Gut microbiota alterations in primary biliary cholangitis: a systematic review and meta-analysis

Area of Science:

• Gastroenterology and Hepatology
• Microbiome Research
• Immunology

Background:

• Primary biliary cholangitis (PBC) is a chronic autoimmune liver disease where gut microbiota dysbiosis is increasingly implicated in its pathogenesis.
• Previous studies on gut microbiota in PBC are limited by small sample sizes and inconsistent methodologies, necessitating a quantitative synthesis.

Purpose of the Study:

• To systematically review and perform a meta-analysis evaluating gut microbiota alterations in patients with primary biliary cholangitis (PBC).

Main Methods:

• A comprehensive search of PubMed, Web of Science, Embase, and Cochrane Library was conducted up to January 23, 2026.
• Meta-analyses of alpha-diversity indices, beta diversity, and taxonomic alterations were performed using standardized mean differences (SMDs) and 95% confidence intervals (CIs).
• Sensitivity, subgroup, and meta-regression analyses were employed to investigate heterogeneity.

Main Results:

• Ten studies with 1,057 participants (607 PBC patients, 450 controls) were included.
• PBC patients exhibited significantly reduced alpha diversity (lower Shannon and Chao1 indices, fewer OTUs) and altered beta diversity compared to controls.
• Specific bacterial taxa were enriched (e.g., Neisseria, Klebsiella) or depleted (e.g., Bacteroides, Faecalibacterium) in PBC patients.

Conclusions:

• Primary biliary cholangitis is associated with significant gut microbiota alterations, including reduced diversity and taxonomic shifts.
• The findings highlight the potential role of gut microbiota in PBC, but longitudinal and functional studies are required to establish causality and explore clinical applications.