Abstract: Objective To observe the regularity of cytochrome P450 (CYP) polymorphism in liver transplantation patients and its influence on the application of tacrolimus. Methods From April 2016 to March 2019, 146 patients who received liver transplantation in our hospital and survived for more than 1 month were selected and randomly divided into experimental group and control group. The patients in control group routinely detected FK506, biochemical indicators and observed its clinical characteristics. On the basis of the above items, the patients in experimental group were tested for CYP3A4*1B and CYP3A5*3 gene single nucleotide polymorphisms. Results There were no significant differences in the FK506 level, C0/D value, renal damage, acute rejection, infection and mortality between the experiment and the control group. Among the 73 recipients in the experiment group, CYP3A4*1B were all wild-type. CYP3A5*3 detection type: 35 patients were found A/G wild type (46.1%); 33 cases G/G mutant type (43.4) %; 5 cases A/A mutant type (6.6%). The C0/D value in G/G mutation patients was significantly higher than that of A/G wild-type and A/A mutant patients (P=0.002, 0.007 and 0.034 at 3, 6 and 12 months after surgery).There was no significant difference in FK506 level between groups. The incidence of infection in patients with G/G mutation in the experiment group was significantly higher than that in A/G wild-type patients (χ²=7.066, P=0.008). Conclusion The CYP3A4*3 genotype is mainly wild type in China, and it has little effect on FK506 metabolism. The genetic polymorphism of CYP3A5*3 is closely related to the metabolism of tacrolimus, and variant patients may need a lower dose of tacrolimus to reach the target level and reduce the incidence of infection.

Key words: Tacrolimus, Cytochrome P450, Genetic polymorphism, Liver transplantation