Microbial Modulation of the Gut–Liver Axis in Autoimmune Liver Diseases

Autoimmune liver diseases (AILDs), including autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis, are chronic inflammatory conditions influenced by complex interactions among genetic, environmental, and immunological factors. Recent studies have highlighted the critical role of the gut microbiota in regulating immune responses beyond the gastrointestinal tract via the gut-liver axis. This review examines the interactions between intestinal microecology and AILDs, with a focus on mechanisms such as bacterial translocation, disruption of the intestinal barrier, and modulation of microbial metabolites. Dysbiosis, involving alterations in both bacterial and fungal communities, has been associated with immune dysregulation and hepatic inflammation. Evidence indicates that short-chain fatty acids, bile acids, and microbial products such as lipopolysaccharides influence hepatic immune tolerance and inflammatory signaling pathways. Several diagnostic and therapeutic approaches, including probiotics, fecal microbiota transplantation, and bile acid regulation, have shown potential to slow or alter disease progression. However, the clinical translation of these findings remains limited due to interindividual variability and the complex nature of the gut-liver axis. Continued research is needed to develop precision medicine strategies that can harness intestinal microecology for improved management of AILDs.