Autoimmune diseases, such as lupus, may be caused by bacteria in the small intestines that travel to other parts of the body, a new study from Yale has revealed. The study also found that these diseases can be suppressed or even prevented with an antibiotic or vaccine specifically designed to destroy these bacteria.
Researchers analyzed Enterococcus gallinarum, a type of bacteria that typically lives in the gut but has also been found in other areas of the body. Using mice, the team observed how the presence of E. gallinarum in organs outside the gut led to inflammation and antibody production. The team then repeated this on human models by taking tissue samples from the livers of healthy volunteers and contaminating them with E. gallinarum. The same autoimmune response was observed.
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To prevent this autoimmune response, researchers created both a vaccine and an antibiotic to target E. gallinarum. Vaccines work by prompting the immune system to respond against an invading pathogen so that, in future attacks, the body will be prepared to fight it off. Antibiotics work by interfering with bacteria's ability to reproduce, therefore killing off the infection before it has time to become too dangerous. Results revealed that both the vaccine and the antibiotic reduced E. gallinarum's effect on mice's immune systems.
At the time, the researchers couldn't confirm how the bacteria travel from the gut to other organs in patients with autoimmune diseases, but they suspect an impaired gut barrier may be to blame. Dr. Martin Kriegel, the senior study author, suspects that the bacteria may travel from the gut to other parts of the body, such as the lymph nodes, after entering the bloodstream via this impaired barrier.
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"We found signs of an impaired gut barrier in patients and detected DNA of the same bacterium as found in mice within the liver tissue of these autoimmune patients," Kriegel, an adjunct assistant professor at the Yale School of Medicine at the time of this study, told Newsweek.
The results are exciting, but the team was able to suppress the autoimmune response only in mice. However, Kriegel told Newsweek that he was able to show that E. gallinarum induces the same stimulatory pathways in human liver cells in culture dishes. The team is working to develop a standardized testing for this bacterium and others also associated with chronic diseases.
"The goal is to gain enough knowledge to identify the right patient groups that may someday benefit from eradicating this bacterium," said Kriegel.
Autoimmune disease means the immune system attacks its own body. According to the Centers for Disease Control and Prevention, these diseases affect about 8 percent of the U.S. population, 78 percent of which are women.
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