The Influence of Donor and Recipient Complement C3 Polymorphisms on Liver Transplant Outcome.

Despite early reports of an impact of complement C3 polymorphism on liver transplant patient and graft survival, subsequent evidence has been conflicting. Our aim was to clarify the contributions of donor and recipient C3 genotype, separately and together, on patient and graft outcomes and acute rejection incidence in liver transplant recipients. Eight donor/recipient groups were analyzed according to their genotype and presence or absence of C3 F allele (FFFS, FFSS, FSFF, FSFS, FSSS, SSFF, SSFS, and SSSS) and correlated with clinical outcomes of patient survival, graft survival, and rejection.

Concentration Monitoring of Plasma Ribavirin: Validation of a Liquid Chromatography-Mass Spectrometric Method and Clinical Sample Collection.

Background: A liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for routine measurement of ribavirin concentrations in EDTA-anticoagulated plasma.

Methods: After protein precipitation, we used a bridged ethylene hybrid (hydrophilic interaction) chromatography column, 0.1 mmol/L ammonium formate pH 3.

Performance of modified-release tacrolimus after conversion in liver transplant patients indicates potentially favorable outcomes in selected cohorts.

Clinical outcomes, dose changes, and dose-equalized tacrolimus concentrations were examined sequentially in 129 liver transplantation (LT) recipients after successful conversion to once daily modified-release tacrolimus either early (within 1 month) or late (>1 month) after LT. The data were compared with data for a group of 60 patients maintained on twice daily conventional-release tacrolimus. Formulation- and time-dependent changes in dose requirements for once and twice daily tacrolimus differed after transplantation.

A direct method for the measurement of everolimus and sirolimus in whole blood by LC-MS/MS using an isotopic everolimus internal standard.

Background: Whole-blood concentrations of the immunosuppressant drugs everolimus and sirolimus should be monitored. A sensitive and selective method offering the detection of both analytes in small sample volumes would optimize the throughput of samples for sirolimus or everolimus analysis. This study reports the validation of a liquid chromatography tandem mass spectrometry method, including a stable isotope internal standard, for the simultaneous measurement of everolimus and sirolimus.

Optimal storage temperature and matrix before analyzing mycophenolic acid.

Background: The immunosuppressant mycophenolic acid (MPA) is widely used in solid organ transplantation and increasingly in hematological conditions and autoimmune disease. Concentration monitoring is generally restricted to specialist laboratories associated with transplant centers to which samples are referred, and delays in transit may occur both from the patient to the local laboratory and from there to the specialist laboratory. The instability of the mycophenolate glucuronides in plasma is well described, but the data on MPA stability in patient samples are limited, particularly in whole blood.

Mycophenolate monitoring in liver, thoracic, pancreas, and small bowel transplantation: a consensus report.

Assessing the value of mycophenolic acid (MPA) monitoring outside renal transplantation is hindered by the absence of any trial comparing fixed-dose and concentration-controlled therapy. However, in liver and thoracic transplantation particularly, clinical trials, observational studies with comparison groups, and case series have described MPA efficacy, exposure/efficacy relationships, pharmacokinetic variability, and clinical outcomes relating to plasma MPA concentrations. On the basis of this evidence, this report identifies MPA as an immunosuppressant for which the combination of variable disposition, efficacy, and adverse effects contributes to interindividual differences seemingly in excess of those optimal for a fixed-dosage mycophenolate regimen.

An investigation into the bias between liquid chromatography-tandem mass spectrometry and an enzyme multiplied immunoassay technique for the measurement of mycophenolic acid.

Mycophenolic acid is now the second most widely used immunosuppressant in solid organ transplantation. Overestimation of mycophenolic acid concentration is a recognized problem of immunoassay, and high-performance liquid chromatography with ultraviolet detection methods have long analysis times and a risk of analyte coelution which may compromise high sample throughput in a clinically meaningful time frame. A novel liquid chromatography-tandem mass spectrometry assay for mycophenolic acid was developed using very small (10 microL) sample volumes and evaluated in comparison with an established immunological assay.

Mycophenolic acid trough level monitoring: relevance in acute and chronic graft versus host disease and its relation with albumin.

Mycophenolate mofetil (MMF) is used to treat acute and chronic graft versus host disease (GvHD). There is scant evidence in the literature about mycophenolic acid (MPA) trough level monitoring in GvHD. We therefore reviewed 32 patients treated with MMF for acute (n = 19) or chronic GvHD (n = 13).

Calcineurin inhibitor sparing in paediatric solid organ transplantation : managing the efficacy/toxicity conundrum.

Despite their efficacy, the calcineurin inhibitors (CNIs) ciclosporin and tacrolimus carry a risk of debilitating adverse effects, especially nephrotoxicity, that affect the long-term outcome and survival of children who are given organ transplants. Simple reduction in dosage of CNI has little or no long-term benefit on their adverse effects, and complete withdrawal without threatening graft outcome may only be possible after liver transplantation. Until the last decade, the only option was to increase corticosteroid and/or azathioprine doses, which imposed additional long-term hazards.

Serial circulating markers of inflammation in biliary atresia--evolution of the post-operative inflammatory process.

Unlabelled: Biliary atresia (BA) may be characterized as an occlusive cholangiopathy affecting both intra- and extra-hepatic parts of the biliary tree, together with a pronounced inflammatory response consisting of hepatic infiltration of (predominantly) CD4+ lymphocytes and macrophages. Soluble cellular adhesion molecules are also known to be raised at the time of portoenterostomy, presumably reflecting intrahepatic disease. We investigated this measurable inflammatory component longitudinally by studying a panel of cellular adhesion molecules (soluble intercellular adhesion molecule-1 [sICAM-1], soluble vascular cell adhesion molecule-1 [sVCAM-1]) and soluble proinflammatory mediators (T helper 1 [interleukin [IL]-2 and interferongamma] and T helper 2 [IL-4 and IL-10]) cytokines and macrophage markers (tumor necrosis factor [TNF] alpha and IL-18) in 21 consecutive infants with BA post-Kasai portoenterostomy (KP).

Immunosuppression in pediatric solid organ transplantation: opportunities, risks, and management.

The pediatric transplant community stands at a time of unprecedented choice of immunosuppressive agents - and with a legacy of morbidity from those agents used in the previous two decades. This review considers the clinical utility and side-effect profiles of immunosuppressants used widely in current practice (e.g.

Soluble adhesion molecule profiling in preoperative infants with biliary atresia.

Objective: Intercellular adhesion molecule (ICAM) expression in liver and bile duct remnant is a feature of the inflammatory component of biliary atresia (BA). Circulating levels of such soluble adhesion molecules (SAM) should reflect intrahepatic disease and would prove a useful adjunct in the evaluation of BA.

Study Design: Serum ICAM-1 (sICAM-1), serum vascular cell adhesion molecule (sVCAM-1), and serum E selectin (sE-selectin) were measured by enzyme-linked immunosorbent assay in infants with BA at the time of portoenterostomy and stratified by outcome.

Low hematocrit and serum albumin concentrations underlie the overestimation of tacrolimus concentrations by microparticle enzyme immunoassay versus liquid chromatography-tandem mass spectrometry.

Background: Rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods are used increasingly for tacrolimus (TRL) monitoring but show a negative difference with respect to a microparticle immunoassay (MEIA). This report examines possible reasons for this difference between methods.

Methods: We collected 1156 blood samples from 277 adult and 121 pediatric recipients of liver, renal, and bone marrow grafts or hepatocyte or pancreatic islet cell implants.

Monitoring mycophenolate in liver transplant recipients: toward a therapeutic range.

Predose plasma mycophenolic acid (MPA) concentrations measured with a semi-automated enzyme-multiplied immunoassay were related to adverse events (e.g., rejection, leukopenia, infection), drug dose, and clinical status in 147 adult and 63 pediatric liver allograft recipients receiving adjunctive immunosuppression with mycophenolate mofetil (MMF).

Mycophenolic acid pharmacokinetics in pediatric liver transplant recipients.

The aim of this study is to study mycophenolic acid (MPA) pharmacokinetics in stable pediatric liver transplant recipients and determine which times best represent the area under the concentration versus time curve (AUC) of MPA plasma concentrations. MPA pharmacokinetic profiles were determined in 21 liver transplant recipients (age, 2 to 15 years; 12 boys) administered mycophenolate mofetil (MMF) for at least 6 months. Ten patients were coadministered cyclosporine A (CsA), and 11 patients were coadministered tacrolimus (Tac).

Induction of cytochrome P450 enzymes in cultured precision-cut human liver slices.

Precision-cut human liver slices obtained from 11 donors were cultured for 72 h in a defined medium (serum free Williams' medium E) supplemented with 0.1 microM insulin and 0.1 microM dexamethasone (DEX).

Inhibition of zaleplon metabolism by cimetidine in the human liver: in vitro studies with subcellular fractions and precision-cut liver slices.

1. The effect of cimetidine on the metabolism of zaleplon (ZAL) in human liver subcellular fractions and precision-cut liver slices was investigated. 2.

Mycophenolic acid and mycophenolic acid glucuronide pharmacokinetics in pediatric liver transplant recipients: effect of cyclosporine and tacrolimus comedication.

Determinants of the wide interindividual variability of the pharmacokinetics of mycophenolic acid (MPA) in 21 stable pediatric liver transplant recipients were investigated in relation to the kinetics of the drug's major phenolic glucuronide metabolite (MPAG), cyclosporin (CsA), or tacrolimus (Tac) co-medication and liver and renal function. Trough concentrations (C(0) ) most reliably predicted the area under the curve (AUC) of 0-7 hours MPA plasma concentrations (r (2) = 0.650).

Thiopurine methyltransferase phenotype and genotype in relation to azathioprine therapy in autoimmune hepatitis.

Background/aims: Toxicity and efficacy of azathioprine is governed partly by the activity of thiopurine methyltransferase (TPMT). Azathioprine has been used for many years, with corticosteroids or alone, for the treatment of autoimmune hepatitis (AIH) but no studies of TPMT phenotype and genotype in relation to response to the drug in AIH have been published.

Methods: Erythrocyte TPMT activities were measured by a radioincorporation assay in 72 consecutive outpatients with AIH, 53 of whom were genotyped for the commonest defective alleles in Europeans (TPMT*3A, *3B and *3C) by restriction fragment length polymorphism analysis.

In vitro pentamer formation as a biomarker of tacrolimus-related immunosuppressive activity after liver transplantation.

Therapeutic drug monitoring of tacrolimus (FK) is widely performed to assist adjustments of drug dosage but may be an inadequate surrogate of the immunosuppression induced. The aim of this investigation was to develop an alternative method for measuring FK-related immunosuppressive activity in blood samples from liver transplant recipients. A pentamer formation assay (PFA) was devised based on the attachment of the 12 kDa FK-binding protein (FKBP12) to microtitre plates in the presence of calcineurin, calmodulin, Ca++ and FK.

Comparison of five cyclosporin immunoassays with HPLC.

High performance liquid chromatography (HPLC) is the reference method for cyclosporin (CyA) measurements but therapeutic monitoring of the drug is frequently made using the more practical immunoassays. Cross-reactivity with CyA metabolites may compromise the specificity of immunoassays, particularly in liver graft recipients where metabolites may accumulate. The aim of this study was to compare with HPLC the performance of two recently introduced CyA immunoassays (the AxSYM fluorescent polarisation immunoassay (FPIA) and non-extraction CEDIA assay).

Differential maintenance of cytochrome P450 enzymes in cultured precision-cut human liver slices.

The maintenance of the major hepatic cytochrome P450 (CYP) enzymes has been studied in precision-cut human liver slices cultured for up to 72 h in supplemented RPMI 1640 medium. The relative apoprotein levels of 11 CYP enzymes were determined using a panel of antipeptide antibodies. In addition, 7-ethoxyresorufin O-deethylase, tolbutamide methylhydroxylase, debrisoquine 4-hydroxylase, and testosterone 6beta-hydroxylase activities were determined as enzymatic markers for CYP1A2, CYP2C9, CYP2D6, and CYP3A4, respectively.