The Role of Intestinal Microbiota and Immune System Interactions in Autoimmune Diseases.

Background: The intricate interplay between the intestinal microbiota and the immune system has emerged as a central theme in understanding autoimmune disease pathogenesis. This review comprehensively explores the role of gut microbiota in shaping immune development, establishing immune tolerance, and contributing to both local and systemic immune regulation. Methods: This review synthesizes the modulatory effects of microbial metabolites (eg, short-chain fatty acids and indole derivatives) on regulatory T cells (Tregs) and inflammatory pathways. The concept of "dysbiosis" is examined from functional and compositional perspectives, linking microbial imbalances to autoimmune disorders (IBD, MS, RA, and T1D). Microbiota-targeted therapeutic interventions (probiotics, prebiotics, FMT) are also evaluated. Key Findings: The synthesis of the literature confirms that microbial metabolites have a direct impact on Treg differentiation and inflammatory pathways. Dysbiosis, through functional and compositional disruptions, is strongly associated with the pathogenesis of various autoimmune disorders, including Inflammatory Bowel Disease, Multiple Sclerosis, Rheumatoid Arthritis, and Type 1 Diabetes. Therapeutic interventions such as probiotics, prebiotics, and Fecal Microbiota Transplantation show promising potential in restoring microbial and immune homeostasis. Conclusion: This review highlights the role of the gut-immune axis in autoimmune diseases. Despite current challenges, such as individual variability and determining causality, future directions toward precision microbiota and immune modulation are promising. This study provides a robust foundation for researchers and clinicians seeking to understand and therapeutically target the gut-immune axis.