In particular, the hematopoietic cell lineage, Toll-like receptor signaling pathway, graft-versus–host disease, and PPAR signaling pathway were not significantly enriched in pathways related to differentially transcribed liver genes between patients with ALD, HBV, HCV, HCV cirrhosis, NASH and their HCs, indicating that these four pathways may be involved in the mechanism by which the gut microbiota affects PBC (Table 1). This evidence concerns the gene PPARA and Cirrhosis.