Abstract: Objective The clinical feature and biochemical response to immunosuppressive therapy were compared between patients with primary biliary cholangitis (PBC) and PBC-autoimmune hepatitis (AIH)overlap syndrome (OS). Methods 64 patients with PBC and 27 patients with PBC-AIH OS were encountered in our hospital between May 2017 and February 2023, and all undergone liver biopsies. The patients in the two groups were treated by ursodeoxycholic acid (UDCA) or UDCA and prednisone combination, and response were assessed by one year. Results Serum AST, globulin and IgG levels in patients with PBC-AIH OS were 103.5(74.5, 213.3)U/L, 34.2±7.3g/L and 19.1±8.1g/L, all significantly higher than [71.0(32.0, 119.0)U/L,30.2±6.2g/L and 14.7±5.3g/L, respectively, P<0.05] in patients with PBC; histo-patholocially, hepatic activity index, fibrosis staging, interfacial inflammation, fusion necrosis and portal inflammation in patients with PBC-AIH OS were much more severe than in those with PBC(P<0.05); by one year, complete, partial and non-biochemical response were 56.3%, 26.7% and 17.2% in 64 patients with PBC, while they were 44.4%, 37.0% and 18.5% in 27 patients with PBC-AIH OS. Conclusion PBC and PBC-AIH OS predominantly involve in middle-aged and elderly women, and there is little discrepancy in clinical manifestations and characteristic serum autoimmune antibodies between the two groups, while the intrahepatic histo-pathologic damage were obviously severe in patients with PBC-AIH OS, with relatively poor response rate to immunosuppressive therapy, which warrants close surveillance in clinical practice.

Key words: Autoimmune liver disease, Primary biliary cholangitis, Overlap syndrome, Clinical features, Response