The Gut-Lupus Link: How Gut Bacteria May Impact Disease Development and Activity
New research findings offer interesting insights around the potential gut-lupus connection. The study’s results indicate people with lupus have reduced species diversity in their guts, meaning they have fewer types or strains of bacteria than those without lupus. In fact, the study’s subjects with higher disease activity (more severe or frequent flares) had the fewest types of bacteria species present.
Additionally, the study participants with lupus had five times the amount of one specific strain of bacteria: Ruminococcus gnavus (RG). While RG is not a “bad” species of bacteria per se, the researchers found that a particularly high concentration of any bacteria strain increases risk of flares in people with lupus. Not only do people with lupus seem to have reduced bacterial diversity in general and high levels of RG bacteria in particular, those with active lupus nephritis (LN) exhibited the strongest antibody response to RG and a certain RG-produced molecule known as lipoglycan.
Although lipoglycan does not typically cause illness when it is kept safely inside the intestinal tract, the researchers suggest that people with LN may have a leaky gut, which allows the lipoglycan to filter outside of the intestines and possibly result in an autoantibody response liked to the development of kidney disease. The findings suggest that microbiome testing and treatments that help shift microbiome diversity may be beneficial for people with lupus. More research is needed to fully understand the relationship between gut bacteria, lupus and LN.
The Lupus Foundation of America (LFA) has supported gut-lupus research through several research grants. Diane Kamen, MD, MSCR, a member of the LFA’s Medical-Scientific Advisory Council and recipient of the LFA-funded Lifeline Grant for her study, “Impact of the Gut Metagenome on Autoimmunity,” comments, “Given the complex relationship between the microbiome and immune system, it is exciting to see research into links between lupus and the microbiome expanding, involving experts from multiple disciplines across many lupus centers. It is such a promising area of research with the potential to lead to safe interventions for people with lupus or at risk of lupus.”
Kamen also received funding from the National Institutes of Health to continue her work from 2016 through 2021 and will be presenting at the upcoming American College of Rheumatology meeting in Atlanta. Learn more about her recent research and continue to follow the LFA for further developments.