Gut microbiota and immune tolerance mechanisms in autoimmune diseases

Autoimmune diseases arise from a failure of immune tolerance, leading to chronic immune-mediated damage to self-tissues. Increasing evidence indicates that the gut microbiota plays a central role in shaping immune development, maintaining immune homeostasis, and regulating tolerance mechanisms. This review synthesizes current knowledge on the interactions between gut microbial communities and the host immune system in the context of autoimmune pathogenesis. Special emphasis is placed on regulatory T cell (Treg) induction, short-chain fatty acid (SCFA) signaling, intestinal barrier integrity, and antigen-presenting cell modulation as key mechanisms through which the microbiota maintains immune tolerance. Dysbiosis has been consistently associated with autoimmune conditions such as rheumatoid arthritis, type 1 diabetes, multiple sclerosis, and inflammatory bowel disease, suggesting that microbial imbalance contributes to disease onset and progression. Furthermore, emerging evidence highlights the therapeutic potential of microbiota-targeted interventions, including dietary modulation, probiotics, and defined microbial consortia, in restoring immune equilibrium. Integrating findings from immunology and microbiome research, this paper underscores the gut microbiota as a dynamic regulator of immune tolerance and a promising target for precision medicine approaches in autoimmune diseases. Understanding these mechanisms provides critical insights for developing novel diagnostic and therapeutic strategies aimed at preventing and managing immune-mediated disorders.