How gut bacteria may be linked to lupus

Bacteria and other microorganisms living in your gut, known as the microbiome, play a big role in keeping you healthy.

They help you digest food, provide essential vitamins and other nutrients, and help control your immune system.

But when the intestinal communities are out of balance, they may contribute to health problems, including autoimmune diseases such as inflammatory bowel disease, type 1 diabetes, multiple sclerosis, and rheumatoid arthritis.

A new study in women now suggests that systemic lupus erythematosus, also known as lupus or SLE, is linked to the overgrowth of certain bacteria in the intestines.

Lupus is a chronic disease that results in inflammation in many parts of the body, including the kidneys, heart, and brain. This disease, which is more common in women, is potentially life-threatening.

Like other autoimmune diseases, lupus is caused by the immune system mistakenly attacking a person’s own tissues, rather than foreign germs.

Bacteria overgrowth tied to lupus

In the study, researchers found that 61 women diagnosed with lupus had higher amounts of a gut bacterium known as Ruminococcus gnavus, compared to 17 healthy women.

The bacterium was also present in healthy women, but at much lower levels.

“The results showed that lupus patients have gut microbiome patterns different from healthy individuals, and these changes correlated with disease activity,” said Jessy Alexander, PhD, a research professor in the department of medicine at the University at Buffalo, who was not involved in the study.

The paper was published February 19 in the Annals of the Rheumatic Diseases.

Most people with lupus have times when their disease is mostly quiet, known as a remission. In between, symptoms can increase, or “flare.”

The study found that R. gnavus levels increased in the gut during flares. Blood tests also showed a rise in antibodies — immune proteins — that bind to the bacterium during these times.

Alexander said “the antibodies generated by the patient against this bacteria was directly proportional to the severity of the disease.”

The authors of the paper caution that their results can’t show whether the overgrowth of R. gnavus causes or triggers lupus, or if disease flares allow the bacterium to thrive in the gut.

Dr. Martin Kriegel, PhD, an assistant professor of immunobiology and rheumatology at Yale School of Medicine, who was not involved in the study, said it’s likely a “two-way street.”

Alexander said the study strengthens the idea “that gut bacteria affect the disease lupus, and opens the door to developing prognostic tests that reveal the disease status of the lupus nephritis patient.”

“However, a lot more work remains to be done,” she added.

Source: healthline.com

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