A systematic review and meta-analysis published in Frontiers in Microbiology has found that people with primary biliary cholangitis (PBC) have significant changes in the composition and diversity of their gut microbiota. Researchers say the paper adds to growing evidence that disruptions in the gut microbiome may play a role in the autoimmune liver disease.
The study analyzed data from 10 observational studies involving 1,057 participants, including 607 people with PBC and 450 healthy controls. Researchers combined findings from studies published between 2016 and 2025 to identify consistent patterns in the gut microbiome of people with the disease.
The analysis found that people with PBC had significantly lower microbial diversity than those without the disease. Most of the included studies also reported clear differences in the overall composition of the gut microbiota between patients and healthy controls.
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At the bacterial level, the researchers identified recurring shifts in specific groups of microbes. Neisseria, Klebsiella, Veillonella, Streptococcus, Enterococcus and Escherichia were consistently more abundant in people with PBC, while beneficial bacteria such as Bacteroides, Faecalibacterium, Blautia, Roseburia and Coprococcus were generally depleted. Many of the reduced bacteria are known to produce short-chain fatty acids that help maintain intestinal barrier function and regulate immune responses.
The researchers suggest that these microbial changes could contribute to disease development by disrupting the gut-liver axis, promoting inflammation, altering bile acid metabolism and impairing immune regulation. However, they emphasized that the findings do not establish a causal relationship between gut microbiota changes and PBC.
The authors noted important limitations, including that most of the studies were observational and conducted in China or Japan, with limited information from other regions and considerable variation in study design.
“Further longitudinal and functional studies are needed to clarify causality and mechanisms and to support the development of microbiota-based precision therapies for PBC,” they concluded.
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