Brunet M, Pou L, Torra M, López R, Rodamilans M, Corbella J
Department of Toxicology, Hospital Clinic, Barcelona, Spain.
Ther Drug Monit. 1996 Dec;18(6):706-9. doi: 10.1097/00007691-199612000-00013.
The macrolide tacrolimus (FK506) is a powerful immunosuppressive drug that acts early in the T-cell activation process and inhibits cytokine gene transcription. Data from several trials in liver transplantation have shown the efficacy of tacrolimus in the prevention of allograft rejection and its potent hepatotrophic effect, which could explain its great success in liver transplantation. However, tacrolimus is not devoid of adverse effects (mainly nephrotoxicity and neurotoxicity) requiring careful blood level monitoring, which is an essential aid in the adjustment of drug dosing. Several methods of analysis are available to measure tacrolimus in whole blood. A new assay based on the enzyme-linked immunosorbent assay (ELISA) technology has been developed. The INCSTAR PRO-TRAC FK506 is a sensitive immunoassay (range, 0.5 to 60 ng/ml), which uses a mouse monoclonal antibody to FK506. Samples are extracted into methanol and dried under nitrogen. The reconstituted extracts are analyzed by ELISA by using 2-h incubation. The aim of this study was to evaluate the ELISA method in routine monitoring of liver transplant patients and to compare the whole blood results with those obtained by Abbott microparticle enzyme immunoassay (MEIA) IMx. Precision studies with 20 samples from 4.37 and 17.1 ng/ml gave within-run total coefficients of variance of 14.4 and 17.4%, respectively. A total of 63 blood samples was analyzed. The mean +/- SD were 9.68 +/- 5.92 and 10.52 +/- 7.54 ng/ml by ELISA and MEIA assays, respectively. There was an acceptable correlation between the methods: ELISA = 1.419 + 0.785 MEIA; Sy x x = 2.639; r = 0.804. Serial tacrolimus measurements (n = 13) in two patients with bilirubin levels > 20 mg/dl yielded mean +/- SD (range) of 11.64 +/- 7.59 ng/ml (2.60-25.40 ng/ml) and 15.55 +/- 10.78 ng/ml (3.60-34.4 ng/mL) by ELISA and MEIA assays, respectively. These discrepancies in concentrations can result from variation in matrix or different cross-reactivities or both in the two tests. We concluded that the INCSTAR PRO-TRAC FK506 is suitable for routine whole blood tacrolimus monitoring.
大环内酯类药物他克莫司（FK506）是一种强效免疫抑制药物，可在T细胞激活过程的早期发挥作用并抑制细胞因子基因转录。来自肝移植多项试验的数据表明，他克莫司在预防同种异体移植排斥反应方面有效，且具有强大的促肝细胞生长作用，这可以解释其在肝移植中取得巨大成功的原因。然而，他克莫司并非没有不良反应（主要是肾毒性和神经毒性），需要仔细监测血药浓度，这对于调整药物剂量至关重要。有几种分析方法可用于测量全血中的他克莫司。一种基于酶联免疫吸附测定（ELISA）技术的新检测方法已被开发出来。INCSTAR PRO - TRAC FK506是一种灵敏的免疫测定法（范围为0.5至60 ng/ml），它使用针对FK506的小鼠单克隆抗体。样本用甲醇提取并在氮气下干燥。复溶后的提取物通过ELISA进行分析，孵育2小时。本研究的目的是评估ELISA方法在肝移植患者常规监测中的应用，并将全血检测结果与雅培微粒酶免疫测定（MEIA）IMx法获得的结果进行比较。对来自4.37和17.1 ng/ml的20个样本进行精密度研究，批内总变异系数分别为14.4%和17.4%。共分析了63份血样。ELISA法和MEIA法测得的平均值±标准差分别为9.68±5.92 ng/ml和10.52±7.54 ng/ml。两种方法之间存在可接受的相关性：ELISA = 1.419 + 0.785 MEIA；Sy x x = 2.639；r = 0.804。对两名胆红素水平>20 mg/dl的患者进行系列他克莫司测量（n = 13），ELISA法和MEIA法测得的平均值±标准差（范围）分别为11.64±7.59 ng/ml（2.60 - 25.40 ng/ml）和15.55±10.78 ng/ml（3.60 - 34.4 ng/mL）。浓度上的这些差异可能是由于两种检测方法中基质的差异、不同的交叉反应性或两者兼而有之。我们得出结论，INCSTAR PRO - TRAC FK506适用于他克莫司全血的常规监测。
