Abstract: Objective The serum biochemical indexes, autoantibodies and liver histopathological manifestations of patients with autoimmune hepatitis (AIH)- primary biliary cholangitis (PBC) overlap syndrome were recorded, and the clinical pathological characteristics of these patients were analyzed. Methods From June 2016 to June 2019, 78 clinically diagnosed autoimmune liver disease (AILD) patients in our department were selected, including 32 AIH patients (AIH group), 24 PBC patients (PBC group)and 22 patients with AIH-PBC overlap syndrome (AIH-PBC group). The measurement data are expressed as (±s) and the comparison between groups is analyzed by t test. Counting data are expressed as percentages, and chi-square test is used for comparison between groups. Results ALP in AIH-PBC group [(412.4±226.4) U/L] was significantly higher than that in AIH group [(108.2±68.1) U/L](P<0.05). GGT in AIH-PBC group [(430.5±152.8) U/L] was significantly higher than that in AIH group [(118.7±65.2) U/L] (P<0.05). IgM in AIH-PBC group [(5.2±1.7) g/L] was significantly higher than that in AIH group [(2.5±0.8) g/L](P<0.05). ALT in AIH-PBC group [(182.6±68.1) U/L] was significantly higher than that in PBC group [(98.7±45.7) U/L]. AST in AIH-PBC group [(174.9±70.2) U/L] was significantly higher than that in PBC group [(104.6±52.4) U/L]; IgG in AIH-PBC group [(19.5±6.6) g/L] was significantly higher than that in PBC group [(15.2±1.9) g/L]. AMA expression in patients in AIH-PBC group(72.7%) was significantly higher than that in AIH group (0%) (P<0.05). The expression of AMA M2 in patients (100%) in AIH-PBC group (100%) was significantly higher than that in AIH group (0%) (P<0.05). SMA expression in AIH-PBC group (72.7%) was significantly higher than that in PBC group (16.7%)(P<0.05). ANA expression in patients (90.9%) in AIH-PBC group was significantly higher than that in PBC group (12.5%) (P<0.05). Conclusion Serum biochemical indexes, autoantibodies and liver biopsy pathological manifestations of patients in AIH-PBC group have the characteristics of AIH and PBC diseases, while the differences in serum biochemical indexes and autoantibody detection levels can be used as the basis for distinguishing AIH-PBC overlap syndrome.

Key words: Autoimmune liver diseases, Auto-immune hepatitis, Primary sclerosing cholangitis, Antinuclear antibody, Anti-smooth muscle antibody