Donor and recipient P450 gene polymorphisms influence individual pharmacological effects of tacrolimus in Chinese liver transplantation patients

The immunosuppressant drug tacrolimus (Tac) used for the prevention of immunological rejection is a metabolic substrate of cytochrome P450 enzymes. This study was designed to evaluate the short-term and long-term potential influence of single-nucleotide polymorphisms (SNPs) in CYP450 genes of liver transplant (LT) recipients as well as the donors on individual pharmacological effects of Tac and to guide individualized-medication from the perspective of pharmacogenomics. Twenty-one SNPs of the CYP450 gene were genotyped for both recipients and donors in 373 LT patients receiving Tac-based immunosuppressants. The Tac concentration/dosage ratio (C/D) was evaluated from the initial medication until one year after LT. The C/D ratio was significantly higher when the donor and/or recipient genotype of CYP3A5 rs776746 was G/G or rs15524 was T/T or rs4646450 was C/C all through one year after transplantation. Comparing the effect of donor gene variants of rs776746, rs15524, and rs4646450 on Tac C/D ratios with the recipients, statistically significant differences were found between the donor T/T group and the recipient T/T group in rs15524 at 1 month and 6 months, and at 6 months, the donor C/C group differed from the recipient C/C group in rs4646450. In conclusion, rs776746, rs15524, and rs4646450 of CYP3A5 had a significant influence on Tac pharmacological effects for both the initial use and long-term use. The donor liver genotype and the recipient intestine genotype contribute almost equally in the short-term, but the donor genotype had a greater effect than the recipient genotype at 6 months. Personalized Tac treatment after LT should be based on the CYP3A5 genotype.