Distinct gut microbiome profiles in Korean systemic lupus erythematosus patients.

BACKGROUND: Systemic lupus erythematosus (SLE) is an autoimmune disease associated with systemic inflammation and multi-organ involvement. Emerging evidence suggests that gut microbiota dysbiosis may contribute to its immunopathogenesis. OBJECTIVE: This study aimed to characterize gut microbial composition and diversity in Korean SLE patients and evaluate associations with clinical features. METHODS: Fecal samples from 157 SLE patients and 50 healthy controls (HC) were analyzed using 16S rRNA gene sequencing. Alpha and beta diversity metrics were assessed, and taxonomic differences were analyzed. Subgroup comparisons were conducted based on lupus nephritis (LN) status and disease activity. Functional predictions were inferred using PICRUSt2. RESULTS: SLE patients exhibited significantly reduced microbial richness (Chao1, ACE, Fisher indices), while evenness (Shannon, Simpson) was preserved. Beta diversity analysis revealed distinct clustering between SLE and HC groups. SLE was characterized by enrichment of Bacteroides, Streptococcus, and Veillonella, and depletion of Collinsella, Ruminococcus, and Bifidobacterium. LEfSe identified several discriminatory taxa. However, no significant microbial differences were observed between LN-positive and LN-negative groups or between high and low disease activity groups. Functional prediction revealed minimal differences in microbial pathways between groups. CONCLUSION: These findings highlight distinct gut microbial alterations in Korean SLE patients and support the potential utility of microbiome profiles as diagnostic biomarkers or therapeutics.