Predictive Modeling of Tacrolimus Dose Requirement Based on High-Throughput Genetic Screening.

Any biochemical reaction underlying drug metabolism depends on individual gene-drug interactions and on groups of genes interacting together. Based on a high-throughput genetic approach, we sought to identify a set of covariant single-nucleotide polymorphisms predictive of interindividual tacrolimus (Tac) dose requirement variability. Tac blood concentrations (Tac C0 ) of 229 kidney transplant recipients were repeatedly monitored after transplantation over 3 mo. Given the high dimension of the genomic data in comparison to the low number of observations and the high multicolinearity among the variables (gene variants), we developed an original predictive approach that integrates an ensemble variable-selection strategy to reinforce the stability of the variable-selection process and multivariate modeling. Our predictive models explained up to 70% of total variability in Tac C0 per dose with a maximum of 44 gene variants (p-value <0.001 with a permutation test). These models included molecular networks of drug metabolism with oxidoreductase activities and the multidrug-resistant ABCC8 transporter, which was found in the most stringent model. Finally, we identified an intronic variant of the gene encoding SLC28A3, a drug transporter, as a key gene involved in Tac metabolism, and we confirmed it in an independent validation cohort.

Long-Term Clinical Impact of Adaptation of Initial Tacrolimus Dosing to CYP3A5 Genotype.

Pretransplantation adaptation of the daily dose of tacrolimus to CYP3A5 genotype is associated with improved achievement of target trough concentration (C0 ), but whether this improvement affects clinical outcomes is unknown. In the present study, we have evaluated the long-term clinical impact of the adaptation of initial tacrolimus dosing according to CYP3A5 genotype: The transplantation outcomes of the 236 kidney transplant recipients included in the Tactique study were retrospectively investigated over a period of more than 5 years. In the Tactique study, patients were randomly assigned to receive tacrolimus at either a fixed dosage or a dosage determined by their genotype, and the primary efficacy end point was the proportion of patients for whom tacrolimus C0 was within target range (10-15 ng/mL) at day 10. Our results indicate that the incidence of biopsy-proven acute rejection and graft survival were similar between the control and the adapted tacrolimus dose groups, as well as between the patients who achieve the tacrolimus C0 target ranges earlier. Patients' death, cancer, cardiovascular events, and infections were also similar, and renal function did not change. We conclude that optimization of initial tacrolimus dose using pharmacogenetic testing does not improve clinical outcomes.

Severe cryptococcal-associated neurological immune reconstitution inflammatory syndrome in a renal transplant recipient treated with adalimumab.

Cryptococcosis is a major concern in organ transplant recipients. A decrease in immunosuppressants following the initiation of antifungal therapy is currently recommended, but can occasionally be complicated by the onset of immune reconstitution inflammatory syndrome (IRIS). We report on a case of cryptococcosis in a kidney transplant recipient, compounded by severe neurological IRIS, the outcome of which was unfavorable despite the use of anti-tumor necrosis factor-alpha monoclonal antibodies.

Five-year results of a randomized trial comparing de novo sirolimus and cyclosporine in renal transplantation: the SPIESSER study.

Calcineurin inhibitors improve acute rejection rates and short-term graft survival in renal transplantation, but their continuous use may be deleterious. We evaluated the 5-year outcomes of sirolimus (SRL) versus cyclosporine (CsA) immunosuppressive treatment. This observational study was an extension of the SPIESSER study where deceased donor kidney transplant recipients were randomized before transplantation to a SRL- or CsA-based regimen and followed up 1 year. Data from 131 (63 SRL, 68 CsA) out of 133 patients living with a functional graft at 1 year were collected retrospectively at 5 years posttransplant. Seventy percent of CsA patients versus 54% of SRL patients were still on the allocated treatment at 5 years (p = 0.091), most discontinuations in each group being due to safety issues. In intent-to-treat, mean MDRD eGFR was higher with SRL: 54.2 versus 45.3 mL/min with CsA (p = 0.019); SRL advantage was greater in on-treatment analyses. There were no differences for patient survival (p = 0.873), graft survival (p = 0.121) and acute rejection (p = 0.284). Adverse events were more frequent with SRL (80% vs. 60%, p = 0.015). Results confirmed the high SRL discontinuation rate due to adverse events. Nevertheless, a benefit was evidenced on renal function in patients (more than 50%) still on treatment at 5 years.

Fumagillin-induced aseptic meningoencephalitis in a kidney transplant recipient with microsporidiosis.

Microsporidiosis is an opportunistic infection in organ transplant recipients and patients with other cellular immunodeficiency. Fumagillin is an effective treatment against Enterocytozoon bieneusi, one of the two main species causing the microsporidiosis involved in human diseases. We report the first case, to our knowledge, of a probable drug-induced aseptic meningoencephalitis, after administration of fumagillin in a kidney transplant recipient with microsporidiosis.

Efficacy and safety of early cyclosporine conversion to sirolimus with continued MMF-four-year results of the Postconcept study.

Calcineurin inhibitor (CNI) withdrawal has been used as a strategy to improve renal allograft function. We previously reported that conversion from cyclosporine A (CsA) to sirolimus (SRL) 3 months after transplantation significantly improved renal function at 1 year. In the Postconcept trial, 77 patients in the SRL group and 85 in the CsA group were followed for 48 months. Renal function (Cockcroft and Gault) was significantly better at month 48 (M48) in the SRL group both in the intent-to-treat population (ITT): 62.6 mL/min/1.73 m(2) versus 57.1 mL/min/1.73 m(2) (p = 0.013) and in the on-treatment population (OT): 67.5 mL/min/1.73 m(2) versus 57.4 mL/min/1.73 m(2) (p = 0.002). Two biopsy proven acute rejection episodes occurred after M12 in each group. Graft and patient survival were comparable (graft survival: 97.4 vs. 100%; patient survival: 97.4 vs. 97.6%, respectively). The incidence of new-onset diabetes was numerically increased in the SRL group (7 vs. 2). In OT, three cancers occurred in the SRL group versus nine in the CsA group and mean proteinuria was increased in the SRL group (0.42 ± 0.44 vs. 0.26 ± 0.37; p = 0.018). In summary, the renal benefits associated with conversion of CsA to SRL, at 3 months posttransplantation, in combination with MMF were maintained for 4 years posttransplantation.

Efficacy on renal function of early conversion from cyclosporine to sirolimus 3 months after renal transplantation: concept study.

Sirolimus (SRL) allows to minimize the use of cyclosporine (CsA), but de novo administration after transplantation is associated with various complications. We report a prospective, open-label, multicenter randomized study to evaluate conversion from a CsA-based regimen to a SRL-based regimen 3 months after transplantation. One hundred ninety-two of a total of 237 patients were eligible at 3 months to be converted to SRL (n = 95) or to continue CsA (n = 97). All patients were also given mycophenolate mofetil (MMF) and oral steroids, planned to be discontinued at month 8. The primary endpoint, the clearance estimated according to Cockcroft and Gault at week 52, was significantly better in the SRL group (68.9 vs. 64.4 mL/min, p = 0.017). Patient and graft survival were not statistically different. The incidence of acute rejection episodes, mainly occurring after withdrawal of steroids, was numerically but not statistically higher in the SRL group (17% vs. 8%, p = 0.071). Sixteen patients discontinued SRL, mainly for adverse events (n = 11), and seven patients discontinued CsA for renal failure or acute rejection. Significantly, more patients in the SRL group reported aphthous, diarrhea, acne and high triglyceride levels. Conversion CsA to SRL 3 months after transplantation combined with MMF is associated with improvement in renal function.

Interstitial fibrosis quantification in renal transplant recipients randomized to continue cyclosporine or convert to sirolimus.

Conversion from cyclosporine (CsA) to sirolimus at week 12 after kidney transplantation is associated with a significant improvement in renal function. The aim of this analysis was to investigate the effect of this conversion on interstitial fibrosis (IF), a hallmark of chronic allograft injury, in patients taking part in the CONCEPT trial. This multicenter, prospective, trial included 193 renal recipients randomized at week 12 to switch from CsA to sirolimus or to continue CsA, with mycophenolate mofetil. Routine biopsy with automated, quantified assessment of IF by a program of color segmentation was performed at 1 year in 121 patients. At 1 year, renal function was significantly improved in the conversion group as assessed by estimated GFR (MDRD) and measured GFR. Biopsy results, however, showed no between-group difference in percentage of IF. Calculated GFR at 1 year was significantly associated with the percentage of IF (p = 0.004, R(2)= 0.07). By multivariate analysis diabetic patients had more fibrosis than non-diabetic patients. In conclusion, although kidney transplant patients converted from CsA to sirolimus showed significant improvement in renal function, we found no difference of IF on 1-year biopsies.

[Medical and economic evaluation of new peritoneal dialysis solutions]. / Evaluation médico-économique des nouvelles solutions en dialyse péritonéale.

Conventional peritoneal dialysis solutions are mostly bioincompatible in relationship with a low pH, a high glucose and glucose degradation products (GDP) concentrations inducing anatomical and functional peritoneal membrane alterations. Use of icodextrin solution instead of glucose hypertonic solution preserves peritoneal membrane minimizing glucose exposure and its peritoneal absorption. Physiological fluids with a neutral pH and less GDP seem to have a positive effect on residual renal function which declines more slowly when they are early prescribed, before highly damaged and sclerotic kidneys. Preliminary data show that patients and technique survivals are better when physiological solutions are used either for diabetic and non diabetic patients. However, these new solutions do not improve peritonitis rates except for bicarbonate solutions but this fact must still be confirmed by other studies. In spite of a higher cost, physiological solutions must be proposed mainly for patients with a low comorbidity index and a high life expectancy.

Immunoglobulin A nephropathy. Quantitative immunohistomorphometry of the tonsillar plasma cells evidences an inversion of the immunoglobulin A versus immunoglobulin G secreting cell balance.

Primary IgA nephropathy (Berger's disease) is characterized by renal deposits of IgA, the origin of which is still unknown. However, several clinical and biological findings suggest that these immunoglobulins might have a mucosal origin, and that such patients should present mucosal abnormalities. This paper reports the results of the immunohistomorphometrical analysis of tonsillar plasma cells from seven patients suffering from Berger's disease and seven controls also with recurrent tonsillitis. IgG, IgA, and IgM-secreting cells were enumerated after immunofluorescent staining of serial frozen-cut sections from 20 tonsils. In controls, a predominance of the IgG-secreting population, similar to this reported in the literature was observed (65% of IgG secreting cells and 29% of IgA plasma cells), while an inversion in the patients' plasma cells percentages was evidenced (IgG:37%, IgA:56%). This increment in the IgA population was paralleled by an augmentation of the number of dimeric IgA-secreting cells (75% of IgA plasma cells), stained both for cytoplasmic IgA and J chain. In controls, the latter cells were in similar proportions as previously reported by others (45% of IgA plasma cells). These results demonstrate an imbalance in the IgA-producing system of patients with Berger's disease, which is in keeping with the hypothesis favoring a mucosal origin for the mesangial IgA present in their kidneys.

Cyclosporine monitoring in peripheral blood mononuclear cells: feasibility and interest. A prospective study on 20 renal transplant recipients.

Cyclosporine (CsA) has potent immunosuppressive properties, reflecting its ability to block the transcription of cytokine genes (mainly interleukin 2) in CD4+ T lymphocytes, markedly improving transplantation outcomes in the past 20 years. CsA pharmacokinetic variability and renal toxicity require whole blood (WB) monitoring by 4-hour area under the drug concentration curves (AUC0-4) or 2-hour postdose concentration (C2) monitoring. Nevertheless, graft rejection can occur despite target blood levels, suggesting that WB monitoring does not guarantee optimal immunosuppression. For a decade, pharmacologists and clinicians have worked to optimize CsA doses; some authors, inspired by its mechanism of action, have proposed therapeutic drug monitoring using peripheral blood mononuclear cells (PBMC; lymphocytes and monocytes). The aim of this study was to assess the feasibility and interest of CsA monitoring in PBMC ([CsA]PBMC). We also measured in vitro distribution of CsA in CD4+ and CD4- subsets.

The evolution of weight and body composition in renal transplant recipients: Two-year longitudinal study.

UNLABELLED: Previous series have reported weight gain after kidney transplantation. However few studies have investigated the body composition after kidney transplantation, particularly during longitudinal follow-up. In this prospective study, we assessed the changes in body composition after kidney transplantation. We also analyzed the effect of steroid withdrawal from the immunosuppressive regimen on weight gain and body composition. METHODS: Thirty-eight cadaveric kidney transplant recipients were followed for 2 years posttransplant. Total and segmental body composition were measured by dual energy X-ray absorptiometry (DEXA) at the time of transplantation as well as 3, 6, 12, and 24 months later. RESULTS: In 28 patients (group A), prednisone was stopped by month 6, whereas, in 10 patients (group B), it was continued throughout the study. In the overall patient group, there were no significant changes in body weight. However, a trend to increased weight was observed in group B. In this group, patients showed an early increase in total body fat with a central accumulation of fat mass that was maintained during the follow-up period. On the other hand, total lean mass increased significantly in group A but did not change significantly in group B. CONCLUSION: In summary, overall the group showed no major changes in body weight during the 2 years after transplantation. Steroid withdrawal in kidney transplant recipients may have a significant positive effect on body composition.

Long-term results of monoclonal anti-Il2-receptor antibody versus polyclonal antilymphocyte antibodies as induction therapy in renal transplantation.

We compared the influence of induction therapy on 5-year patient and graft survival as well as on renal function in 100 kidney graft recipients at low immunological risk treated with antilymphocyte globulin (n = 50) versus anti-IL-2R monoclonal antibody (n = 50) in a prospective multicenter study. Long-term immunosuppressive treatment included cyclosporine, mycophenolate mofetil, and a short course of steroids in all patients. Five year graft (86% vs 86%) and patient (94% vs 94%) survivals were identical in both study arms. Moreover, neither serum creatinine or proteinuria were significantly different between the two groups. Our results showed that the choice of the induction therapy seemed to not have a major impact on long-term outcomes among renal recipients at low immunological risk.

Pharmacokinetics of mycophenolic acid in kidney transplant patients receiving sirolimus versus cyclosporine.

INTRODUCTION: Mycophenolic acid (MPA) pharmacokinetics exhibit large variability in transplant recipients and may be altered due to concurrent immunosuppressants. Little is known about the influence of sirolimus (SRL) on MPA pharmacokinetics in kidney transplant patients. METHODS: We studied the areas under concentration-time curves (AUC) for MPA in 15 patients receiving immunosuppression combining SRL with mycophenolate mofetil (MMF). The pharmacokinetic measurements were performed in all patients using three MMF dosing regimens (0.5 g twice a day, 0.75 g twice a day, 1 g twice a day). Similar blood AUC profiles were also sampled from 12 patients treated with a fixed dose of MMF 1 g twice a day and cyclosporine (CsA). MPA was measured using HPLC; the AUC0-12 of MPA was determined by the trapezoidal method using four sampling time points: C0, C1, C3, C5. RESULTS: While patients on SRL were receiving 0.75 g MMF twice a day, mean AUC0-12 and C0 values of MPA were comparable to those of patients receiving CsA and 1 g MMF twice a day (54.1 +/- 17.6 and 3 +/- 1.87 vs 51.7 +/- 16.7 mg.h/L and 2.76 +/- 1.57 mg/L, respectively). On the other hand, 0.5 g MMF twice a day with SRL therapy resulted in AUC0-12 and C0 values of MPA of 32.3 +/- 12.6 mg.h/L and 2.32 +/- 1.72 mg/L, respectively, whereas, 1 g MMF twice a day with SRL resulted in AUC0-12 and C0 values of MPA of 70.9 +/- 19.3 mg.h/L and 4.7 +/- 2.44 mg/L, respectively. CONCLUSIONS: These findings demonstrate that MPA exposure in the presence of SRL is higher than that with CsA. It appears that the MMF dose should be reduced to 0.75 g twice a day in patients receiving SRL to obtain AUC0-12 of MPA levels comparable to that in patients treated with CsA and MMF 1 g twice a day.

[Renal lymphangiectasia, a rare case of perirenal infiltration]. / La lymphangiectasie rénale, un cas rare d'infiltration périrénale.

Renal lymphangiectasia is a bilateral cystic infiltration of the perirenal and parapelvic space which is caused by the obstruction of the renal lymphatic tissue. To our knowledge only numbers have been reported in the literature. Renal lymphangiectasia usually asymptomatic and incidentally diagnosed has absolutely no effect on the patient outcome. Radiological imaging is typical so that the diagnosis does not need to be confirmed by a cyst punction. The lack of knowledge concerning renal lymphangiectasia make it usually confused with another cause of polycystic renal infiltration, such as the polycystic kidney disease. We report herein a case of renal lymphangiectasia diagnosed incidentally by an abdominal ultrasonography.

Factors predicting the long-term success of maintenance cyclosporine monotherapy after kidney transplantation.

BACKGROUND: The theoretical aim of maintenance cyclosporine monotherapy (mCsA) after kidney transplantation is to reduce the incidence of the metabolic complications of corticosteroids and to minimize the adverse effects of excessive long-term immunosuppression. This study was performed in low-immunological-risk cadaveric kidney transplant recipients to evaluate the risks and benefits of mCsA and the long-term graft survival, and to determine the factors predicting success of this policy. METHODS: The multicenter retrospective study was conducted in 329 Caucasian patients receiving mCsA out of 728 first cadaveric kidney transplant recipients. The inclusion criteria were: HLA antibodies < or =25%, serum creatinine <200 micromol/L, and no rejection or only one rejection episode. At the end of the study, we compared the group of patients successfully treated with mCsA (successful group) with those requiring additional immunosuppressive agents (unsuccessful mCsA group). RESULTS: Overall patient and graft survival rates for the 728 first cadaveric graft were 92% and 64%, respectively, at 8 years. Out of 329 patients enrolled in mCsA, 240 were maintained on this treatment and 89 were withdrawn (3 deaths, 18 graft losses, 68 functional grafts). The 8-year graft survival in the 329 enrolled mCsA patients was 84%, 95% in the successful mCsA group, and 70% in the unsuccessful mCsA group. Multivariate analysis showed that the factors predicting success of mCsA were: donor age <40 years (P = 0.001), serum creatinine at mCsA initiation <125 micromol/L (P = 0.02), no rejection episode before mCsA initiation (P = 0.005), and glomerulopathy as the primary renal disease (P = 0.001). CONCLUSION: Numerous kidney transplant recipients with a low immunological risk and good and stable renal function may benefit from discontinuation of prednisone and azathioprine in order to reduce the complications related to these drugs. This therapeutic approach had no adverse impact on the overall long-term graft survival for "low risk" and successful patients.

Clinical pharmacokinetics of ketoprofen after single intravenous administration as a bolus or infusion.

The pharmacokinetics of ketoprofen were evaluated in 29 patients suffering from acute renal colic following a single intravenous administration as a bolus or short infusion (1.5 and 2 hours), and after a loading dose and a 24-hour infusion. Serum concentrations of ketoprofen were measured by high pressure liquid chromatography. The mean (+/- SD) values of clinical parameters were as follows: distribution half-life = 0.34 +/- 0.19 h; elimination half-life = 2.05 +/- 0.58 h; kel = 0.968 +/- 0.282 h-1; k21 = 0.943 +/- 0.425 h-1; k12 = 1.004 +/- 0.708 h-1; volume of central compartment = 5.58 +/- 1.67L; volume of tissue compartment = 5.14 +/- 2.12L; plasma clearance = 5.10 +/- 1.14L/h. These results concur with previously published data obtained after oral or intramuscular administration. According to clinical observations, administration of a ketoprofen bolus suppressed pain within 5 to 30 minutes; the administration of a loading dose and a 24-hour infusion is almost never followed by a recurrence of pain, and this regimen was proposed as the dosage schedule of ketoprofen to treat renal colic.

Pharmacokinetics of fluconazole in patients undergoing continuous ambulatory peritoneal dialysis.

The pharmacokinetics of fluconazole given orally (100 mg) or intraperitoneally (50 and 150 mg) were determined in 15 patients with chronic renal failure who were undergoing continuous ambulatory peritoneal dialysis. The half-life (72 to 85 hours) was intermediate between values obtained in healthy volunteers and in patients with renal insufficiency studied during an interhaemodialysis period. The peritoneal clearance, 0.26 to 0.33 L/h, led to an 18% recovery of administered drug in the dialysates after 48 hours. The peritoneal absorption was slow (time to peak plasma concentration 7 hours) but the peritoneal bioavailability was excellent at 87 +/- 5%. The mean concentrations of fluconazole up to 24 hours were 770 and 1900 micrograms/L after single intraperitoneal doses of 50 and 150 mg, respectively. The volume of distribution (40 to 60 L) did not differ from that determined in patients with normal renal function. In the case of fungal peritonitis essentially attributed to Candida spp., a 6-hour intraperitoneal infusion of fluconazole 150 mg every 2 days appears to be a good regimen to rapidly exceed minimum inhibitory concentrations and treat infection without risk of systemic dissemination of fungi or toxicity.

Quantitative analysis of HCMV DNA load in whole blood of renal transplant patients using real-time PCR assay.

BACKGROUND: Preemptive antiviral treatment of Human Cytomegalovirus (HCMV) disease is a major goal in the management of organ transplant patients. It requires sensitive diagnostic methods. Automated real-time PCR systems have been recently proposed to monitor HCMV infection in such patients. OBJECTIVE: Objectives of this study was to compare a real-time quantitative PCR on whole blood with the HCMV pp65 antigenemia assay in renal transplant recipients, and also to evaluate two different DNA extraction methods. STUDY DESIGN: A total of 248 specimens from 21 patients were tested by quantitative pp65 antigenemia and quantitative real-time PCR. DNA was extracted from whole blood samples using two different methods: a conventional column manual assay and an automated system. RESULTS: Quantification of HCMV DNA using the two extraction methods showed highly similar results (Spearman rank test, r=0.863). We found a significant correlation between DNA quantification by real-time PCR in whole blood and pp65 antigenemia test (Spearman rank test, r=0.767). This correlation was not modified when the HCMV DNA results were normalized by quantification of the albumin cellular gene. In eight patients, HCMV infection was detected earlier with quantitative PCR than with the antigenemia test (mean delay of 11.25 days). HCMV DNA load equivalent of 50 pp65 positive cells/200,000 polymorphonuclear leukocytes (PMNLs) is log4.095 copies per ml of blood. CONCLUSIONS: Real-time PCR in whole blood is a sensitive method for estimating the HCMV genome load in renal transplant patients, and is more rapid and practicable than using PMNLs for pp65 antigenemia tests.