A Randomised Clinical Trial Assessing the Efficacy and Safety of Mycophenolate Mofetil Versus Azathioprine for Induction of Remission in Treatment Primary Biliary Cholangitis-Autoimmune Hepatitis Overlap Syndrome

Inclusion Criteria: 1. Patients aged 18-70 years; 2. Diagnosed with PBC-AIH overlap syndrome according to Paris criteria; 3. Agreed to participate in the trial, and assigned informed consent; 4. The WBC count ≥2.5x10\^9/L and platelet count ≥50x10\^9/L. Exclusion Criteria: 1. The presence of hepatitis A, B, C, D, or E virus infection; 2. Patients with presence of serious decompensated cirrhosis; 3. Patients have a history of glucocorticoid or immunosuppressant medication before enrollment; 4. Liver damage caused by other reasons: such as primary sclerosing cholangitis, non-alcoholic steatohepatitis, drug induced liver disease or Wilson disease. 5. Pregnant and breeding women; 6. Severe disorders of other vital organs, such as severe heart failure, cancer; 7. Parenteral administration of blood or blood products within 6 months before screening; 8. Recent treatment with drugs having known liver toxicity; 9. Taken part in other clinic trials within 6 months before enrollment.