Beyond the microbiome: unraveling gut dysbiosis and its impact on systemic lupus erythematosus

Background Systemic lupus erythematosus (SLE) is an autoimmune disease influenced by genetic and environmental factors, with gut microbiota (GM) changes emerging as a key environmental contributor.Methods A total of 42SLE patients and 30 age – and sex-matched healthy controls were enrolled. Stool samples from all participants were analyzed using quantitative SYBR Green Real-Time PCR to detect and quantify selected bacterial taxa at phylogenetic and species levels.Results Our results highlight the signature mark of SLE gut dysbiosis, namely decreased species richness and diversity with a reduction in the Firmicutes to Bacteroidetes (F/B) ratio. Specific reductions were observed in Prevotella, Ruminococcus, Lactobacillus (including Lactobacillus reuteri), Bifidobacterium, Akkermansia muciniphila, and Faecalibacterium prausnitzii. Conversely, proinflammatory Bacteroidetes and Bacteroides were significantly increased. Notably, SLE patients receiving Mycophenolate mofetil (MMF) displayed a significantly higher F/B ratio than non-MMF users.Conclusions This study reinforces the link between gut dysbiosis and SLE, highlights conflicting evidence regarding the role of Lactobacillus in SLE, and highlights a possible new mechanism through which MMF impacts SLE. We recommend future research focus on species-level analysis to clarify contradictory results.