Lupus strongly linked to imbalances in gut microbiome

According to a new study conducted by scientists at NYU School of Medicine, systemic lupus erythematosus (SLE) is linked to an abnormal mix of bacteria in the gut.

The disease is marked by the attack on joints, skin, and kidneys by the body's immune system.

The authors of the current study say their experiments are the first detailed evidence of a link between bacterial imbalances in the gut and potentially life-threatening forms of SLE.

The new study, published today in the Annals of Rheumatic Diseases online showed that 61 women diagnosed with SLE had roughly five times more gut bacteria known as Ruminococcus gnavus, than 17 women of similar ages and racial backgrounds who did not have the disease and were healthy. Lupus is more common in women than in men.

Study results further showed that disease "flares," which can range from instances of skin rash and joint pain to severe kidney dysfunction requiring dialysis, closely tracked major increases in R. gnavus bacterial growth in the gut, alongside the presence in blood samples of immune proteins called antibodies, specifically shaped to attach to the bacteria.

Study participants with kidney flares had especially high levels of antibodies to R. gnavus.

Senior study author Gregg Silverman said, "Our study strongly suggests that in some patients bacterial imbalances may be driving lupus and its associated disease flares," adding, "Our results also point to leakages of bacteria from the gut as a possible immune system trigger of the disease, and suggest that the internal gut environment may therefore play a more critical role than genetics in renal flares of this all too often fatal disease." He also suspects that antibodies to R. gnavus provoke a "continuous and unrelenting" immune attack on organs involved in flares.

Silverman added that the study could prompt the development of relatively simple blood tests to detect antibodies to leaked bacteria, which in turn could also be used to diagnose and track lupus progression and therapy, even in the disease's earliest stages.

Silverman, however, cautions that larger studies are needed to confirm how these bacteria may cause lupus. But if future experiments show similarly positive results, then it could result in shifts from current approaches to treating the disease, which focus on immune-suppressing anticancer medications to relieve symptoms and injury to the kidneys.