Biomaterial Database

Comparative analysis of tacrolimus (FK506) in whole blood liver transplant recipients by PRO-TRAC enzyme-linked immunosorbent assay and microparticle enzyme immunoassay IMX methods. 1996

M Brunet, and L Pou, and M Torra, and R López, and M Rodamilans, and J Corbella

Department of Toxicology, Hospital Clinic, Barcelona, Spain.

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.

UI	MeSH Term	Description	Entries
D007166	Immunosuppressive Agents	Agents that suppress immune function by one of several mechanisms of action. Classical cytotoxic immunosuppressants act by inhibiting DNA synthesis. Others may act through activation of T-CELLS or by inhibiting the activation of HELPER CELLS. While immunosuppression has been brought about in the past primarily to prevent rejection of transplanted organs, new applications involving mediation of the effects of INTERLEUKINS and other CYTOKINES are emerging.	Immunosuppressant,Immunosuppressive Agent,Immunosuppressants,Agent, Immunosuppressive,Agents, Immunosuppressive
D004797	Enzyme-Linked Immunosorbent Assay	An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed.	ELISA,Assay, Enzyme-Linked Immunosorbent,Assays, Enzyme-Linked Immunosorbent,Enzyme Linked Immunosorbent Assay,Enzyme-Linked Immunosorbent Assays,Immunosorbent Assay, Enzyme-Linked,Immunosorbent Assays, Enzyme-Linked
D006084	Graft Rejection	An immune response with both cellular and humoral components, directed against an allogeneic transplant, whose tissue antigens are not compatible with those of the recipient.	Transplant Rejection,Rejection, Transplant,Transplantation Rejection,Graft Rejections,Rejection, Graft,Rejection, Transplantation,Rejections, Graft,Rejections, Transplant,Rejections, Transplantation,Transplant Rejections,Transplantation Rejections
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D015203	Reproducibility of Results	The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.	Reliability and Validity,Reliability of Result,Reproducibility Of Result,Reproducibility of Finding,Validity of Result,Validity of Results,Face Validity,Reliability (Epidemiology),Reliability of Results,Reproducibility of Findings,Test-Retest Reliability,Validity (Epidemiology),Finding Reproducibilities,Finding Reproducibility,Of Result, Reproducibility,Of Results, Reproducibility,Reliabilities, Test-Retest,Reliability, Test-Retest,Result Reliabilities,Result Reliability,Result Validities,Result Validity,Result, Reproducibility Of,Results, Reproducibility Of,Test Retest Reliability,Validity and Reliability,Validity, Face
D016031	Liver Transplantation	The transference of a part of or an entire liver from one human or animal to another.	Grafting, Liver,Hepatic Transplantation,Liver Transplant,Transplantation, Hepatic,Transplantation, Liver,Hepatic Transplantations,Liver Grafting,Liver Transplantations,Liver Transplants,Transplant, Liver
D016559	Tacrolimus	A macrolide isolated from the culture broth of a strain of Streptomyces tsukubaensis that has strong immunosuppressive activity in vivo and prevents the activation of T-lymphocytes in response to antigenic or mitogenic stimulation in vitro.	Anhydrous Tacrolimus,FK-506,FK506,FR-900506,Prograf,Prograft,Tacrolimus Anhydrous,Anhydrous, Tacrolimus,FK 506,FR 900506,FR900506,Tacrolimus, Anhydrous
D016903	Drug Monitoring	The process of observing, recording, or detecting the effects of a chemical substance administered to an individual therapeutically or diagnostically.	Monitoring, Drug,Therapeutic Drug Monitoring,Drug Monitoring, Therapeutic,Monitoring, Therapeutic Drug
D017248	Enzyme Multiplied Immunoassay Technique	An immunoenzyme test for the presence of drugs and other substances in urine and blood. The test uses enzyme linked antibodies that react only with the particular drug for which the sample is being tested.	EMIT Assay,Assay, EMIT,Assays, EMIT,EMIT Assays