Oral Microbial Dysbiosis and Pathogenic Functional Shifts in Mucosa-dominant Pemphigus Vulgaris and Low-risk Mucous Membrane Pemphigoid

This pioneering study characterizes the distinct oral microbial dysbiosis patterns in mucosa-dominant pemphigus vulgaris (MD-PV) and low-risk mucous membrane pemphigoid (LR-MMP), two autoimmune bullous diseases with significant oral morbidity. Through 16S rRNA sequencing of saliva samples from patients and healthy controls, the research revealed disease-specific signatures: MD-PV exhibited pronounced enrichment of Firmicutes (particularly Bacilli), while LR-MMP showed enrichment of Coriobacteriia coupled with depletion of Proteobacteria. Critically, both diseases shared conserved functional alterations, including microbial upregulation of oxidative stress response pathways and UMP biosynthesis II, suggesting a common mechanism exacerbating mucosal damage. MD-PV further demonstrated a unique phenotypic shift toward facultative anaerobes and Gram-positive bacteria. These findings establish novel microbial biomarkers for each condition and uncover shared pathogenic pathways rooted in microbiome-driven oxidative stress, advancing our understanding of host-microbe interactions in bullous disorders and informing future therapeutic strategies.