Genetic polymorphism and numerous clinical factors could influence tacrolimus pharmacokinetics, which led to large inter-and intra-individual variability.Since its narrow therapeutic range,predicting therapeutic outcome and individualized dosage remains to be a challenge. The study's objective is to identify the genetic and clinical factors that can influence clinical outcome in liver transplant.

A great number of studies had found significant correlation between tacrolimus pharmacokinetics and gene polymorphism. However, previous studies on the correlation between genetic factors and clinical outcome were controversial. Furthermore, most studies focused on single genetic polymorphism and clinical outcome, and very limited studies took multiple genetic factors and clinical factors into account.

This is a retrospective study. Eligible patients were those who had signed informed consent for genetic study in previous research projects ( IRB approval number：201512005RINC and 201612023RIND ). The present study will collect laboratory data, concurrent medications, and therapeutic drug monitoring (TDM) data. Patient survival, graft survival, acute rejection and tacrolimus-associated adverse events will be assessed.

Eligible patients were those who had signed informed consent for genetic study in our previous research projects.

Inclusion Criteria of the Previous Study:

• patients who underwent living-donor liver transplantation during January 2008 to December 2017
• at the age of 20-65
• with tacrolimus-based immunosuppression after liver transplant for at least 6 months.

Exclusion Criteria of the Previous Study :

• retransplantation
• multi-organ transplantation
• human immunodeficiency virus (HIV) positive.

Patients who underwent living donor liver transplantation (LDLT) during 2008 to 2017 in National Taiwan University Hospital and received tacrolimus-based immunosuppression.