Thrombophilic Genetic Anomalies and Their Association With Dialysis Initiation Age in a Cohort of Lebanese Hemodialysis Patients.

OBJECTIVES: The relationship between chronic kidney disease and cardiovascular disease is complex and bidirectional. This relationship may be partially linked to thrombophilic genetic anomalies that may predispose to the progression of both diseases. MATERIALS AND METHODS: We analyzed blood samples from 102 Lebanese patients with end-stage renal disease and undergoing hemodialysis and 20 randomly selected healthy volunteers for frequencies of 12 cardiovascular disease gene mutations and traditional risk factors. The frequencies of these mutations were calculated and compared in both groups. We stratified patients by quartiles according to their mean score of genetic mutations and traditional risk factors, as well as their mean age at dialysis initiation. Correlation analyses were performed on the various patient groups. RESULTS: We observed a high frequency of mutations in patients on dialysis. Homozygous mutations (> 10% of patients) were observed in the PAI-1 (11%), MTHFR A1298C sequence variant (12.7%), and ACE genes (12%); in addition, the FXIII V34L and PAI-1 4G/5G genotypes were significantly associated with early dialysis initiation (P < .001 and P = .004, respectively). We observed a strong linear relationship between the different scores and age at dialysis initiation, with older patients exhibiting the highest genetic, traditional, and total scores versus those shown in the youngest patients (R2 = 0.72 and P < .001; R2 = 0.98 and P < .001; and R2 =0.96 and P < .001, respectively). CONCLUSIONS: Our results revealed a polygenic thrombophilic profile in our population of Lebanese patients with end-stage renal disease. This profile showed a strong association between early dialysis initiation and specific homozygous cardiovascular disease gene mutations. The cumulative load of these genetic and traditional risk factors may be partly responsible for the increased risk of cardiovascular disease and risk of progression to end-stage renal disease in patients with chronic kidney disease.

Could Salivary Cyclosporine Dosage Replace the Whole Blood Cyclosporine Measurements in Renal Transplant Patients?

BACKGROUND: Cyclosporin (CsA) has been extensively used as the immunosuppressant of choice in renal transplantation. Currently available approaches to assess CsA levels, both in serum and blood, fail to accurately reflect the concentration of the pharmacologically active drug fraction. Free CsA levels in biological fluids (blood or saliva) have been advocated to play an important role. Traditional salivary CsA monitoring tests are based on available archaic salivary techniques that are nonspecific and require large amounts of saliva. The aim of this study was to assess salivary CsA correlation using a novel and more accurate technique and to correlate with CsA levels in blood. MATERIAL AND METHODS: Patients provided blood samples of 2 ml and 2 ml of unstimulated saliva on the same day 2 h after the morning CsA dose (C2). Whole blood levels of CsA were determined using the monoclonal fluorescent polarization immunoassay (FPIA) kit. The FPIA kit was adapted to salivary testing by using a novel extraction method developed and patented under the name of Middle East Research Institute (MERI). Wilcoxon signed rank test compared the differences in blood and salivary CsA. Pearson's correlation coefficient assessed the linear association between blood and salivary CsA concentrations. All analyses were performed using IBM-SPSS version 23 (IBM Corp, Armonk, NY, USA). RESULTS: No significant correlation was observed between blood and salivary CsA levels. CONCLUSION: Salivary CsA concentrations at C2 cannot adequately replace C2 blood levels as an indicator of CsA bioavailability despite improved performance of monoclonal FPIA and application of the MERI technique. More studies may be warranted to design more reliable and less invasive procedures for therapeutic drug monitoring.

Bortezomib as a Novel Approach to Early Recurrent Membranous Glomerulonephritis After Kidney Transplant Refractory to Combined Conventional Rituximab Therapy.

We report a case of early recurrent membranous glomerulonephritis after kidney transplant from a deceased donor. The patient received induction therapy and was discharged with a serum creatinine level of 0.78 mg/dL on triple maintenance immunosuppressive therapy, which included tacrolimus, mycophenolate mofetil, and prednisone. At 7 months after transplant, a graft biopsy for new-onset isolated proteinuria (2.7 g/day) revealed stage 2 recurrent membranous glomerulonephritis. In the face of persistent proteinuria despite combined conservative rituximab therapy over several months and the total eradication of CD20-positive cells, bortezomib was introduced. This resulted in a substantial decline in proteinuria within 2 months and its subsequent disappearance several months later. This was paralleled by a considerable drop in plasma CD34-positive and CD138-positive cell counts. These preliminary observations indicate that recurrent posttransplant membranous glomerulonephritis is associated in part with a B-cell- mediated immunologic process that may involve both CD20-positive and plasma cells. Rituximab-resistant or partially responsive recurrent posttransplant membranous glomerulonephritis may benefit from a proteasome inhibitor-based therapy.

A novel approach in clinical immunosuppression monitoring: drug lymphocyte level.

Like others, we have shown a weak correlation between drug blood levels and clinical outcome and immune response. We recently established that in contrast to blood levels, drug lymphocyte levels are strongly associated with therapeutic efficacy. The discordance between the 2 methodologies regarding clinical outcome and immune response is related mainly to the weak association between drug blood level and target-cell content. This weak association explains the intra- and interindividual variabilities of the therapeutic response. These variations are related mainly to genetic and environmental factors including age, sex, body mass index, organ function, food and subsequent drug absorption, drug interactions, and the availability of extra-target-cell binding sites. These factors seem to influence the modes of action of immunosuppressive agents including drug absorption, metabolism, elimination, transport, extra-target-cell sites, as well as target-cell receptor expression and its binding affinity and specific enzyme baseline activity. Therefore, the cellular fraction of a drug at a fixed dosage is the result of the integration of out-fluxing and in-fluxing forces that are affected by genetic and environmental factors. Any redistribution of the drug between the different binding sites will ultimately affect its bioactivity with no change to its extracellular bioavailability (which is currently determined by pharmacokinetic measurements). Compared with whole-blood or plasma-level measurements, monitoring immunosuppression therapy at the site of action appears to be not only more clinically and immunologically relevant (since it measures the free fraction of the drug at its effector site), but this method also bypasses the potentially complex extracellular factors that affect bioactivity. Since the intracellular content of a drug strongly correlates with its biological effect, monitoring immunosuppression therapy at the site of action is comparable to pharmacodynamic monitoring. It is cost effective and easy to perform in clinical practice and could be used for all immunosuppressive drugs. Since it allows maximal reduction of adverse effects through dosage reduction while maintaining an optimal level of immunosuppression, it should offer a new alternative for immunosuppressive therapy monitoring and tailoring to the individual patient.

Cyclosporine blood level monitoring. Cross-reactivity of anti-cyclosporine A monoclonal with its sulphate metabolite: an in vitro study.

Cyclosporine is metabolized in the liver by the Cytochrom P450 system. Many of the metabolites have been identified and thoroughly studied. However the sulphate metabolite is the least known. The metabolite is hydrophilic and thus it is not easily detectable by HPLC and it is not available in pure form for analysis. We have isolated the metabolite from transplant patients receiving CYA as part of their immunosuppressive therapy. The amino acid sequence was determined and the molecule was synthesised in our laboratories. We have tested the molecule in vitro using cell culture to determine its activity. 1/2 ml of blood+1/2 ml of RPMI was incubated with the following concentration of either CSA or CSS: 0, 25, 50, 100, 250, 500, 750, 1000, 1250, 1500, 2000 ng/ml for 2 and 1/2h at 37 degrees C with 5% CO2. The blood was then stimulated with Ionomycine and PMA (phorpol 12 myristate 13-acetate) for additional 2h. Supernatant was collected and assayed for the concentration of the following cytokines: IL-1a, IL-2, Interferon (IFNa), IL-6, IL-12, TNFa. The cells were used to evaluate the expression of cell activation marker CD69. Blood was assayed for CYA concentration using Abbott TDx assay. Results the level of the metabolite was actually higher than the parent compound indicating that the monoclonal antibodies detected the S form preferentially. The results with other CYA monoclonal was also similar. These results suggest that blood level monitoring of CYA many not be accurate as all the monoclonal antibodies currently used cross react with the metabolites.