A recent study exploring the fecal microbiome of systemic lupus erythematosus (SLE) patients found roughly five times more gut bacteria known as Ruminococcus gnavus, and that these abnormalities in microbiota can correlate with measures of disease severity in SLE.
The researchers studied 61 women diagnosed with SLE and 17 age-matched controls without lupus, assessing microbiota for candidate pathobionts using fecal 16 S rRNA analyses along with sera profiled for antibacterial and autoantibody responses, and clinical activity measures.
The authors found an overall 5-fold greater representation of R. gnavus of the Lachnospiraceae family.
Notably, disease “flares” correlated with major increases in R. gnavus bacterial growth in the gut, as anti-R. gnavus antibodies correlated directly with SLEDAI score and anti-native DNA levels, and inversely with C3 and C4 levels.
The highest levels of serum anti-RG strain-restricted antibodies were detected in those with active nephritis (including Class III and IV) in the discovery cohort, with findings validated in two independent cohorts.
These findings suggest a specific strain of a gut commensals may contribute to the immune pathogenesis of lupus nephritis.
Jack Cush, MD, is the director of clinical rheumatology at the Baylor Research Institute and a professor of medicine and rheumatology at Baylor University Medical Center in Dallas. He is the executive editor of RheumNow.com. A version of this article first appeared on RheumNow, a news, information and commentary site dedicated to the field of rheumatology. Register to receive their free rheumatology newsletter.