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Noda T, Mizuno S, Mogushi K, Hase T, Iida Y, Takeuchi K, Ishiwata Y, Nagata M. Development of a predictive model for nephrotoxicity during tacrolimus treatment using machine learning methods. Br J Clin Pharmacol 2024; 90:675-683. [PMID: 37921554 DOI: 10.1111/bcp.15953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 10/06/2023] [Accepted: 10/29/2023] [Indexed: 11/04/2023] Open
Abstract
AIM When administering tacrolimus, therapeutic drug monitoring is recommended because nephrotoxicity, an adverse event, occurs at supra-therapeutic whole-blood concentrations of tacrolimus. However, some patients exhibit nephrotoxicity even at the recommended concentrations, therefore establishing a therapeutic range of tacrolimus concentration for the individual patient is necessary to avoid nephrotoxicity. This study aimed to develop a model for individualized prediction of nephrotoxicity in patients administered tacrolimus. METHODS We collected data, such as laboratory test data at tacrolimus initiation, concomitant drugs and tacrolimus whole-blood concentration, from medical records of patients who received oral tacrolimus. Nephrotoxicity was defined as an increase in serum creatinine levels within 60 days of tacrolimus initiation. We built 13 prediction models based on different machine learning algorithms: logistic regression, support vector machine, gradient-boosting trees, random forest and neural networks. The best performing model was compared with the conventional model, which classifies patients according to the tacrolimus concentration alone. RESULTS Data from 163 and 41 patients were used to construct models and evaluate the best performing one, respectively. Most of the patients were diagnosed with inflammatory or autoimmune diseases. The best performing model was built using a support vector machine; it showed a high F2 score of 0.750 and outperformed the conventional model (0.500). CONCLUSIONS A machine learning model to predict nephrotoxicity in patients during tacrolimus treatment was developed using tacrolimus whole-blood concentration and other patient data. This model could potentially assist in identifying high-risk patients who require individualized target therapeutic concentrations of tacrolimus prior to treatment initiation to prevent nephrotoxicity.
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Affiliation(s)
- Tsubura Noda
- Department of Pharmacokinetics and Pharmacodynamics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Bunkyo-ku, Japan
| | - Shotaro Mizuno
- Department of Pharmacokinetics and Pharmacodynamics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Bunkyo-ku, Japan
| | - Kaoru Mogushi
- Innovative Human Resource Development Division, Institute of Education, Tokyo Medical and Dental University (TMDU), Tokyo, Bunkyo-ku, Japan
| | - Takeshi Hase
- Innovative Human Resource Development Division, Institute of Education, Tokyo Medical and Dental University (TMDU), Tokyo, Bunkyo-ku, Japan
| | - Yoritsugu Iida
- Innovative Human Resource Development Division, Institute of Education, Tokyo Medical and Dental University (TMDU), Tokyo, Bunkyo-ku, Japan
| | - Katsuyuki Takeuchi
- Innovative Human Resource Development Division, Institute of Education, Tokyo Medical and Dental University (TMDU), Tokyo, Bunkyo-ku, Japan
| | - Yasuyoshi Ishiwata
- Department of Pharmacy, Tokyo Medical and Dental University Hospital, Tokyo Medical and Dental University (TMDU), Tokyo, Bunkyo-ku, Japan
| | - Masashi Nagata
- Department of Pharmacokinetics and Pharmacodynamics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Bunkyo-ku, Japan
- Department of Pharmacy, Tokyo Medical and Dental University Hospital, Tokyo Medical and Dental University (TMDU), Tokyo, Bunkyo-ku, Japan
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Mochizuki T, Shibata K, Naito T, Shimoyama K, Ogawa N, Maekawa M, Kawakami J. LC-MS/MS method for the quantitation of serum tocilizumab in rheumatoid arthritis patients using rapid tryptic digestion without IgG purification. J Pharm Anal 2022; 12:852-859. [PMID: 36605577 PMCID: PMC9805942 DOI: 10.1016/j.jpha.2022.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 08/15/2022] [Accepted: 08/29/2022] [Indexed: 01/09/2023] Open
Abstract
The quantitation of serum tocilizumab using liquid chromatography tandem-mass spectrometry (LC-MS/MS) method has not been widely applied in clinical settings because of its time-consuming and costly sample pretreatments. The present study aimed to develop a validated LC-MS/MS method for detecting serum tocilizumab by utilizing immobilized trypsin without an immunoglobulin G purification step and evaluate its applicability in the treatment of rheumatoid arthritis (RA) patients administered intravenously or subcutaneously with tocilizumab. The tocilizumab-derived signature peptide was deciphered using a nano-LC system coupled to a hybrid quadrupole-orbitrap mass spectrometer. The serum tocilizumab was rapidly digested by immobilized trypsin for 30 min. The chromatographic peak of the signature peptide and that of the internal standard were separated from the serum digests for a total run time of 15 min. The calibration curve of serum tocilizumab concentration was linear with a range of 2-200 μg/mL. The intra- and inter-day accuracy and relative standard deviation (RSD) were 90.7%-109.4% and <10%, respectively. The serum tocilizumab concentrations in the RA patients receiving intravenous and subcutaneous injections were 5.8-28.9 and 2.4-63.5 μg/mL, respectively. The serum tocilizumab concentrations using the current method positively correlated with those using the enzyme-linked immunosorbent assay, although a systematic error was observed between these methods. In conclusion, a validated LC-MS/MS method with minimal sample pretreatments for monitoring serum tocilizumab concentrations in RA patients was developed.
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Affiliation(s)
- Takashi Mochizuki
- Department of Hospital Pharmacy, Hamamatsu University School of Medicine, Hamamatsu, 431-3192, Japan
| | - Kaito Shibata
- Department of Hospital Pharmacy, Hamamatsu University School of Medicine, Hamamatsu, 431-3192, Japan,Department of Pharmacy, Shinshu University Hospital, Matsumoto, Nagano, 390-8621, Japan
| | - Takafumi Naito
- Department of Hospital Pharmacy, Hamamatsu University School of Medicine, Hamamatsu, 431-3192, Japan,Department of Pharmacy, Shinshu University Hospital, Matsumoto, Nagano, 390-8621, Japan,Corresponding author. Department of Pharmacy, Shinshu University Hospital, Matsumoto, Nagano, 390-8621, Japan.
| | - Kumiko Shimoyama
- Third Division, Department of Internal Medicine, Hamamatsu University School of Medicine, Hamamatsu, 431-3192, Japan
| | - Noriyoshi Ogawa
- Third Division, Department of Internal Medicine, Hamamatsu University School of Medicine, Hamamatsu, 431-3192, Japan
| | - Masato Maekawa
- Department of Laboratory Medicine, Hamamatsu University School of Medicine, Hamamatsu, 431-3192, Japan
| | - Junichi Kawakami
- Department of Hospital Pharmacy, Hamamatsu University School of Medicine, Hamamatsu, 431-3192, Japan
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Chavant A, Jourdil JF, Jouve T, Christians U, Fonrose X, Stanke-Labesque F. A simple and easy-to-perform liquid chromatography-mass spectrometry method for the quantification of tacrolimus and its metabolites in human whole blood. Application to the determination of metabolic ratios in kidney transplant patients. J Chromatogr B Analyt Technol Biomed Life Sci 2021; 1173:122698. [PMID: 33878532 DOI: 10.1016/j.jchromb.2021.122698] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 03/22/2021] [Accepted: 04/01/2021] [Indexed: 11/23/2022]
Abstract
Tacrolimus is the cornerstone of immunosuppressive therapy in solid organ transplantation and its blood concentrations are routinely monitored. Tacrolimus is extensively metabolized into metabolites that are supposed to be nephrotoxic. Yet, few analytical methods have been described to simultaneously quantify tacrolimus and its main metabolites. We developed and validated a simple liquid chromatography-mass spectrometry method for the quantification of tacrolimus and its three desmethylated metabolites, 13-O, 15-O, and 31-O-desmethylated tacrolimus (M-I, M-III, and M-II respectively) in human whole blood. Protein precipitation of 50 µL of whole blood with 100 µL methanol and zinc sulfate was used as a single-extraction procedure. Tacrolimus and its metabolites were quantified using electrospray ionization-triple quadrupole mass spectrometry in combination with selected reaction monitoring detection in the positive ionization mode. The method was validated following FDA recommendations. This method was precise (intra- and inter-assay coefficients of variation: 2.88-7.81% and 3.96-12.10% for low and high levels of internal quality controls, respectively) and accurate (intra- and inter-assay biases: -1.67-10.30%, and -0.77--9.36%, respectively). In adult kidney transplant patients who were treated with tacrolimus prolonged release formulation, the median (10th-90th percentiles) trough concentrations (n = 16) of tacrolimus, M-I, and M-III were 5.85 (3.37-7.09), 0.100 (0.037-0.168), 0.051 (0.03-0.104), respectively. M-II was measured in only 2 trough samples. The metabolic ratios M-I/tacrolimus and M-III/tacrolimus were 0.017 (0.009-0.027) and 0.009 (0.006-0.015) when measured on trough concentration and 0.022 (0.011-0.037) and 0.008 (0.006-0.015) when measured on area under the curves 0-24 h. This method is a suitable and easy-to-perform tool for future pharmacokinetic-pharmacodynamics studies investigating the importance of tacrolimus and its metabolites blood exposure for solid organ graft survival.
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Affiliation(s)
- Anaëlle Chavant
- Laboratory of Pharmacology-pharmacogenetics and Toxicology- Grenoble-Alpes University Hospital, F-38043 Grenoble, France
| | - Jean-François Jourdil
- Laboratory of Pharmacology-pharmacogenetics and Toxicology- Grenoble-Alpes University Hospital, F-38043 Grenoble, France
| | - Thomas Jouve
- Laboratory of Pharmacology-pharmacogenetics and Toxicology- Grenoble-Alpes University Hospital, F-38043 Grenoble, France; Univ. Grenoble Alpes, F-38041 Grenoble, France; Nephrology, Dialysis, Apheresis and Transplantation Department, Grenoble University Hospital, France
| | - Uwe Christians
- iC42 Clinical Research and Development, Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Xavier Fonrose
- Laboratory of Pharmacology-pharmacogenetics and Toxicology- Grenoble-Alpes University Hospital, F-38043 Grenoble, France
| | - Françoise Stanke-Labesque
- Laboratory of Pharmacology-pharmacogenetics and Toxicology- Grenoble-Alpes University Hospital, F-38043 Grenoble, France; Univ. Grenoble Alpes, F-38041 Grenoble, France; INSERM U1300, HP2, F-38041 Grenoble, France.
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Validation of a new automated chemiluminescent anti-SARS-CoV-2 IgM and IgG antibody assay system detecting both N and S proteins in Japan. PLoS One 2021; 16:e0247711. [PMID: 33661990 PMCID: PMC7932516 DOI: 10.1371/journal.pone.0247711] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 02/11/2021] [Indexed: 01/08/2023] Open
Abstract
PCR methods are presently the standard for the diagnosis of Coronavirus disease 2019 (COVID-19), but additional methodologies are needed to complement PCR methods, which have some limitations. Here, we validated and investigated the usefulness of measuring serum antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using the iFlash3000 CLIA analyzer. We measured IgM and IgG titers against SARS-CoV-2 in sera collected from 26 PCR-positive COVID-19 patients, 53 COVID-19-suspected but PCR-negative patients, and 20 and 100 randomly selected non-COVID-19 patients who visited our hospital in 2020 and 2017, respectively. The repeatability and within-laboratory precision were obviously good in validations, following to the CLSI document EP15-A3. Linearity was also considered good between 0.6 AU/mL and 112.7 AU/mL for SARS-CoV-2 IgM and between 3.2 AU/mL and 55.3 AU/mL for SARS-CoV-2 IgG, while the linearity curves plateaued above the upper measurement range. We also confirmed that the seroconversion and no-antibody titers were over the cutoff values in all 100 serum samples collected in 2017. These results indicate that this measurement system successfully detects SARS-CoV-2 IgM/IgG. We observed four false-positive cases in the IgM assay and no false-positive cases in the IgG assay when 111 serum samples known to contain autoantibodies were evaluated. The concordance rates of the antibody test with the PCR test were 98.1% for SARS-CoV-2 IgM and 100% for IgG among PCR-negative cases and 30.8% for SARS-CoV-2 IgM and 73.1% for SARS-CoV-2 IgG among PCR-positive cases. In conclusion, the performance of this new automated method for detecting antibody against both N and S proteins of SARS-CoV-2 is sufficient for use in laboratory testing.
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Naito T, Ohshiro J, Sato H, Torikai E, Suzuki M, Ogawa N, Kawakami J. Relationships between concomitant biologic DMARDs and prednisolone administration and blood tacrolimus exposure or serum CYP3A4/5-related markers in rheumatoid arthritis patients. Clin Biochem 2019; 69:8-14. [DOI: 10.1016/j.clinbiochem.2019.05.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 04/19/2019] [Accepted: 05/06/2019] [Indexed: 11/29/2022]
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Ono H, Suzuki Y, Kaneko T, Tanaka R, Sato F, Sato Y, Mimata H, Itoh H. High‐sensitivity simultaneous quantification of tacrolimus and 13‐
O
‐demethyl tacrolimus in human whole blood using ultra‐performance liquid chromatography coupled to tandem mass spectrometry. Biomed Chromatogr 2019; 33:e4584. [DOI: 10.1002/bmc.4584] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 03/25/2019] [Accepted: 05/10/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Hiroyuki Ono
- Department of Clinical PharmacyOita University Hospital Oita Japan
| | - Yosuke Suzuki
- Department of Clinical PharmacyOita University Hospital Oita Japan
- Department of Medication Use Analysis and Clinical ResearchMeiji Pharmaceutical University Tokyo Japan
| | - Tetsuya Kaneko
- Department of Clinical PharmacyOita University Hospital Oita Japan
| | - Ryota Tanaka
- Department of Clinical PharmacyOita University Hospital Oita Japan
| | - Fuminori Sato
- Department of UrologyOita University Faculty of Medicine Oita Japan
| | - Yuhki Sato
- Department of Clinical PharmacyOita University Hospital Oita Japan
| | - Hiromitsu Mimata
- Department of UrologyOita University Faculty of Medicine Oita Japan
| | - Hiroki Itoh
- Department of Clinical PharmacyOita University Hospital Oita Japan
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Salis F, Descalzo AB, Benito-Peña E, Moreno-Bondi MC, Orellana G. Highly Fluorescent Magnetic Nanobeads with a Remarkable Stokes Shift as Labels for Enhanced Detection in Immunoassays. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1703810. [PMID: 29665269 DOI: 10.1002/smll.201703810] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 01/30/2018] [Indexed: 06/08/2023]
Abstract
Fluorescence immunoassays are popular for achieving high sensitivity, but they display limitations in biological samples due to strong absorption of light, background fluorescence from matrix components, or light scattering by the biomacromolecules. A powerful strategy to overcome these problems is introduced here by using fluorescent magnetic nanobeads doped with two boron-dipyrromethane dyes displaying intense emission in the visible and near-infrared regions, respectively. Careful matching of the emission and absorption features of the dopants leads to a virtual Stokes shift larger than 150 nm achieved by an intraparticle Förster resonance energy transfer (FRET) process between the donor and the acceptor dyes. Additionally, the magnetic properties of the fluorescent beads allow preconcentration of the sample. To illustrate the usefulness of this approach to increase the sensitivity of fluorescence immunoassays, the novel nanoparticles are employed as labels for quantification of the widely used Tacrolimus (FK506) immunosuppressive drug. The FRET-based competitive inhibition immunoassay yields a limit of detection (LOD) of 0.08 ng mL-1 , with a dynamic range (DR) of 0.15-2.0 ng mL-1 , compared to a LOD of 2.7 ng mL-1 and a DR between 4.1 and 130 ng mL-1 for the immunoassay carried out with direct excitation of the acceptor dye.
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Affiliation(s)
- Francesca Salis
- Department of Organic Chemistry, Faculty of Chemistry, Complutense University of Madrid (UCM), 28040, Madrid, Spain
| | - Ana B Descalzo
- Department of Organic Chemistry, Faculty of Chemistry, Complutense University of Madrid (UCM), 28040, Madrid, Spain
| | - Elena Benito-Peña
- Department of Analytical Chemistry, Faculty of Chemistry, Complutense University of Madrid (UCM), 28040, Madrid, Spain
| | - María C Moreno-Bondi
- Department of Analytical Chemistry, Faculty of Chemistry, Complutense University of Madrid (UCM), 28040, Madrid, Spain
| | - Guillermo Orellana
- Department of Organic Chemistry, Faculty of Chemistry, Complutense University of Madrid (UCM), 28040, Madrid, Spain
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Shibata K, Naito T, Okamura J, Hosokawa S, Mineta H, Kawakami J. Simple and rapid LC-MS/MS method for the absolute determination of cetuximab in human serum using an immobilized trypsin. J Pharm Biomed Anal 2017; 146:266-272. [DOI: 10.1016/j.jpba.2017.08.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 08/04/2017] [Accepted: 08/07/2017] [Indexed: 12/18/2022]
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Naito T, Mino Y, Aoki Y, Hirano K, Shimoyama K, Ogawa N, Kagawa Y, Kawakami J. ABCB1 genetic variant and its associated tacrolimus pharmacokinetics affect renal function in patients with rheumatoid arthritis. Clin Chim Acta 2015; 445:79-84. [PMID: 25817604 DOI: 10.1016/j.cca.2015.03.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 03/18/2015] [Indexed: 01/16/2023]
Abstract
BACKGROUND This study aimed to evaluate the blood exposure of and clinical responses to tacrolimus based on genetic variants of CYP3A5 and ABCB1 in patients with rheumatoid arthritis. METHODS Seventy rheumatoid arthritis patients treated with oral tacrolimus once daily were enrolled. Blood concentrations of tacrolimus and its major metabolite 13-O-demethylate at 12h after dosing were determined. The relationships between the tacrolimus pharmacokinetics and efficacy, renal function, and CYP3A5 and ABCB1 genotypes were evaluated. RESULTS Dose-normalized blood concentration of tacrolimus was significantly higher in the CYP3A5*3/*3 group than in the *1 allele carrier group. A lower metabolic ratio of 13-O-demethylate to tacrolimus was observed in the CYP3A5*3/*3 group. The ABCB1 3435TT group had higher dose-normalized blood concentrations of tacrolimus and 13-O-demethylate. The blood tacrolimus concentration was inversely correlated with the estimated glomerular filtration rate (eGFR). ABCB1 C3435T but not CYP3A5 genotype had decreased eGFR. Patients lacking the CYP3A5*3 allele had a higher incidence of tacrolimus withdrawal. CONCLUSION CYP3A5*3 increased the blood exposure of tacrolimus through its metabolic reduction. ABCB1 C3435T led to a higher blood exposure of tacrolimus and its major metabolite. The ABCB1 genetic variant and its associated tacrolimus pharmacokinetics affected renal function in rheumatoid arthritis patients.
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Affiliation(s)
- Takafumi Naito
- Department of Hospital Pharmacy, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan.
| | - Yasuaki Mino
- Department of Hospital Pharmacy, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Yuki Aoki
- Department of Hospital Pharmacy, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan; Department of Clinical Pharmaceutics and Pharmacy Practice, Graduate School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Shizuoka, Japan
| | - Kumi Hirano
- Department of Hospital Pharmacy, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Kumiko Shimoyama
- Department of Rheumatology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Noriyoshi Ogawa
- Department of Rheumatology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Yoshiyuki Kagawa
- Department of Clinical Pharmaceutics and Pharmacy Practice, Graduate School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Shizuoka, Japan
| | - Junichi Kawakami
- Department of Hospital Pharmacy, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
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Hirano K, Naito T, Mino Y, Takayama T, Ozono S, Kawakami J. Impact of CYP3A5 genetic polymorphism on cross-reactivity in tacrolimus chemiluminescent immunoassay in kidney transplant recipients. Clin Chim Acta 2012; 414:120-4. [PMID: 22889968 DOI: 10.1016/j.cca.2012.07.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 07/27/2012] [Accepted: 07/27/2012] [Indexed: 11/30/2022]
Abstract
BACKGROUND Tacrolimus immunoassays possess cross-reactivity with metabolites in the blood. The aim of this study was to evaluate the cross-reactivity in tacrolimus chemiluminescent immunoassay (CLIA) in kidney transplant recipients and to characterize the cross-reactivity according to CYP3A5 genetic polymorphism. METHODS The subjects were 50 kidney transplant recipients receiving low-dose tacrolimus. Blood levels of tacrolimus at 12h (C(12)) measured by CLIA were compared with that by LC-MS/MS using Bland-Altman analysis. The influence of CYP3A5 genotypes on the cross-reactivity in tacrolimus CLIA was evaluated by interaction plots. RESULTS No significant difference was observed in tacrolimus C(12) between the CYP3A5*1/*3 and CYP3A5*3/*3 genotypes. The dose-normalized C(12) of tacrolimus was significantly higher in the CYP3A5*3/*3 genotype than in the CYP3A5*1/*3 genotype. The C(12) ratio of 13-O-demethylate to tacrolimus was significantly lower in the CYP3A5*3/*3 genotype than in the CYP3A5*1/*3 genotype. Tacrolimus C(12) measured by CLIA was 35% higher than that by LC-MS/MS. A higher cross-reactivity was observed in the patients with a tacrolimus C(12) of less than 3 μg/l and CYP3A5*1/*3 genotype. CONCLUSION This study confirmed the cross-reactivity in CLIA in kidney transplant recipients receiving low-dose tacrolimus. High metabolic capacity associated with the CYP3A5*1 genotype affected the cross-reactivity in patients with low tacrolimus levels.
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Affiliation(s)
- Kumi Hirano
- Department of Hospital Pharmacy, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan
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