Porto-sinusoidal vascular disorder and nephrotic-range proteinuria due to venous vasculitis in Behçet's disease.

Behçet's disease (BD) is an autoinflammatory disease with multifactorial and polygenic etiology, potentially involving arteries and veins of any size resulting in variable vessel vasculitis. We report a case of an Iranian male who presented with porto-sinusoidal vascular disorder due to venous vasculitis as initial manifestation of BD. Despite immunosuppression, anticoagulation and venous recanalization, he subsequently developed severe nephrotic-range proteinuria mimicking a primary renal disease which was completely and immediately ameliorated by stenting of the vena cava. This demonstrates that the proteinuria was caused by increased intraglomerular pressure due to venous outflow obstruction as a consequence of venous vasculitis. To our knowledge, this is the first report of massive proteinuria caused by venous obstruction of the caval vein in the context of BD. Altogether, this case demonstrates the extensive spectrum of vascular disease in BD.

Differential effects of donor-specific HLA antibodies in living versus deceased donor transplant.

The presence of donor-specific anti-HLA antibodies (DSAs) is associated with increased risk of graft failure after kidney transplant. We hypothesized that DSAs against HLA class I, class II, or both classes indicate a different risk for graft loss between deceased and living donor transplant. In this study, we investigated the impact of pretransplant DSAs, by using single antigen bead assays, on long-term graft survival in 3237 deceased and 1487 living donor kidney transplants with a negative complement-dependent crossmatch. In living donor transplants, we found a limited effect on graft survival of DSAs against class I or II antigens after transplant. Class I and II DSAs combined resulted in decreased 10-year graft survival (84% to 75%). In contrast, after deceased donor transplant, patients with class I or class II DSAs had a 10-year graft survival of 59% and 60%, respectively, both significantly lower than the survival for patients without DSAs (76%). The combination of class I and II DSAs resulted in a 10-year survival of 54% in deceased donor transplants. In conclusion, class I and II DSAs are a clear risk factor for graft loss in deceased donor transplants, while in living donor transplants, class I and II DSAs seem to be associated with an increased risk for graft failure, but this could not be assessed due to their low prevalence.

How can we reduce costs of solid-phase multiplex-bead assays used to determine anti-HLA antibodies?

Solid-phase multiplex-bead assays are widely used in transplantation to detect anti-human leukocyte antigen (HLA) antibodies. These assays enable high resolution detection of low levels of HLA antibodies. However, multiplex-bead assays are costly and yield variable measurements that limit the comparison of results between laboratories. In the context of a Dutch national Consortium study we aimed to determine the inter-assay and inter-machine variability of multiplex-bead assays, and we assessed how to reduce the assay reagents costs. Fifteen sera containing a variety of HLA antibodies were used yielding in total 7092 median fluorescence intensities (MFI) values. The inter-assay and inter-machine mean absolute relative differences (MARD) of the screening assay were 12% and 13%, respectively. The single antigen bead (SAB) inter-assay MARD was comparable, but showed a higher lot-to-lot variability. Reduction of screening assay reagents to 50% or 40% of manufacturers' recommendations resulted in MFI values comparable to 100% of the reagents, with an MARD of 12% or 14%, respectively. The MARD of the 50% and 40% SAB assay reagent reductions were 11% and 22%, respectively. From this study, we conclude that the reagents can be reliably reduced at least to 50% of manufacturers' recommendations with virtually no differences in HLA antibody assignments.

Virus-Specific CD8(+) T Cells Cross-Reactive to Donor-Alloantigen Are Transiently Present in the Circulation of Kidney Transplant Recipients Infected With CMV and/or EBV.

T cells play a dual role in transplantation: They mediate transplant rejection and are crucial for virus control. Memory T cells generated in response to pathogens can cross-react to alloantigen, a phenomenon called heterologous immunity. Virus-specific CD8(+) T cells cross-reacting to donor-alloantigen might affect alloimmune responses and hamper tolerance induction following transplantation. Here, we longitudinally studied these cross-reactive cells in peripheral blood of 25 kidney transplant recipients with a cytomegalovirus and/or Epstein-Barr virus infection. Cross-reactive T cells were identified by flow cytometry as virus-specific T cells that proliferate in response to donor cells in a mixed-lymphocyte reaction. In 13 of 25 patients, we found cross-reactivity to donor cells for at least 1 viral epitope before (n = 7) and/or after transplantation (n = 8). Cross-reactive T cells were transiently present in the circulation, and their precursor frequency did not increase following transplantation or viral infection. Cross-reactive T cells expressed interferon-γ and CD107a in response to both alloantigen and viral peptide and resembled virus-specific T cells in phenotype and function. Their presence was not associated with impaired renal function, proteinuria, or rejection. In conclusion, virus-specific T cells that cross-react to donor-alloantigen are transiently detectable in the circulation of kidney transplant recipients.

Hepcidin in chronic kidney disease: not an anaemia management tool, but promising as a cardiovascular biomarker.

Hepcidin is a key regulator of iron homeostasis and plays a role in the pathogenesis of anaemia of chronic disease. Its levels are increased in patients with chronic kidney disease (CKD) due to diminished renal clearance and an inflammatory state. Increased hepcidin levels in CKD patients are supposed to be responsible for functional iron deficiency in these patients and contribute to renal anaemia and resistance to erythropoiesis-stimulating agents. Therefore, hepcidin was purported to be useful as a management tool guiding treatment of renal anaemia. Furthermore, since hepcidin is associated with iron accumulation in macrophages in the vessel wall inducing oxidative stress and atherosclerosis, it has been speculated that hepcidin might function as a biomarker of cardiovascular disease. In this descriptive review, the merits of hepcidin with respect to its role in the pathophysiology of renal anaemia in CKD patients, its presumptive role as a practical diagnostic tool guiding management of renal anaemia, and its possible usefulness as a prognostic biomarker will be discussed.

The PROCARE consortium: toward an improved allocation strategy for kidney allografts.

Kidney transplantation is the best treatment option for patients with end-stage renal failure. At present, approximately 800 Dutch patients are registered on the active waiting list of Eurotransplant. The waiting time in the Netherlands for a kidney from a deceased donor is on average between 3 and 4 years. During this period, patients are fully dependent on dialysis, which replaces only partly the renal function, whereas the quality of life is limited. Mortality among patients on the waiting list is high. In order to increase the number of kidney donors, several initiatives have been undertaken by the Dutch Kidney Foundation including national calls for donor registration and providing information on organ donation and kidney transplantation. The aim of the national PROCARE consortium is to develop improved matching algorithms that will lead to a prolonged survival of transplanted donor kidneys and a reduced HLA immunization. The latter will positively affect the waiting time for a retransplantation. The present algorithm for allocation is among others based on matching for HLA antigens, which were originally defined by antibodies using serological typing techniques. However, several studies suggest that this algorithm needs adaptation and that other immune parameters which are currently not included may assist in improving graft survival rates. We will employ a multicenter-based evaluation on 5429 patients transplanted between 1995 and 2005 in the Netherlands. The association between key clinical endpoints and selected laboratory defined parameters will be examined, including Luminex-defined HLA antibody specificities, T and B cell epitopes recognized on the mismatched HLA antigens, non-HLA antibodies, and also polymorphisms in complement and Fc receptors functionally associated with effector functions of anti-graft antibodies. From these data, key parameters determining the success of kidney transplantation will be identified which will lead to the identification of additional parameters to be included in future matching algorithms aiming to extend survival of transplanted kidneys and to diminish HLA immunization. Computer simulation studies will reveal the number of patients having a direct benefit from improved matching, the effect on shortening of the waiting list, and the decrease in waiting time.

Abdominal wall phlebitis due to Prevotella bivia following renal transplantation in a patient with an occluded inferior vena cava.

Pre-existing occlusion of the inferior vena cava may complicate renal transplantation. Suppurative abdominal wall phlebitis following renal transplantation was diagnosed in a patient with pre-existing thrombosis of the inferior vena cava of unknown cause. The phlebitis developed in the subcutaneous collateral veins of the abdominal wall contra-laterally to the renal transplant. Cultures from abdominal wall micro-abscesses yielded Prevotella bivia as the causative agent. This complication has not been described before in the context of renal transplantation. The pathogenesis and management of this serious complication are discussed in this paper.

[Decreasing prevalence of Helicobacter pylori: a consequence of treatment of gastroduodenal ulcers]. / Dalende prevalentie van Helicobacter pylori: consequenties voor de behandeling van gastroduodenale ulcera.

Four patients with gastroduodenal ulcers in the absence of Helicobacter pylori illustrate the decreasing prevalence of this microorganism. One was a 19-year-old boy with nausea, diarrhoea and weight loss caused by multiple gastroduodenal ulcers due to the Zollinger-Ellison syndrome. Another was a 36-year-old man with abdominal discomfort caused by an ulcer due to Crohn's disease. The other two cases concerned a 29-year-old man and a 68-year-old woman with relapsing ulcer disease and active bleeding, in whom no causal factors could be determined. Recent studies suggest a decreasing prevalence of H. pylori leading to both a relative and an absolute decrease of gastroduodenal ulcers attributed to H. pylori. Future treatment strategies will have to take these altered prevalence rates into consideration.