Sept. 5, 2018
Our microbiome includes all of the trillions of microorganisms that live in and on us. A recent review article about key discoveries on the role of the microbiome in lupus includes two researchers funded by the Lupus Research Alliance who may have discovered how some of these microbial passengers promote lupus by spurring the immune system to attack the body’s own tissues.
Lupus Research Alliance grant recipient Gregg Silverman, MD of the NYU School of Medicine and his team have uncovered evidence that certain microbes from our intestines (gut micriobiota) may help trigger lupus nephritis, the kidney inflammation that affects about half of patients with lupus. The researchers thought that lupus might result when the immune system mistakes molecules from patients’ cells for molecules released by bacteria. But they weren’t sure which bacteria were producing these molecules. The scientists discovered that the likely culprits are specific types of bacteria in the Lachnospiraceae family that live in the human intestines. These bacteria were five times more likely to occur in patients with lupus than in people who don’t have the disease. Patients with active lupus nephritis produced increased amounts of immune system proteins that target these microbes. Dr. Silverman and his team suspect that the immune system’s efforts to battle these bacteria may also cause damage to the kidneys.
With their Novel Research Grant from the Lupus Research Alliance, Martin Alexander Kriegel, MD, PhD, and colleagues at the Yale University School of Medicine found that another type of bacterium might promote lupus when it leaves the intestine and moves to other parts of the body. The team determined that mice developed signs of lupus if the bacteria settled in their liver and lymph nodes. The animals improved after treatment with antibiotics that kill the bacterium. The scientists also detected the bacterium in liver samples from patients with lupus but not in people who didn’t have the disease.
Both Lupus Research Alliance-funded studies suggest that modifying patients’ microbiomes might be a strategy for treating lupus symptoms or preventing the disease. These studies, along with other discoveries about the human microbiome, are providing a better understanding of the roles microorganisms play in lupus.