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The effect of immunosuppressive drugs on the generation of T follicular helper (Tfh) cells, specialized in supporting B-cell differentiation, is largely unknown. We examined whether the calcineurin inhibitor tacrolimus (TAC) and the mammalian target of rapamycin (mtor) inhibitor sirolimus (SRL) inhibit Tfh cell differentiation, and affect subsequent B-cell functions. Isolated naive T cells were polarized into Tfh-like cells in the presence of TAC or SRL. To demonstrate their functionality, we co-cultured these cells with isolated B cells in the presence of alloantigen and studied the activation and differentiation of these B cells. Tfh-like cells were defined as CD4+CXCR5+ T cells, expressing immunoinhibitory programmed death protein 1 (pd1) and inducible T-cell costimulator (icos). We found that TAC and SRL significantly inhibited Tfh-like cell differentiation. Therapeutic concentrations of TAC and SRL reduced the percentage of pd1+ and icos+ Tfh cells compared to controls. In addition, T cells grown in the presence of TAC or SRL expressed less IL-21 and provided less B-cell help. TAC and SRL both inhibited Tfh-dependent alloantigen-activated B-cell proliferation and differentiation into plasma cells and transitional B cells. In conclusion, TAC and SRL inhibited the differentiation of naive T cells into functional Tfh-like cells, a finding that can be extrapolated to immunosuppressive regimens in transplant patients.

Background Therapeutic drug monitoring (TDM) of tacrolimus, based on blood concentrations, shows an imperfect correlation with the occurrence of rejection. Here, we tested whether measuring NFATc1 amplification, a member of the calcineurin pathway, is suitable for TDM of tacrolimus. Materials and methods NFATc1 amplification was monitored in T cells of kidney transplant recipients who received either tacrolimus- (n = 11) or belatacept-based (n = 10) therapy. Individual drug effects on NFATc1 amplification were studied in vitro, after spiking blood samples of healthy volunteers with either tacrolimus, belatacept or mycophenolate mofetil. Results At day 30 after transplantation, in tacrolimus-treated patients, NFATc1 amplification was inhibited in CD4+ T cells expressing the co-stimulation receptor CD28 (mean inhibition 37%; p = 0.01) and in CD8+CD28+ T cells (29% inhibition; p = 0.02), while this was not observed in CD8+CD28- T cells or belatacept-treated patients. Tacrolimus pre-dose concentrations of these patients correlated inversely with NFATc1 amplification in CD28+ T cells (rs = -0.46; p < 0.01). In vitro experiments revealed that 50 ng/ml tacrolimus affected NFATc1 amplification by 58% (mean; p = 0.02). Conclusion In conclusion, measuring NFATc1 amplification is a direct tool for monitoring biological effects of tacrolimus on T cells in whole blood samples of kidney transplant recipients. This technique has potential that requires further development before it can be applied in daily practice.

Pharmacokinetic immunosuppressive drug monitoring poorly correlates with clinical outcomes after solid organ transplantation. A promising method for pharmacodynamic monitoring of tacrolimus (TAC) in T cell sub

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Background: Monocytes significantly contribute to ischemia-reperfusion injury and allograft rejection after kidney transplantation. However, the knowledge about the effects of immunosuppressive drugs on monocyte activation is limited. Conventional pharmacokinetic methods for immunosuppressive drug monitoring are not cell type–specific. In this study, phosphorylation of 3 signaling proteins was measured to determine the pharmacodynamic effects of immunosuppression on monocyte activation in kidney transplant patients. Methods: Blood samples from 20 kidney transplant recipients were monitored before and during the first year after transplantation. All patients received induction therapy with basiliximab, followed by tacrolimus (TAC), mycophenolate mofetil, and prednisolone maintenance therapy. TAC whole-blood predose concentrations were determined using an antibody-conjugated magnetic immunoassay. Samples were stimulated with phorbol 12-myristate 13-acetate (PMA)/ionomycin, and phosphorylation of p38MAPK, ERK, and Akt in CD14+ monocytes was quantified by phospho-specific flow cytometry. Results: Phosphorylation of p38MAPK and Akt in monocytes of immunosuppressed recipients was lower after 360 days compared with before transplantation in the unstimulated samples [mean reduction in median fluorescence intensity 36%; range −28% to 77% for p-p38MAPK and 20%; range −22% to 53% for p-Akt; P < 0.05]. P-ERK was only decreased at day 4 after transplantation (mean inhibition 23%; range −52% to 73%; P < 0.05). At day 4, when the highest whole-blood predose TAC concentrations were measured, p-p38MAPK and p-Akt, but not p-ERK, correlated inversely with TAC (rs = −0.65; P = 0.01 and rs = −0.58; P = 0.03, respectively). Conclusions: Immunosuppressive drug combination therapy partially inhibits monocyte activation pathways after kidney transplantation. This inhibition can be determined by phospho-specific flow cytometry, which enables the assessment of the pharmacodynamic effects of i

Item does not contain fulltext, Acute rejection is one of the major immunological determinants of kidney graft function and survival. Early biomarkers to predict rejection are lacking. Emerging evidence reveals a crucial role for the monocyte/macrophage lineage cells in the pathogenesis of rejection. We hypothesized that higher pretransplant numbers of proinflammatory CD16+ monocytes can predict rejection. The study cohort consisted of 104 kidney transplant recipients (58 with no rejection and 46 with biopsy-proven rejection) and 33 healthy persons. Posttransplant median follow-up time was 14.7 mo (interquartile range 0.3-34 mo). Pretransplantation blood samples were analyzed by flow cytometry for monocyte immunophenotypes. Groups were compared by Cox regression models for the occurrence of acute rejection. We documented a significantly increased absolute number of pretransplant CD16+ monocytes in patients who developed biopsy-proven rejection after transplantation compared with those with no rejection (hazard ratio [HR] 1.60, 95% CI 1.28-2.00, p < 0.001) and healthy persons (HR 1.47, 95% CI 1.18-1.82, p < 0.001). In parallel, significantly fewer absolute numbers of CD16- monocytes were observed at pretransplant time points in rejectors versus nonrejectors (HR 0.74, 95% CI 0.58-0.94, p < 0,014). A higher pretransplant number of CD16+ monocytes is significantly associated with a higher risk of acute rejection after kidney transplantation.

Holwerd aan Zee is een dorp in Friesland dat bij veel mensen bekend staat als dorp op weg naar Ameland. Holwerd wil van dit imago af en wil graag meer bezoekers en wellicht inwoners die naar het dorp komen voor een vakantie of een dagje weg. Om hiervoor een oplossing te vinden is een benchmark gemaakt met het dorp Ouddorp op Goeree – Overflakkee. Dit is het eiland wat hoort bij de provincie Zuid – Holland en wat vooral bekend staat om de verschillende watersport locaties en het natuurgebied Tiengemeten.

Om de krimp van Holwerd tegen te gaan en het gebied tegelijkertijd aantrekkelijker te maken voor toerisme is er een toekomstvisie uitgewerkt voor Holwerd. Hier zijn de drie V’s (Vervoer, Verblijf en Vermaak) en de drie P’s (People, Planet en Profit) voor uitgewerkt. Deze zijn vervolgens tegen over elkaar gezet in een matrix om te verduidelijken hoe dit wordt toegepast in Holwerd.

Summary: Memory B cells play a pivotal role in alloreactivity in kidney transplantation. Follicular T helper (Tfh) cells play an important role in the differentiation of B cells into immunoglobulin-producing plasmablasts [through interleukin (IL)-21]. It is unclear to what extent this T cell subset regulates humoral alloreactivity in kidney transplant patients, therefore we investigated the absolute numbers and function of peripheral Tfh cells (CD4POSCXCR5POS T cells) in patients before and after transplantation. In addition, we studied their relationship with the presence of donor-specific anti-human leucocyte antigen (HLA) antibodies (DSA), and the presence of Tfh cells in rejection biopsies. After transplantation peripheral Tfh cell numbers remained stable

Rabbit anti-thymocyte globulins (rATG) induce CD4+CD25 +forkhead box P3 (FoxP3+) regulatory T cells that control alloreactivity. In the present study, we investigated whether rATG convert T cells into functional CD4+CD25+FoxP3+CD127 -/low regulatory T cells in the presence of drugs that may hamper their induction and function, i.e. calcineurin inhibitors. CD25neg T cells were stimulated with rATG or control rabbit immunoglobulin G (rIgG) in the absence and presence of tacrolimus for 24 h. Flow cytometry was performed for CD4, CD25, FoxP3 and CD127 and the function of CD25+ T

The ongoing erosion of the Negril Beach has become worse the past decade. In most places along the coast line, the beach will be gone in approximately 10 years. This will result in a major decrease of incomes that are made by the local tourist sector. To prevent the erosion this study has been performed to find a feasible and affordable solution. An important part of the study is the literature research since several other parties had investigated different aspects of the erosion problem recently. Before any solutions can be brought up different aspects have to be investigated. These are a clear view of the actual problem, a good knowledge of the environment, profiles of the coastline, current patterns and sea grass locations to avoid environmental damage as much as possible. Data was collected during two field trips to Negril in the end of 2006. After collecting this data an analysis was made using different computer models as LITPACK (sediment transport), SWAN (waves) and RMA (currents). The data analysis shows that the primary concern is the erosion at Long Bay since the erosion in Bloody Bay is not that severe. Possible solutions are generated and their validity has been checked. Five alternatives can be distinguished: zero-alternative, nourishment, series of near-shore breakwaters, off shore reef extension and a combination of all. Using a Multi Criteria Analyses (MCA), that ranks solutions by their desired effects (without including costs), objectively the 'best' solution is found. The solution that scores best at our criteria is beach nourishment along Long Bay. When costs are taken into account, this solution seems to be the most efficient. Costs are estimated US$7,000,000. The final recommendation is to execute beach nourishment only at Long Bay. This solution is relatively affordable and shows the highest score in the MCA. The implementation of this solution results in a minimum beach width of about 10 meters for 20 years, about 30 meters in the year of ex, Hydraulic Engineering, Civil Engineering and Geosciences

R. Kraaijeveld Laagland. Globe: literatuur voor de tweede fase, Nederlands. VWO informatie- en verwerkingsboek. En: Laagland Literatuur Nederlands voor de tweede fase. HAVO informatie- en verwerkingsboek Zutphen:Thieme ,1999 90 03 23510 4, Item does not contain fulltext