A reliable method to assess the water permeability of a dialysis system: the global ultrafiltration coefficient.

Background: Recent randomized controlled trials suggest that sufficiently high convection post-dilutional haemodiafiltration (HC-HDF) improves survival in dialysis patients, consequently this technique is increasingly being adopted. However, when performing HC-HDF, rigorous control systems of the ultrafiltration setting are required. Assessing the global ultrafiltration coefficient of the dialysis system [GKD-UF; defined as ultrafiltration rate (QUF)/transmembrane pressure] or water permeability may be adapted to the present dialysis settings and be of value in clinics. Methods: GKD-UF was determined and its reproducibility, variability and influencing factors were specifically assessed in 15 stable patients routinely treated by high-flux haemodialysis or HC-HDF in a single unit. Results: GKD-UF invariably followed a parabolic function with increasing QUF in dialysis and both pre- and post-dilution HC-HDF (R2 constantly >0.96). The vertex of the parabola, GKD-UF-max and related QUF were very reproducible per patient (coefficient of variation 3.9 ± 0.6 and 3.3 ± 0.3%, respectively) and they greatly varied across patients (31­42 mL/h−1/mmHg and 82­100 mL/min, respectively). GKD-UF-max and its associated QUF decreased during dialysis treatment (P < 0.01). The GKD-UF-max decrease was related to weight loss (R2 = 0.66; P = 0.0015). Conclusions: GKD-UF is a reliable and accurate method to assess the water permeability of a system in vivo. It varies according to dialysis setting and patient-related factors. It is an objective parameter evaluating the forces driving convection and identifies any diversion of the system during the treatment procedure. It is applicable to low- or high-flux dialysis as well as pre- or post-dilution HDF. Thus, it may be used to describe the characteristics of a dialysis system, is suitable for clinical use and may be of help for personalized prescription.

An epidemic of Pneumocystis jiroveci pneumonia in a renal transplantation center: role of T-cell lymphopenia.

Although only 2 cases of Pneumocystis jiroveci pneumonia were observed in our center between 2004 and 2009, we diagnosed 9 cases in 2010. Each patient had been in contact in the hospital with at least 1 other patient suffering P jiroveci pneumonia. Genotyping of P jiroveci pneumonia strains demonstrates a total homogeneity of the DNA sequences in the 7 patients already analyzed. CD4+ lymphocyte count was significantly lower at M3 in P jiroveci pneumonia patients than in controls. Our clinical and molecular data confirm that interhuman transmission of P jiroveci is possible, particularly to lymphopenic transplant recipients.

Monthly screening for BK viremia is an effective strategy to prevent BK virus nephropathy in renal transplant recipients.

BACKGROUND: BK polyomavirus virus (BKV) nephropathy (BKVN) is the most common viral infection that affects renal allografts. Because a specific antiviral therapy is lacking, BKVN may result in graft dysfunction and/or loss. We prospectively analyzed whether monthly nucleic acid testing (NAT) for BKV replication in blood and immediate reduction of immunosuppression (IS) could prevent BKVN. METHODS: NAT was performed at monthly intervals for 6 months and then at 12 months in 119 de novo renal transplant recipients. In viremic patients (presumptive BKVN), a graft biopsy was systematically performed and IS was immediately reduced. RESULTS: BKV viremia occurred in 13 (10.9%) patients after a median time of 90 days (23-241); 77% of patients were viremic before month 4. After reduction of IS, viral load was undetectable in 11 patients, remained low in 1, and continued to increase in 1 patient who developed definitive BKVN despite reduction of IS, and finally returned to dialysis 6 months after transplantation. CONCLUSION: BKV infection is an early complication. Monthly NAT in blood during the first 6 months and immediate reduction of IS in viremic patients almost completely prevent definitive BKVN.

[Thrombotic microangiopathy following kidney transplantation revealing factors H and I deficiencies]. / Microangiopathie thrombotique de novo post-transplantation rénale révélant un déficit en facteur H et en facteur I.

A 52-year-old man with an end stage renal failure of undetermined aetiology was hemodialysed in 2002. He received a cadaveric kidney transplantation in 2004. After an episode of diarrhea, a thrombotic microangiopathy was diagnosed in July 2009 and during this episode, a low C3 serum level was identified. Plasma exchanges were beneficial. Exploration of the low C3 serum level revealed both factor H and factor I deficiencies. We think that the renal failure of undetermined aetiology was probably an unnoticed haemolytic and uremic syndrome which recurred more than five years after transplantation.

Return to dialysis after renal allograft loss: is dialysis treatment initiated too late?

INTRODUCTION: Allograft failure is a common complication after renal transplantation. However, data describing the level of renal function and the clinical condition of patients returning to dialysis after graft failure are scarce. The purpose of this analysis was to retrospectively determine the stage of end-stage renal failure at dialysis initiation and the outcome during the first year of dialysis among patients who lost their grafts. METHODS: We analyzed deaths with a functioning graft and graft losses among patients transplanted in our center between January 1, 1994, and December 31, 2003. Weight, blood pressure, serum albumin, hemoglobin, phosphorus-calcium levels, and vascular access for dialysis were analyzed at the beginning (D(0)) and at 1 year after initiation of dialysis (M(12)). Creatinine clearance (CrCl), and hemoglobin were also studied at 3 months before beginning renal replacement therapy (M(-3)). RESULTS: Ninety-eight patients lost their grafts after a mean follow-up of 94 +/- 34 months; 37 died with a functioning graft and 61 returned to dialysis. Patient age was 62 +/- 10 years for the first group and 47 +/- 13 years for the second. At D(0), patients were hypertensive and anemic with a mean CrCl of 10 +/- 3 mL/min, suggesting that they were referred too late for dialysis. Surprisingly, at M(-3), CrCl was 19 +/- 7 mL/min and hemoglobin 10.6 +/- 3.6 g/dL. Four patients died during the first year of dialysis. CONCLUSIONS: Our data suggest that transplant patients returned to dialysis too late. CrCl and hemoglobin deteriorate rapidly during the 3 months preceding dialysis initiation.