The gut microbiome and its metabolomic potential in primary Sjögren syndrome (pSS) remain largely unexplored. Here, we perform whole-metagenome shotgun sequencing of fecal samples from 206 pSS patients and 355 non-pSS controls, integrating compositional and functional profiling with serum and fecal metabolomes. pSS is associated with extensive multi-kingdom alterations, including 49 bacterial (e.g., Streptococcus parasanguinis, Ligilactobacillus salivarius, and Veillonella parvula), 19 fungal (notably Candida albicans), and 1,323 viral species. These signatures form robust inter-kingdom correlations and achieve high diagnostic accuracy in an independent validation cohort. Functional and metabolomic analyses reveal enrichment of toxin-related and aromatic pathways and depletion of protective metabolites in patients. pSS-enriched bacteria harbor abundant immunogenic epitopes, virulence factors, and antimicrobial resistance genes, and induce proinflammatory responses ex vivo. Together, these findings outline a multi-faceted microbial framework for pSS and suggest mechanistic links between gut dysbiosis and immune dysregulation.
Chen et al. (Fri,) studied this question.