Genome-Wide Association Study of Acute Renal Graft Rejection.

Acute renal rejection is a major risk factor for chronic allograft dysfunction and long-term graft loss. We performed a genome-wide association study to detect loci associated with biopsy-proven acute T cell-mediated rejection occurring in the first year after renal transplantation. In a discovery cohort of 4127 European renal allograft recipients transplanted in eight European centers, we used a DNA pooling approach to compare 275 cases and 503 controls. In an independent replication cohort of 2765 patients transplanted in two European countries, we identified 313 cases and 531 controls, in whom we genotyped individually the most significant single nucleotide polymorphisms (SNPs) from the discovery cohort. In the discovery cohort, we found five candidate loci tagged by a number of contiguous SNPs (more than five) that was never reached in iterative in silico permutations of our experimental data. In the replication cohort, two loci remained significantly associated with acute rejection in both univariate and multivariate analysis. One locus encompasses PTPRO, coding for a receptor-type tyrosine kinase essential for B cell receptor signaling. The other locus involves ciliary gene CCDC67, in line with the emerging concept of a shared building design between the immune synapse and the primary cilium.

[Anti-NEP and anti-PLA2R antibodies in membranous nephropathy: an update]. / Anticorps anti-EPN et anti-PLA2R dans les glomerulopathies extramembraneuses: le point en 2014.

Membranous nephropathy (MN) is the most common cause for nephrotic syndrome in adults and occurs as an idiopathic (primary) or secondary disease. Since the early 2000's, substantial advances have been made in the understanding of the molecular bases of MN. The neutral endopeptidase (NEP) and the receptor for secretory phospholipase A2 (PLA2R) have been identified as target antigens for circulating and deposited antibodies in allo-immune neonatal and adult " idiopathic " MN, respectively. These antibodies recognize specific antigens of podocytes, precipitate as subepithelial immune complexes and activate complement leading to proteinuria. Anti-PLA2R antibodies are of particular clinical importance. Indeed, they are detected in approximately 70% of primary MN in adults, demonstrating that MN actually is an autoimmune condition specific to the kidney. In Europeans, genome-wide studies have shown an association between alleles of PLA2R1 and HLA DQA1 (class II genes of tissue histocompatibility complex) genes and idiopathic MN. Newly developed diagnostic tests detecting circulating anti-PLA2R antibody and PLA2R antigen in glomerular deposits have induced a change in paradigm in the diagnostic approach of idiopathic MN. Measurement of circulating anti-PLA2R antibody is also very useful for the monitoring of MN activity. However, the mechanisms responsible for the formation of anti-PLA2R antibodies as well as those involved in the progression of MN to end-stage renal disease remain to be defined.

A new HLA allocation procedure of kidneys from deceased donors in the current era of immunosuppression.

INTRODUCTION: It has recently been proposed to replace the current Eurotransplant kidney allocation based primarily on mismatches (MM) at the 3 HLA loci by a simpler system based on full HLA-DR compatibility. The present study analyzes this system in the current era of immunosuppression. METHODS: From 1999 to 2012, 723 renal grafts were performed on 586 patients who were treated with a calcineurin inhibitor, mycophenolate mofetil, and in most cases antilymphocyte globulins. Four groups of HLA MM were compared: (A) A+B 2-4/DR 1-2 MM (n = 397), (B) A+B 2-4 MM/DR 0 MM (n = 106), (C) A+B 0-1 MM/DR 1-2 MM (n = 138), and (D) A+B 0-1/DR 0 MM (n = 82). RESULTS: Acute rejection episodes were less frequent during the first post-transplantation year in group D than in the other groups (P = .018). Patient survival was lower in group A than in the other groups (P = .008). Immunologic graft survival was higher in group D than in the other groups in univariate (P = .015) and multivariate analyses (P = .033; 96.4% vs 90.1% at 10 years). CONCLUSIONS: In the current era of immunosuppression, allocation of kidneys from deceased donors could be performed primarily according to full DR compatibility then to the best A+B matching, affording excellent graft outcome to most recipients.

Patient and graft outcome in current era of immunosuppression: a single centre pilot study.

OBJECTIVES: The present single centre study aims at analyzing the impact on renal allograft outcome of the important changes which occurred in the transplant population and immunosuppressive therapy during the last two decades. METHODS: From 2000 to 2013, 779 single kidney transplantations were performed on 635 patients who all received on an intent-to-treat basis steroids, a calcineurin inhibitor, mycophenolate mofetil and an induction therapy with either antithymocyte globulin or an antagonist directed to the interleukin (IL)-2 receptor. Uni- and multivariate analyses of patient and immunologic graft survival were conducted. RESULTS: The sole factor predicting patient survival is recipient's age: 10-year survival rates are 94·7, 81·6 and 57·9% for the <45, 45-60 and >60 years age groups, respectively (P<0·001). Peak (>50% panel reactive antibodies) anti-human leucocyte antigens (HLA) sensitization, cold ischaemia time and HLA-B and -DR mismatches (MM) influence graft outcome: at 10 years, the difference in 10-year survival rates is 5·9% between grafts from sensitized and not sensitized patients (90·9 vs 96·8%, P = 0·002), 3·8% between grafts with <18 and ≧18 hours cold ischaemia (96·6 vs 92·8%, P = 0·003), 7·3% between grafts with no MM and either B or DR MM versus those with B and DR MM (96·8 vs 89·5%, P = 0·002). CONCLUSION: In our single centre experience, graft survival was most strongly determined by HLA matching, offering excellent long term graft outcome to most patients.

[Twenty-five years of calcineurin inhibitors use in kidney transplantation at Erasme Hospital]. / Vingt-cinq ans d'utilisation des inhibiteurs de la calcineurine en transplantation rénale à l'Hôpital Erasme.

The results and risk factors within a cohort of 1.380 renal allografts treated with a calcineurin inhibitor from 1983 to 2008 at Erasme Hospital were analyzed. Three groups corresponding to successive periods were compared: A, from 1983 to 1992 (n = 463); B, from 1993 to 2000 (n = 470); C, from 2001 to 2008 (n = 447). Patient's survival was lower during period C than during periods A and B (89 vs 85% at 8 years, P = 0,044), due to the recipients age. In contrast, graft survival raised gradually (64, 76 and 81% at 8 years for periods A, B and C respectively, P < 0,001). Several factors significantly influence graft survival: in decreasing order, they are the recipient's age (reduced risk of rejection with age), immunosuppressive protocol (superiority of mycophenolate mofetyl and induction with antibodies directed to the IL2 receptor), HLA sensitization, number of HLA-B+Dr mismatches between recipient and donor, and gender (opposite effects of recipient's and donor's gender). The permanent evaluation of results using multivariate analyses would allow to promptly adapt selection and therapeutic strategies within each transplantation center.

Thrombophilic factors do not predict outcomes in renal transplant recipients under prophylactic acetylsalicylic acid.

A cohort of recipients of renal transplant after 2000 (N=310) was prospectively screened on the day of transplantation and 1 month later for a panel of 11 thrombophilic factors to assess their effect on posttransplant outcomes. All patients received prophylactic acetylsalicylic acid, started before transplantation. The rate of thromboembolic events or acute rejection episodes during the first posttransplant year (primary composite endpoint) was 16.7% among patients free of thrombophilic factor (N=60) and 17.2% in those with >or=1 thrombophilic factor (N=250) (p>0.99). The incidence of the primary endpoint was similar among patients free of thrombophilic factors and those with >or=2 (N=135), or >or=3 (N=53) factors (16.3% and 15.1% respectively; p=1) and in patients who remained thrombophilic at 1 month (15.7%; p=0.84). None of the individual thrombophilic factor present at the day of transplantation was associated with the primary endpoint. The incidence of cardiovascular events at 1-year, serum creatinine at 1-year, 4-year actuarial graft and patient survival were not influenced by the presence of >or=1 thrombophilic factor at baseline (p=NS). In conclusion, the presence of thrombophilic factors does not influence thromboembolic events, acute rejection, graft or patient survival in patients transplanted after 2000 and receiving prophylactic acetylsalicylic acid.

[Experience about more than 2000 renal transplantations at the university of Brussels]. / A propos de 2000 greffes rénales a l'U.L.B.: le parcours d'un patient transplanté rénal en 2007.

Since 1965, more than 2000 renal transplantations (including more than 100 living-donor transplantations) have been performed at the University of Brussels. An end-stage renal disease patient candidate to renal transplantation will be therefore followed from his enrolment on the waiting list to the long-term post-transplant period. Improvement in the outcome of renal transplantation is achieved due to better knowledge in many fields of medicine, such as immunology, infectious disease, metabolic diseases (hyperlipemia, diabetes mellitus), pharmacology, use of immunosuppressive regimen, a more adequate cardiovascular prevention and treatment. If the best results were achieved with kidneys from living donors, the graft survival rate at the University of Brussels was nearly 80% for the last period (2000-2006). Unfortunately, renal transplantation cannot cure certain comorbid conditions and even may promote them: infectious diseases, neoplasia, metabolic disorders (e.a diabetes mellitus, hyperlipemia). Many efforts have to be done to develop less toxic and more immune selective therapeutic strategies. Living donation and extension of the pool of cadaveric donors will reduce the length of time spent on the waiting list and will significantly impact on mortality and morbidity after kidney transplantation.

Conversion from tacrolimus to cyclosporin is associated with a significant improvement of glucose metabolism in patients with new-onset diabetes mellitus after renal transplantation.

BACKGROUND: The incidence of new-onset posttransplant diabetes mellitus (PTDM) is increased in renal transplant patients treated with tacrolimus. METHODS: We retrospectively analyzed fasting plasma glucose and HbA1c levels as well as the dose of glucose-lowering agents in 34 renal transplant patients converted from tacrolimus to cyclosporine (CsA) for PTDM. Diabetes was defined according to current guidelines as repeated fasting plasma glucose (FPG) levels > or =126 mg/dL. RESULTS: At conversion, 11 patients received insulin, 5 received oral agents, and 18 had no glucose-lowering therapy. Fasting plasma glucose levels decreased from 146 +/- 64 mg/dL at conversion to 111 +/- 26 mg/dL at 3 months and 104 +/- 21 mg/dL at 12 months (P < .001). HbA1c levels decreased from 6.8 +/- 0.8% at conversion to 6.0 +/- 0.6% at 12 months (P = .001). Insulin was stopped in 3, the dose reduced in 7, and remained stable in 1 of the patients. The average daily insulin dose among these patients was reduced from 31 +/- 17 units at conversion to 13 +/- 12 units at 12 months (P < .05). There was no significant change in the number of patients treated with oral glucose-lowering agents. Diabetes reversed (fasting plasma glucose < or = 125 mg/dL without glucose-lowering therapy) in 44% (95% confidence interval, 23% to 64%) of patients during the first year after conversion (P < .001). Graft function, blood pressure, and lipid levels remained stable after conversion but the proportion of patients receiving lipid-lowering therapy increased from 18% to 49% (P < .01). CONCLUSIONS: Conversion from tacrolimus to CsA for PTDM was associated with a marked improvement in glucose metabolism and frequent reversal of diabetes.

[The medico-surgical department of nephrology dialysis and renal transplantation]. / Le département médico-chirurgical de Néphrologie Dialyse et Transplantation Rénale.

The Department of Nephrology of the Hospital Erasme, opened 25 years ago, is now performing, each year, 22,000 hemodialysis sessions, 800 patient-weeks of peritoneal dialysis treatment and 70 renal grafts. Scientific contributions of the department deal with vascular access for hemodialysis, susceptibility to infections of dialyzed patients, parathyroid surgery, biocompatibility of dialysis membranes, predictive factors of renal graft survival, immunosuppression with monoclonal antibodies, experimental studies of graft tolerance and rejection, toxic nephropathies. The most original contributions are related to anaphylactoïd reactions in hemodialysis by association of acrylonitrile membranes with inhibition of the converting enzyme, to advantages and side effects of OKT3 monoclonal antibody and to discovery and study of the Chinese herbs nephropathy.

Fibrate-induced increase in blood urea and creatinine: is gemfibrozil the only innocuous agent?

BACKGROUND: Some reports indicate that fibrates can induce renal dysfunction. However, the clinical characteristics of these episodes, and the respective nephrotoxicity of the four main fibrates used-namely, fenofibrate, bezafibrate, ciprofibrate, and gemfibrozil-remain ill defined. METHODS: To better characterize this side-effect, we first reviewed the charts of 27 patients from our institution who developed an impairment of renal function during fibrate therapy. We next analysed the articles (n=24) that contained data on renal function in patients taking fibrates (n=2676). RESULTS: Among our 27 patients, 25 were on fenofibrate therapy, one was taking bezafibrate, and one ciprofibrate. Nineteen were recipients of solid-organ transplants (kidney recipients, n=15; heart or heart-lung recipients, n=4), and eight were non-transplanted patients with some impairment of renal function. Baseline plasma creatinine ranged from 0.9 to 2.9 mg/dl. It increased by a mean of 40% after the start of fibrate therapy. There was a concomitant increase of blood urea values (mean 36%) in most of the patients. Renal function returned to baseline in 18/24 patients after fibrate discontinuation. However, six patients, all transplant recipients, experienced a permanent increase in plasma creatinine. The incidence of fibrate-induced renal dysfunction among our series of kidney transplant recipients was 60%, as it occurred in 15 of the 25 patients who had ever taken fibrates. An increase of mean creatinine values during therapy was described in all papers on fenofibrate (n=7) and bezafibrate (n=8) (range 8-18% and 8-40% respectively), and in three of four papers dealing with ciprofibrate (range 6-16%). No significant renal impairment was described in any of the eight articles reporting data on gemfibrozil therapy. CONCLUSION: Therapy with fenofibrate, bezafibrate, and ciprofibrate may induce renal dysfunction. Gemfibrozil appears to be devoid of this side-effect.

Hypercholesterolemia is associated with increased kidney graft loss caused by chronic rejection in male patients with previous acute rejection.

BACKGROUND: Whereas acute rejection is the main risk factor for the occurrence of chronic rejection, mechanisms in addition to the donor-specific immune response probably contribute to late allograft failure. In this study, we investigated the possible role of hypercholesterolemia in the incidence of chronic kidney graft loss. METHODS: By using the actuarial method, we retrospectively analyzed the long-term loss of cadaveric kidney grafts in patients who had a functioning graft at 1 year and had received a transplant and undergone cyclosporin A therapy in our center between 1983 and 1997. RESULTS: As observed previously, patients with acute rejection during the 1st posttransplant year (n=198) had significantly higher actuarial graft loss at 10 years compared with those free of acute rejection (n=244). In patients free of acute rejection at 1 year, hypercholesterolemia (> or =250 mg/dl) had no impact on graft loss at 10 years. On the contrary, in patients with previous acute rejection, those with hypercholesterolemia (n=59) had a higher immunological (36.0% vs. 19.2%; P<0.01) and overall (50.0% vs. 25.3%; P<0.01) graft loss at 10 years compared with patients with serum cholesterol <250 mg/dl (n=139). Among patients with 1st year acute rejection, hypercholesterolemia was associated with a significant increase in graft loss in male but not in female recipients. Multivariate analysis confirmed that hypercholesterolemia was an independent risk factor for chronic graft loss in male patients (P<0.05). CONCLUSION: Hypercholesterolemia is an independent risk factor for kidney graft loss from chronic rejection in male patients with previous acute rejection. Correction of hypercholesterolemia could help to reduce kidney graft loss caused by chronic rejection in this category of patients.

Mycophenolate mofetil, together with cyclosporin A, prevents anti-OKT3 antibody response in kidney transplant recipients.

OKT3 monoclonal antibody, a murine IgG2a monoclonal antibody targeting the T cell CD3 antigen, elicits a neutralizing humoral response in 20 to 50% of kidney transplant recipients when the concomitant immunosuppression consists of CsA-Sandimmun (SAND) and azathioprine (AZA). In the present study, we investigated the impact of the newer agents, CsA-Neoral (NEO) and mycophenolate mofetil (MMF) on OKT3 sensitization. Sixty-two consecutive kidney transplant recipients received prophylactic OKT3 (5 mg/d) from days 0 to 13, together with steroids. Concomitant immunosuppression consisted of either AZA + SAND (n=20), AZA + NEO (n=31), or MMF + NEO (n=11). The following doses were used: AZA, 2 mg/kg per d from days 0 to 13, then 1 mg/kg per d; MMF, 2 g/d starting on day 1; and CsA, either SAND or NEO, 6 mg/kg per d from day 6. At least two serum samples per month were available during the initial 3 mo for each patient. IgG anti-OKT3 antibodies were first evaluated by enzyme-linked immunosorbent assay. Patients were considered sensitized if their serum scored positive at a dilution > or = 1/1000. Peak titers of IgG anti-OKT3 antibodies and the incidence of patients harboring neutralizing anti-idiotypic antibodies were also determined. A first reduction in OKT3 sensitization was seen in patients receiving Neoral instead of Sandimmun (AZA + SAND: 10 of 20 [50%] patients sensitized versus 6 of 31 [19%] in the AZA + NEO group; P=0.03). This was probably related to the achievement of higher mean CsA trough blood levels in the NEO group during the first month (253+/-44 versus 186+/-49 ng/ml in SAND patients). Peak antibody titers and the proportion of patients with anti-idiotypic antibodies were similar in the AZA + SAND and AZA + NEO groups. A further reduction in the sensitization rate was observed with the replacement of AZA by MMF (MMF + NEO: 0% sensitized patients; P=0.0013). It is concluded that the combination of CsA-Neoral and MMF efficiently prevents sensitization against OKT3.

[Mycophenolate mofetil]. / Mycophenolate mofetil.

Mycophenolate Mofetil (MMF) is a new immunosuppressive agent that selectively inhibits the proliferation of T and B lymphocytes. The use of MMF in renal transplantation significantly reduced the incidence of acute rejection episodes in the first year after transplantation. The main toxicities of MMF are the occurrence of diarrhea and leucopenia. This potent immunosuppressive agent is devoid of the nephrotoxicity of cyclosporin and of the multiple adverse effects of corticosteroids. Clinical trials are currently in progress to assess whether the use of MMF will allow the discontinuation of cyclosporine or corticosteroid therapy without leading to an increased risk of rejection. If results were positive, MMF would represent a significant advance in the field of renal transplantation.

A previously undescribed side effect of icodextrin: overestimation of glycemia by glucose analyzer.

OBJECTIVE: Serious discrepancies between glycemia measurements obtained with an Accutrend Sensor (Boehringer Mannheim GmbH, Mannheim, Germany) type analyzer (based on a glucose dehydrogenase enzymatic reaction) and measurements obtained in the laboratory by a reference method (hexokinase) have been found in an insulin-requiring, diabetic, continuous ambulatory peritoneal dialysis (CAPD) patient treated with icodextrin 7.5% (Extraneal; Baxter Healthcare SA, Castlebar, Ireland), a new osmotic agent for peritoneal dialysis. We therefore investigated the respective role of the Analyzer and of the glucose polymer in this hitherto undescribed problem. DESIGN: Glycemia was measured simultaneously on venous blood using a reference laboratory technique, and on capillary blood using the Accutrend Sensor glucose analyzer in three groups of CAPD patients: 6 patients on Extraneal for at least 1 week, 6 patients receiving their first Extraneal exchange, and 8 patients never exposed to Extraneal. In the first group of patients, glycemia was also measured with another analyzer (Glucocard; Menarini Diagnostics, Firenze, Italy) using a different enzymatic reaction (glucose oxidase). In a separate study, whole blood of a normal subject was spiked with concentrated solutions of glucose and icodextrin and some of its metabolites (maltose, maltotriose, maltopentaose). Once again, comparative measurements of glycemia were performed with the Accutrend Sensor, with two other kits using a glucose dehydrogenase enzyme reaction, and with the hexokinase reference method. RESULTS: In 6 CAPD patients treated with once-daily exchanges with Extraneal for a minimum of 7 consecutive days, we confirmed overestimation of glycemia by the Accutrend Sensor of 65 +/- 26 mg/dL compared to reference values (p < 0.01), and of 69 +/- 25 mg/dL (p < 0.001) compared to measurements obtained with the Glucocard monitor. In 6 other CAPD patients studied at the end of one single icodextrin exchange, overestimation of 61 +/- 11 mg/dL was already present (p < 0.001). On the other hand, in 8 CAPD patients never treated with icodextrin, there was no discrepancy between the Accutrend Sensor readings and reference values. The measurements in spiked blood confirmed that only the Accutrend Sensor overestimates glycemia in the presence of maltose and glucose polymers. The overestimation decreased as the molecular size of the saccharides added to blood increased. There was no overestimation when other kits using a dehydrogenase enzyme were tested. CONCLUSION: The overestimation observed is probably related to the presence of oligosaccharides (mainly maltose), derivatives of glucose polymers present in Extraneal and absorbed via the peritoneal route, in the blood of patients treated with icodextrin. The glucose dehydrogenase characterizing the Accutrend Sensor, an enzyme of the pyrroloquinolinequinone class, very likely reacts with the free reducing group of the glucose molecule located at the end of each saccharide chain. This would not be the case for the Glucocard monitor using glucose oxidase, for other kits using glucose dehydrogenase, and for the reference method based on hexokinase. The Accutrend Sensor type of analyzers are therefore not suitable for regular monitoring of glycemia in diabetic PD patients treated with icodextrin.

The role of human glutathione S-transferase isoenzymes in the formation of glutathione conjugates of the alkylating cytostatic drug thiotepa.

Nonenzymatic and glutathione S-transferase (GST) catalyzed glutathione (GSH) conjugation has been postulated as a mechanism by which alkylating cytostatic drugs can be inactivated intracellularly. In this study, we describe studies on the glutathione-dependent biotransformation of thiotepa (tris(1-aziridinyl)phosphine sulfide), a trifunctional alkylating agent. 31P NMR studies showed that thiotepa is stable in 0.07 M phosphate buffer, pH 7.4 (t1/2 = 3300 min). In the presence of glutathione, the rate of disappearance of thiotepa increased greatly (t1/2 = 282 min). Both monoglutathionyl thiotepa and diglutathionyl thiotepa conjugates were identified by 31P NMR and mass spectrometry. Addition of GST A1-1 (alpha) to an incubation of thiotepa and GSH further increased the rate of disappearance of thiotepa (t1/2 = 100 min) and increased the rate of formation of monoglutathionyl thiotepa. The rate of formation of diglutathionyl thiotepa was not altered, suggesting that the formation of diglutathionyl thiotepa is not catalyzed by GST A1-1. The role of purified human GST on the formation of monoglutathionyl thiotepa was further studied by HPLC. In incubations with 0.2 mM thiotepa, 1 mM GSH, and 40 microM GST, both GST A1-1 and P1-1 enhanced the formation of the monoglutathionyl conjugate 30-35-fold above the nonenzymatic formation, while GST A2-2 and M1a-1a did not catalyze the rate of formation of this conjugate. Kms for the GST A1-1 (alpha) and P1-1 (pi) catalyzed formation of monoglutathionyl thiotepa were in the 5-7 mM range. Since the pH in tumors might be lower than in normal cells, the pH dependency of the GST P1-1 catalyzed formation of monoglutathionyl thiotepa was also studied. At all pHs tested (range, 5.5-8.5), a marked catalytic effect of both GST P1-1 and A1-1 on the formation of monoglutathionyl conjugates was noted. The role of GST on the formation of monoglutathionyl conjugates of tepa (tris(1-aziridinyl)phosphine oxide), the major metabolite formed from thiotepa, was also studied. Both GST A1-1 and P1-1 could enhance the formation of the glutathione conjugate 37-46-fold above the spontaneous levels, while GST M1a-1a and A2-2 again did not increase the rate of formation of this conjugate. The results of these studies show that the aziridine moieties in thiotepa/tepa are substrates for both GST A1-1 and P1-1. Thus, GST catalyzed glutathione conjugation of thiotepa might be an important factor in the development of drug resistance towards thiotepa.