Bacteria in the Gut May be a Cause of Lupus

NEW YORK, Feb. 19, 2019 /PRNewswire/ -- Pieces of bacteria that escape from the intestines may trigger lupus and associated disease flares in some patients, according to a new study partly funded by the Lupus Research Alliance. These findings may allow disease treatment with probiotics or diets that alter the mix of bacterial species in the intestines.

The thousands of bacterial species that live in our intestines affect our health in many ways, often for the good. The balance of species is misaligned in people with some autoimmune diseases, such as inflammatory bowel disease and rheumatoid arthritis, suggesting that certain combinations of bacteria may promote these diseases. Scientists weren't sure whether similar changes occur in patients with lupus.

To find out, Gregg Silverman, MD, of the NYU School of Medicine in New York, NY, and colleagues studied the bacteria in stool samples from 61 women with lupus and 17 women who didn't have the disease.  They discovered that the patients with lupus harbored fewer bacterial species overall. But one species, known as Ruminococcus gnavus, was five times more plentiful in patients with lupus. And the bacterium was particularly numerous in patients who were undergoing flares or who had kidney disease.

Patients with lupus produce immune system proteins known as antibodies that attack their own DNA. Dr. Silverman and his team found that these antibodies also target Ruminococcus gnavus. They also determined that the intestines of patients with lupus were leakier, which could allow bacteria or fragments of them to escape into the body. Once that has occurred, the immune system may respond by producing antibodies that mistake the patient's own DNA for molecules made by the bacteria. These antibodies would then attack organs such as the kidneys.

"These results are very exciting for the lupus community," commented Dr. Teodora Staeva, Research Director at the Lupus Research Alliance. "We are pleased to have recognized the potential of Dr. Silverman's work and provided grant funding to allow him and his team to pursue their hypothesis."

Researchers still need to confirm that the bacteria cause the symptoms of lupus. But if they do, the discovery could have a major impact on lupus treatment. Changing patients' diets or providing them with probiotics might reduce the numbers of Ruminococcus gnavus or boost the abundance of helpful bacterial species. Silverman and colleagues report their findings this week in Annals of Rheumatic Diseases.

About Lupus

Lupus is a chronic, complex autoimmune disease that affects millions of people worldwide. More than 90% of people with lupus are women; lupus most often strikes during the childbearing years of 15-45. African Americans, Latin Americans, Asians and Native Americans are two to three times at greater risk than Caucasians. In lupus, the immune system, which is designed to protect against infection, creates antibodies that can attack any part of the body including the kidneys, brain, heart, lungs, blood, skin, and joints.

About the Lupus Research Alliance

The Lupus Research Alliance aims to transform treatment while advancing toward a cure by funding the most innovative lupus research in the world. The organization's stringent peer review grant process fosters diverse scientific talent who are driving discovery toward better diagnostics, improved treatments and ultimately a cure for lupus.  Because the Lupus Research Alliance's Board of Directors fund all administrative and fundraising costs, 100% of all donations goes to support lupus research programs.

SOURCE Lupus Research Alliance