The Clinical Investigation On The Individualized Drug Therapy Of Tacrolimus In Renal Transplantation Recipients Based On The Polymorphism Of CYP3A5*3

Part IThe distribution of CYP3A5*3 genotypes in Chinese renal transplantation recipients detected by PyrosequencingTMObjective:To establish a pyrosequencing method to detect the CYP3A5*3 polymorphism, and to investigate the distribution of CYP3A5*3 genotypes in Chinese renal transplantation recipients, in order to provide a new technique that can simply, rapidly and accurately detect the CYP3A5*3 polymorphism in renal transplantation recipients.Materials and methods:Genomic DNA was extracted from 245 renal transplantation recipients pre-or post-transplantation and 200 health human blood cells and the CYP3A5*3 gene fragments were amplified by PCR. CYP3A5*3 polymorphism was detected on PyroMark ID by pyrosequencing technology. A Sanger method by Beckman coulter CEQ800 was used as a standard control. The reliability of pyrosequencing technology and the distribution of CYP3A5*3 polymorphism in renal transplant recipients were observed and analyzed.Results:A new method was established to detect the CYP3A5*3 polymorphism of renal transplantation recipients. The detection rate and repetition rate were 100% as it was confirmed by the repeated testing and Sanger sequencing standards control. The CYP3A5*3 distribution in renal transplantation recipients was:*1/*1 genotype in 23 cases (9.4%),*1/*3 in 101 cases (41.2%) and*3/*3 in 121 cases (49.4%). The CYP3A5*3 gene frequency of renal transplantation recipients was 70.0%. The CYP3A5*3 distribution in health control group was:*1/*1 genotype in 15 cases (7.5%),*1/*3 in 89 cases (44.5%) and*3/*3 in 96 cases (48.0%). The CYP3A5*3 gene frequency of health people was 70.3%.The genotype frequencies were not significantly difference between transplant recipients and health human group that predicted by the Hardy-Weinberg equilibrium.Conclusion:This pyrosequencing assay to detected the CYP3A5*3 polymorphism proved to be a simple, rapid, and accurate alternative to conventional methods, and it can be a preferred option in clinical application. The CYP3A5 expressers (CYP3A5*1/*1 genotype and CYP3A5*1/*3 genotype) were equivalent to the CYP3A5 nonexpressers (CYP3A5*3/*3 genotype), so it is necessary to detected the CYP3A5*3 polymorphism in renal recipients in order to help the personalized immunosuppressant therapy come true. Partâ…¡Impact of CYP3A5*3 polymorphism on the blood concentration and efficacy of tacrolimus in renal transplantation recipientsObjective:This study was to evaluate the application of pyrosequencing in detecting CYP3A5*3 polymorphisms of renal transplantation recipients and to investigate the impact of CYP3A5*3 polymorphism on the blood concentration and efficacy of tacrolimus in renal transplant recipients, to approach the significance of detecting CYP3A5*3 polymorphism in renal recipients that take tacrolimus as basic immunosuppressant, and to provide a fundament for individualized tacrolimus therapy in renal transplantation recipients based on CYP3A5*3 polymorphism.Materials and methods:Eighty-six renal recipients receiving tacrolimus as basic immunosuppressant were genotyped for CYP3A5*3 polymorphism by the pyrosequencing assays. Tacrolimus trough concentration of the patients was measured by enzyme multiplied immunoassay technique, and concentration/adjusted dose ratio (C/D) at 7d,14d, 1m,3m and 6m after renal transplantation was recorded as well as the rate of acute rejection(AR) and adverse effects in the first six months postoperation.Results:There were CYP3A5*1/*1 genotype in 12 cases (13.9%), *1/*3 in 30 cases (34.9%) and *3/*3 in 44 cases (51.2%) identified in 86 renal recipients. The concentration/adjusted dose ratios of CYP3A5 *1/*1 and*1/*3 patients were significantly lower than those of*3/*3 patients at the same time post-transplantation. The rate of AR was significant higher in the CYP3A5*1/*1 or*1/*3 patients. The rate of neurotoxicity and hyperglycaemia was little higher in the CYP3A5*3/*3 patients, but there was no statistical difference. There was no significant difference on the incidence of nephrotoxicity or other adverse effects between the CYP3A5 *1/*1 or*1/*3 patients and the CYP3A5*3/*3 patients.Conclusion:There was a significant impact of CYP3A5*3 polymorphism on the blood concentration of tacrolimus in renal transplantation recipients. CYP3A5*1 carriers required a higher dose of tacrolimus to reach target blood concentration compared with those with the CYP3A5 *3/*3 genotype. Evaluating the CYP3A5*3 polymorphism of the recipients prior to transplantation by the PyrosequencingTM assay may be helpful in determining an appropriate initial dosage or different CYP3A5*3 genotypes recipients, rapidly achieving adequate immunosuppression, and ultimately improving the outcome of renal transplantation.Partâ…¢The Clinical Investigation on the Individualized Drug Therapy of Tacrolimus in Renal Transplantation Recipients Based on the Polymorphism of CYP3A5*3Objective:The study was to explore the clinical benefit of CYP3A5*3 polymorphim on directing individualized tacrolimus therapy in renal transplantation recipients, and to discuss the optimal initial tacrolimus dosage in different CYP3A5*3 genotypes of Chinese renal transplantation recipients.Materials and methods:The CYP3A5*3 genotypes of renal recipients were detected by the PyrosequencingTM assay one or two weeks before the operation to determine the genetic metabolic type of CYP3A5 (CYP3A5 express:CYP3A5*1/*1 or CYP3A5*1/*3; nonexpress: CYP3A5*3/*3). Eighty-three patients were randomized divided into two groups:the study group and the control group. The patients in the study group were received tacrolimus at an initial dose according to their CYP3A5 genotypes (0.075 mg/kg body weight twice a day in CYP3A5 nonexpressors and a double dose of 0.150 mg/kg body weight twice a day in CYP3A5 expressors), while the control group patients were received tacrolimus at the conventional dose of O.lOmg/kg body weight twice a day. All the patients in two groups were receiving the same triple immunosuppressive therapy of tacrolimus, mycophenolate and prednisone and were followed up for more than three months. The comparison between the study group and the control group was made on the rate of patients that had achieved therapeutic blood concentration ((6-10) ng/mL) during the first 7 days postoperation, the rate of patients who needed to adjust tacrolimus dose, the rate of acute rejection (AR) and the occurrence of dose-dependent side effects (such as nephrotoxicity, neurotoxicity, hyperlipidemia and hyperglycaemia) in the first three months postoperation.Results:The rate of patients that had achieved target therapeutic blood concentration during the first 7 days postoperation in the study group was significantly higher than in the control group (62.5%vs 32.6%, P<0.05),while the rate of patients who needed to adjust tacrolimus dose was significantly lower in the study group (35% vs 65.1%,P<0.05). The rate of AR in the first three months postoperation in the study group and the control group was 20.0% and 25.6% respectively, and the occurrence of dose-dependent side effects in the first three months postoperation was 12.5% in the study group and 18.6% in the control group respectively. The rate of AR and dose-dependent side effects was lower in the study group than in the control group, but there was no statistical different between two groups.Conclusion:Adjusting the initial tacrolimus dose based on the patient CYP3A5*3 genotype can effectively help more recipients of different genotypes achieve target therapeutic blood concentration in the initial period after transplantation, reduce the rate of patients who need to adjust tacrolimus dose, that may cut down the rate of AR caused by underimmunosuppression and the rate of dose-dependent side effects caused by overimmunosuppression.