Lupus Microbiome May Drive Disease Activity Save

Silverman and colleagues have published their study of the fecal microbiome of systemic lupus erythematosus (SLE) patients and 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.

They studied 61 women diagnosed with SLE and 17 age-matched controls without lupus. They assessed microbiota for candidate pathobionts using fecal 16 S rRNA analyses along with sera profiled for antibacterial and autoantibody responses, and clinical activity measures. 

The found an overall 5-fold greater representation of Ruminococcus gnavus (RG) of the Lachnospiraceae family.

Notably, disease "flares" correlated with major increases in R. gnavus bacterial growth in the gut, as anti-RG antibodies correlated directly with SLEDAI score and anti-native DNA levels, and inversely with C3 and C4 levels.

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.