Patients and Sample collection
All the liver transplantation recipients included in this study met the
following criteria: age > 18 years, postoperative survival
time ≥ 3 months, normal liver function within 1 month following surgery,
and patients having received treatment with tacrolimus in combination
with steroids and mycophenolate mofelil after transplantation. The
corresponding donors met the following criteria: hepatitis or other
infectious disease free, normal liver and kidney function, and no
treatment with any drug known to interact with tacrolimus within the two
previous weeks.
Tacrolimus was administered orally at a dose of 0.05 mg/kg/d twice daily
from the first day following transplantation. Routine therapeutic drug
monitoring (TDM) for tacrolimus was initiated 48 h after the
administration of its first dose. The initial tacrolimus concentration
(C0) in whole blood was determined through an enzyme
amplification immunoassay using the EMIT 2000 tacrolimus assay kit
(Siemens Healthcare Diagnostics, DE, USA) on the day of blood
collection. The tacrolimus C0/D ratio was calculated by
dividing the tacrolimus concentration by the corresponding
weight-adjusted dose. Liver samples of the included donors were
collected during liver trimming at the time of transplantation, cut into
small pieces, and immediately stored in liquid nitrogen.