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.

Female urothelial cell carcinoma in a failed kidney graft of a male recipient.

We present a case of a male kidney transplant patient harbouring two kidney grafts of which one is functional. In the failed graft, he developed urothelial cell carcinoma with cells containing XX-chromosome, and female tumour cells were also found in the bladder. The patient underwent donor nephrectomy, was treated with epirubicin bladder instillations, and immunosuppression was tapered. Less than a year before re-transplantation a CT scan showed no abnormalities of the first graft. Transplantectomy before a second kidney transplantation is debated.

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.

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.

The Maastricht Transplant Center: clinical setting and epitope searches in HLA class II molecules: does the structural localization of a polymorphic site contribute to its immunogenicity?

Our understanding of the immunological processes influencing the clinical outcome after kidney transplantation has advanced majorly over the last few decades. However, many factors still restrict graft and patient survival. Within the Maastricht transplant center we have successfully implemented an alternative immunosuppressive regimen involving Tacrolimus monotherapy in order to minimize the adverse effects associated with long-term use of immunosuppressive drugs. This clinical development has an impact on pre-transplant risk stratification which requires that patients are closely monitored immunologically. In this review we will elaborate on our strategy regarding the analysis of epitopes in HLA-DQ and HLA-DP molecules. In this respect we have also looked at the immunodominance of certain epitopes by assessing their structural localization, conformation and physiochemical properties.

Harmonization of description and classification of fetal observations: achievements and problems still unresolved: report of the 7th Workshop on the Terminology in Developmental Toxicology Berlin, 4-6 May 2011.

This article summarizes the 7th Workshop on the Terminology in Developmental Toxicology held in Berlin, May 4-6, 2011. The series of Berlin Workshops has been mainly concerned with the harmonization of terminology and classification of fetal anomalies in developmental toxicity studies. The main topics of the 7th Workshop were knowledge on the fate of anomalies after birth, use of Version 2 terminology for maternal-fetal observations and non-routinely used species, reclassification of "grey zone" anomalies and categorization of fetal observations for human health risk assessment. The paucity of data on health consequences of the postnatal permanence of fetal anomalies is relevant and further studies are needed. The Version 2 terminology is an important step forward and the terms listed in this glossary are considered also to be appropriate for most observations in non-routinely used species. Continuation of the Berlin Workshops was recommended. Topics suggested for the next Workshop were grouping of fetal observations for reporting and statistical analysis.

Preservation of renal function and cardiovascular risk factors.

An update is given about some factors leading to loss of renal allograft, especially in relation to the use of tacrolimus and cyclosporine. We discuss both immunological, such as suboptimal immunosuppression, acute rejection, and noncompliance, as well as nonimmunological factor's such as hypertension, hyperlipidemia, chronic toxic effects of immunosuppressants, older donors, and delayed graft function.

Harmonization of rat fetal external and visceral terminology and classification. Report of the Fourth Workshop on the Terminology in Developmental Toxicology, Berlin, 18-20 April 2002.

This article is a report on the Fourth Berlin Workshop on Terminology in Developmental Toxicology, which was held in April 2002. The workshop is part of an international project in the field of harmonization of terminology in developmental toxicology supported by IPCS. The goal of the Harmonization Project is to ensure better chemical risk assessment. The aim of this Fourth Workshop was to discuss the results of a previously conducted survey on classification of external and visceral anomalies, which are listed in the international glossary, developed under the auspices of IFTS (1997 glossary). The discussions among experts from research institutions, regulatory agencies, and industries were mainly focussed on terms for which there was disagreement and/or uncertainties and the possible reasons. For the illustration of "gray-zone" anomalies, pictures were provided by the participants, which constituted the basis for detailed discussions. There was high agreement that most of the external anomalies (>66%) should be classified as malformations. The few external anomalies for which there was low agreement to classify as a malformation were discussed in detail. None of the external findings, which had in the survey a high agreement, were categorized as a variation.A high agreement regarding the classification of approximately one-third of visceral anomalies was achieved with 34 and 2% being described as malformation and variation, respectively. Most of the visceral findings had low agreement indices and there appeared to be several reasons for this. Thus, the response, 'Not known/not used in the laboratory' (N) was often given. A couple of reasons for difficulties in the classification of an anomaly were that it is only rarely seen upon fetal examination or tends to be species specific. Furthermore, the classification of some anomalies as malformation or variation will remain vague as the decision must be made on a case-by-case basis. Factors affecting the decision include: the availability of appropriate historical control data, description of the grading and severity, whether the anomaly occurs in isolation or whether there is a relationship with an abnormal process, and finally, if the change represents an irreversible one, affecting human and/or animal health. It was concluded that a severity grading, supported by pictures of the anomaly, would be especially helpful to classify certain changes as malformation or as variation. Several of the soft tissue changes were considered likely to be the consequence of functional disorders and thus not strictly developmental anomalies. The possibility to describe a finding as 'Not Malformation' (Unclassified) was agreed upon. As a general conclusion it was emphasized that the observation of a permanent structural change should be considered to be a warning of possible consequences to humans, even when there is no apparent adverse effect on health and survival in adult animals of the species under investigation. Therefore, research is needed to further investigate postnatal consequences. Future collaboration in the field of reproductive and developmental toxicology should aim to further develop and implement a harmonized approach to the interpretation of study data. Therefore, this terminology work will continue in close cooperation with the IPCS Harmonization Project. A Steering Group should be established to facilitate the implementation of harmonized terminology into daily scientific work and its regulatory application.

Metabolic aspects of tacrolimus in renal transplantation. Consequences for the choice of an immunosuppressive regimen and for the management of post-transplant diabetes mellitus.

The occurrence of post-transplant diabetes mellitus (PTDM) is an important complication after renal transplantation associated with an increased risk of chronic transplant dysfunction and of cardiovascular morbidity and mortality. Both tacrolimus and cyclosporine have been associated with PTDM. In the initial studies, PTDM seemed to occur more often in tacrolimus treated patients than in cyclosporine treated patients. The mechanism by which tacrolimus could cause PTDM was unknown and the relative roles of tacrolimus and corticosteroids, which are often prescribed concomitantly with tacrolimus, were unknown. In several studies we used fasting glucose and insulin levels to assess (peripheral) insulin resistance, and intravenous glucose tolerance tests to assess insulin secretion by the pancreatic b-cells in response to a stimulus (glucose load). Thus, we evaluated the mechanism by which tacrolimus causes glucose metabolic disorders, risk factors for glucose metabolic disorders during tacrolimus treatment, the relative roles of corticosteroids and tacrolimus trough levels in glucose metabolic disorders, and also differences in glucose metabolism between patients using tacrolimus versus patients using cyclosporine. Based on the results of these studies and the available literature, the consequences for the choice of a primary immunosuppressive agent and guidelines for the treatment of PTDM during tacrolimus-based immunosuppression are discussed.

Single-center experience with tacrolimus versus cyclosporine-Neoral in renal transplant recipients.

Tacrolimus has proven to be superior to cyclosporine-Sandimmune with regard to the prevention of acute rejections, but data comparing tacrolimus with Neoral are scarce. A total of 128 consecutive renal transplant recipients was studied. The patients were treated with Neoral-based (n = 74) or tacrolimus-based (n = 54) immunosuppressive regimens. Survival analyses (Cox regression analysis) were performed on an intention-to-treat basis. Renal function and cardiovascular risk profile were analyzed by means of a repeated-measures analysis of variance (ANOVA) up to 12 months after transplantation. Immunological features were less favorable in the tacrolimus group. Two-year patient and graft survival were comparable. Acute-rejection-free survival was 82 % in the tacrolimus group versus 40 % in the Neoral group (P < 0.0001). The severity of the rejections (1997 Banff classification) was comparable (P = 0.43). Immunological graft loss (3.7 % vs. 12.2 %, P = 0.02) and conversion because of rejection (0 % vs. 28.4 %, P < 0.001) were less in the tacrolimus group. A higher proportion (68.5 % vs. 14.9 %, P < 0.001) was successfully put on monotherapy. Creatinine clearance, proteinuria, and fractional uric acid clearance were similar. In the tacrolimus group mean blood pressure was comparable, but patients needed less anti-hypertensive drugs (P < 0.001) and, even with fewer patients on lipid-lowering drugs, total cholesterol was lower (5.2 vs. 6.0 mmol/l, P = 0.003). Treatment for post-transplant diabetes mellitus was 18.5 % versus 10.8 % (P = 0.22). In both groups, antidiabetic medication could be withdrawn for most patients. This study indicates that tacrolimus is superior to cyclosporine-Neoral in preventing acute rejection with comparable patient and graft survival rates. Because of a lower need for treatment of hypertension and hypercholesterolemia, the cardiovascular risk profile is more favorable. A considerable proportion of patients can be successfully weaned off co-medication and treated with tacrolimus monotherapy.

Lung and gastric uptake in bone scintigraphy of sarcoidosis.

We report on 99mTc-MDP uptake in lungs and stomach in a patient with hypercalcaemia and renal failure due to elevated 1,25(OH)2vitD3 because of sarcoidosis. Presently, this typical scan pattern has only been described in patients with malignancies, parathyroid adenoma and drug-induced vitamin D intoxication. We offer possible explanations for the findings in our patient.

[Postinfectious tropical malabsorption and the differences from non-tropical sprue (celiac disease)]. / Postinfectieuze tropische malabsorptie en de verschillen met niet-tropische spruw (coeliakie).

The clinical course is described of a 69-year-old patient with a malabsorption syndrome since her stay in Indonesia. Besides chronic diarrhoea and weight loss she suffered from malnutrition and had partial villous atrophy. Coeliac disease was considered in the differential diagnosis but considering the endemic appearance of postinfectious tropical sprue (PTS) in Indonesia and the extreme vitamin B12 deficiency our patient experienced, PTS appeared more likely. A good response to the therapy prescribed for PTS confirmed the diagnosis.