presence of this bacterium in livers of patients with autoimmune disease.

They also found that they could suppress autoimmunity in mice with an antibiotic or a vaccine aimed at E. gallinarum. With either approach, the researchers were able to suppress growth of the bacterium in the tissues and blunt its effects on the immune system.

"The vaccine against E. gallinarum was a specific approach, as vaccinations against other bacteria we investigated did not prevent mortality and autoimmunity," said the paper's senior author Martin Kriegel.

The vaccine was delivered through an injection in the muscle to avoid targeting other bacteria that reside in the gut, according to Kriegel.

"Treatment with an antibiotic and other approaches such as vaccination are promising ways to improve the lives of patients with autoimmune disease," he added. Enditem