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Contains fulltext : 69863.pdf (Publisher’s version ) (Open Access) BACKGROUND: Transplant patients would benefit from reduction of immunosuppression providing that graft rejection is prevented. We have evaluated a number of immunological markers in blood of patients in whom tacrolimus was withdrawn after renal transplantation. The alloreactive precursor frequency of CD4+ and CD8+ T cells, the frequency of T cell subsets and the functional capacity of CD4+CD25+FoxP3+ regulatory T cells (Treg) were analyzed before transplantation and before tacrolimus reduction. In a case-control design, the results were compared between patients with (n = 15) and without (n = 28) acute rejection after tacrolimus withdrawal. PRINCIPAL FINDINGS: Prior to tacrolimus reduction, the ratio between memory CD8+ T cells and Treg was higher in rejectors compared to non-rejectors. Rejectors also had a higher ratio between memory CD4+ T cells and Treg, and ratios

Contains fulltext : 71444.pdf (Publisher’s version ) (Closed access) OBJECTIVE: The pharmacokinetics of mycophenolic acid (MPA) were compared in renal transplant patients receiving either mycophenolate mofetil (MMF) or enteric-coated mycophenolate sodium (EC-MPS). METHODS: MPA concentration-time profiles were included from EC-MPS- (n = 208) and MMF-treated (n = 184) patients 4-257 months after renal transplantation. Population pharmacokinetic analysis was performed using nonlinear mixed-effects modelling (NONMEM). A two-compartment model with first-order absorption and elimination was used to describe the data. RESULTS: No differences were detected in MPA clearance, intercompartmental clearance, or the central or peripheral volume of distribution. Respective values and interindividual variability (IIV) were 16 L/h (39%), 22 L/h (78%), 40 L (100%) and 518 L (490%). EC-MPS was absorbed more slowly than MMF with respective absorption rate constant values of 3.0 h(-1) and 4.1 h(-1) (p < 0.001) [IIV 187%]. A mixture model was used for the change-point parameter lag-time (t(lag)) in order to describe IIV in this parameter adequately for EC-MPS. Following the morning dose of EC-MPS, the t(lag) values were 0.95, 1.88 and 4.83 h for 51%, 32% and 17% of the population (IIV 8%), respectively. The morning t(lag) following EC-MPS administration was significantly different from both the t(lag) following MMF administration (0.30 h; p < 0.001 [IIV 11%]) and the t(lag) following the evening dose of EC-MPS (9.04 h; p < 0.001 [IIV 40%]). Post hoc analysis showed that the t(lag) was longer and more variable following EC-MPS administration (morning median 2.0 h [0.9-5.5 h], evening median 8.9 h [5.4-12.3 h]) than following MMF administration (median 0.30 h [0.26-0.34 h]; p < 0.001). The morning MPA predose concentrations were higher and more variable following EC-MPS administration than following MMF administration, with respective values of 2.6 mg/L (0.4-24.4 mg/L) and 1.6 mg/L (0.2-7.6 mg/L). The correlation between predose concentrations and the area under the plasma concentration-time curve (AUC) was lower in EC-MPS-treated patients (r(2) = 0.02) than in MMF-treated patients (r(2) = 0.48). CONCLUSION: Absorption of MPA was delayed and also slower following EC-MPS administration than following MMF administration. Furthermore, the t(lag) varied more in EC-MPS-treated patients. MPA predose concentrations were poorly correlated with the MPA AUC in both MMF- and EC-MPS-treated patients.

Contains fulltext : 70294.pdf ( ) (Open Access) BACKGROUND: Regulatory T cell (Treg) based immunotherapy is a potential treatment for several immune disorders. By now, this approach proved successful in preclinical animal transplantation and auto-immunity models. In these models the success of Treg based immunotherapy crucially depends on the antigen-specificity of the infused Treg population. For the human setting, information is lacking on how to generate Treg with direct antigen-specificity ex vivo to be used for immunotherapy. METHODOLOGY/PRINCIPAL FINDINGS: Here, we demonstrate that in as little as two stimulation cycles with HLA mismatched allogeneic stimulator cells and T cell growth factors a very high degree of alloantigen-specificity was reached in magnetic bead isolated human CD4(pos)CD25(high) Treg. Efficient increases in cell numbers were obtained. Primary allogeneic stimulation appeared a prerequisite in the generation of alloantigen-specific Treg, while secondary allogeneic or polyclonal stimulation with anti-CD3 plus anti-CD28 monoclonal antibodies enriched alloantigen-specificity and cell yield to a similar extent. CONCLUSIONS/SIGNIFICANCE: The ex vivo expansion protocol that we describe will very likely increase the success of clinical Treg-based immunotherapy, and will help to induce tolerance to selected antigens, while minimizing general immune suppression. This approach is of particular interest for recipients of HLA mismatched transplants.

Contains fulltext : 52757.pdf (Publisher’s version ) (Closed access) Graft-versus-host-disease (GVHD) is the most common cause of poor outcome after allogeneic stem cell transplantation (SCT). Of late, exploitation of FOXP3(+) regulatory T-cell (T(REG)) function is emerging as a promising strategy in suppression of GVHD, while preserving graft-versus-leukemia (GVL). Cyclosporine and rapamycin reduce the expansion of effector T cells by blocking interleukin (IL)-2, but signaling by IL-2 is pivotal for T(REG) homeostasis. The resolution of GVHD is critically dependent on thymus-dependent reconstitution of the immunoregulatory system. Thus, there has been concern about the impact of blocking IL-2 signaling by immunosuppressive agents on T(REG) homeostasis. Here we demonstrate in a mouse model that in contrast to rapamycin, cyclosporine compromises not only the thymic generation of CD4(+)CD25(+)FoxP3(+) T cells but also their homeostatic behavior in peripheral immune compartments. Treatment with cyclosporine resulted in a sharp reduction of peripheral CD25(+)FoxP3(+) T cells in all immune compartments studied. Prolonged rapamycin treatment allowed for thymic generation of CD4(+)FoxP3(+) T cells, whereas treatment with cyclosporine led to a reduced generation of these cells. In conclusion, cyclosporine and rapamycin differentially affect homeostasis of CD4(+)FoxP3(+) T(REG) in vivo. As peripheral tolerance induction is a prerequisite for successful treatment outcome after allogeneic SCT, these findings are of potential clinical relevance.

Contains fulltext : 52012.pdf (Publisher’s version ) (Closed access) BACKGROUND: The identification of transplant patients at high risk for rejection after reduction of immunosuppression would allow minimization of immunosuppression and avoidance of side effects in low-risk patients. Next to T cells, innate natural killer (NK) cells may contribute to graft rejection. NK cell activation depends on the balance between activating and inhibitory signals, delivered by self-human leukocyte antigens (HLA) through binding of killer-cell immunoglobulin receptors (KIR). In transplantation, KIR and/or HLA mismatching may lead to NK cell activation. METHODS: In this study, we have evaluated whether acute rejection after reduction of immunosuppression after renal transplantation was associated with peripheral blood NK cell frequencies or with predicted NK cell alloreactivity based on KIR gene and ligand analysis. HLA and KIR genotyping was used to analyze the presence of single KIR genes and haplotypes, and to predict NK cell alloreactivity based on the "missing self" and "missing ligand" hypothesis. NK cell frequencies were analyzed using flow cytometry. RESULTS: No association was found between NK cell alloreactivity based on KIR gene analysis or peripheral blood NK cell subset frequencies and the occurrence of acute rejection after reduction of immunosuppression. CONCLUSIONS: Our data suggest that in a setting where immunosuppression is reduced, prior analysis of NK cell reactivity cannot identify patients at risk for subsequent graft rejection.

Contains fulltext : 51465.pdf (Publisher’s version ) (Closed access) The induction of transplantation tolerance involves a T-cell-mediated process of immune regulation. In clinical transplantation, the use of immunosuppressive drugs that promote or facilitate this process would be highly desirable. Here, we investigated the tolerance-promoting potential of the immunosuppressive drug FK778, currently under development for clinical therapy. Using a human allogeneic in vitro model we showed that, upon T-cell receptor (TCR) triggering, FK778 induced a regulatory phenotype in CD4+ CD25- T cells. Purified CD4+ CD25- T cells primed in the presence of FK778 showed hyporesponsiveness upon restimulation with alloantigen in the absence of the drug. This anergic state was reversible by exogenous interleukin-2 (IL-2) and was induced independent of naturally occurring CD4+ CD25+ regulatory T cells. Pyrimidine restriction was a crucial requirement for the de novo induction of regulatory activity by FK778. The FK778-induced anergic cells showed suppressor activity in a cell-cell contact-dependent manner; were CD25(high), CD45RO+, CD27-, and CD62L-; and expressed cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4), glucocorticoid-induced tumor necrosis factor receptor (GITR), and FoxP3. The cells revealed delayed p27(kip1) degradation and enhanced phosphorylation of STAT3. In conclusion, the new drug FK778 shows tolerizing potential through the induction of a regulatory T-cell subset in CD4+ CD25- T cells.

Contains fulltext : 53537.pdf (Publisher’s version ) (Closed access) Current therapies in transplantation require continuous immunosuppression and do not result in transplantation tolerance. It is increasingly appreciated that CD4(+)CD25(+) regulatory T-cell (T(REG)) activation is pivotal for the induction and maintenance of peripheral tolerance. To optimally exploit T(REG) in allograft tolerance, we investigated how to further harness their function. In vitro, CD4(+)CD25(+)T cells were expanded by allogeneic bone-marrow derived DC or polyclonal stimulation and were compared in suppressive capacity and phenotype. In vivo, naive allogeneic CD4(+)CD25(+)T cells were analyzed in wild type hosts for proliferative capacity and suppressive capacity upon priming by alloantigen. DC of donor origin were found to potently stimulate alloreactive T(REG)in vitro. This was accompanied by a substantial enhancement of the suppressive capacity of the T(REG) population as a whole, likely due to a proportional rise of alloreactive T(REG) as indicated by CFSE analysis. In vivo analysis of infused naturally occurring allogeneic T(REG) revealed a robust proliferative capacity for T(REG) upon stimulation. Moreover, allogeneic skin transplantation resulted in enhanced capacity of the T(REG) population to suppress the response towards donor antigens. Combining, activation of alloreactive T(REG) is an intrinsic part of the regular alloimmune response and this feature can be exploited for therapeutic purposes. We propose that selectively favoring the effects of alloreactive T(REG) is a pivotal element in inducing graft acceptance.

Daclizumab, a humanized antibody directed against the alpha-chain of the interleukin-2 receptor (CD25), has shown efficacy in the prevention of acute rejection following organ transplantation. However, anti-CD25 therapy can be expected to affect not only alloreactive effector T cells, but also CD4(+)CD25(+) regulatory T (Treg) cells that are shown to play an important role in the induction of transplantation tolerance. Therefore, the size and function of the Treg pool in human renal allograft recipients after single-dose daclizumab administration was investigated in this study. Approximately 8 weeks after administration, daclizumab was cleared from the circulation and the Treg population then present appeared not different from that observed before transplantation. Functional analysis revealed that the Treg possessed a normal capacity to suppress mixed lymphocyte reactions in vitro. These data indicate that after daclizumab therapy a Treg population, normal in number and function, is present in the peripheral blood of renal transplant recipients.

Contains fulltext : 49881.pdf (Publisher’s version ) (Closed access) Regulatory T cell (Treg) function is associated with immune tolerance and could serve as a biomarker for optimization of immunosuppressive regimens. This is hampered by the limited number of Treg in the blood circulation; functional Treg analysis requires large volumes of blood or is dependent on indirect analysis. A more attractive strategy is the ex vivo expansion of Treg, provided the original T cell pool remains unaltered. Here, we show that it is possible to ex vivo expand Treg from limited amounts of blood, preserving the original TCR Vbeta repertoire and suppressive capacity. The protocol proved successful in selected renal transplant recipients and leukopenic patients. Sampling of 10-20 ml blood sufficed; Treg numbers increased over 100-fold during the 2-3 week expansion period, easily reaching cell numbers required for functional analysis (>10(6) cells). This protocol will facilitate the monitoring of Treg function in patients in order to address the role of Treg in transplantation tolerance.

Contains fulltext : 50349.pdf (Publisher’s version ) (Closed access) The immunosuppressive drugs rapamycin and cyclosporin A (CsA) are widely used to prevent allograft rejection. Moreover, they were shown to be instrumental in experimental models of tolerance induction. However, it remains to be elucidated whether these drugs have an effect on the CD4+ CD25+ regulatory T-cell (T(REG)) population, which plays an important role in allograft tolerance. Recently, we reported that alloantigen-driven expansion of human CD4+ CD25+ T(REG)s gives rise to a distinct highly suppressive CD27+ T(REG) subset next to a moderately suppressive CD27- T(REG) subset. In the current study we found that rapamycin and CsA do not interfere with the suppressive activity of human naturally occurring CD4+ CD25+ T cells. However, in contrast to CsA, rapamycin preserved the dominance of the potent CD27+ T(REG) subset over the CD27- T(REG) subset after alloantigen-driven expansion of CD4+ CD25+ T(REG)s in vitro. Accordingly, CD4+ CD25+ T(REG)s cultured in the presence of rapamycin displayed much stronger suppressive capacity than CD4+ CD25+ T(REG)s cultured in the presence of CsA. In addition, CD4+ CD25+ T(REG) cells cultured in the presence of rapamycin, but not CsA, were able to suppress ongoing alloimmune responses. This differential effect of rapamycin and CsA on the CD27+ T(REG) subset dominance may favor the use of rapamycin in tolerance-inducing strategies.

Contains fulltext : 47700.pdf (Publisher’s version ) (Closed access) BACKGROUND: Clinical tolerance is the net result of regulatory and effector functions. In this article, the authors show that tolerance induction by co-stimulation blockade preferentially works through CD4CD25 regulatory T-cell-mediated suppression that is effectively achieved by selective reduction of the effector T-cell load. Anti-CD86 and anti-CD40L monoclonal antibody treatment during in vitro mixed lymphocyte reaction (MLR) typically results in the induction of a suppressive polyclonal T-cell population. This induced suppressive capacity was found to be dependent on the presence of CD4CD25 T cells at the start of MLR. METHODS: Using a CFSE-based strategy, the authors show that within the polyclonal T-cell population, the suppressive effect was exerted by a nondividing CD4CD25 T-cell subset. RESULTS: The cells exclusively originated from preexisting CD4CD25 regulatory T cells and proved anergic and highly suppressive on isolation. They carried the CD45RB and CD62L phenotype and expressed GITR. There was no indication of de novo induction of regulatory T cells by co-stimulation blockers. Instead, the authors observed, both in vitro and in vivo, that co-stimulation blockade shifted the ratio between alloreactive effectors and regulatory T cells in favor of the latter. CONCLUSION: The authors therefore conclude that co-stimulation blockade contributes to functional dominance of regulatory T cells by preventing expansion of alloreactive effector T cells. Tolerance-inducing protocols should ideally facilitate this phenomenon.

Contains fulltext : 47485.pdf (Publisher’s version ) (Open Access)

Steroid-related bone loss is a recognized complication after renal transplantation. In a prospective, randomized, multicenter study we compared the influence of a steroid-free immunosuppressive regimen with a regimen with limited steroid exposure on the changes in bone mass after renal transplantation.A total of 364 recipients of a renal transplant were randomized to receive either daclizumab (1 mg/kg on days 0 and 10 after transplantation; steroid-free group n=186) or prednisone (0.3 mg/kg per day tapered to 0 mg at week 16 after transplantation; steroids group n=178). All patients received tacrolimus, mycophenolate mofetil, and, during the first 3 days, 100 mg prednisolone intravenously. Changes in bone mineral density (BMD) were evaluated in 135 and 126 patients in the steroid-free and steroids group, respectively.The mean (+/- SD) BMD of the lumbar spine decreased slightly in both groups during the first 3 months after transplantation (steroid-free -1.3 +/- 4.0% [P0.01]; steroids -2.3 +/-4.2% [P0.01]). In the following months, lumbar BMD recovered in both groups (P0.01), resulting in a lumbar BMD at 12 months after transplantation comparable with the baseline value. No difference between the groups was found at 3 months (steroid-free versus steroids +1.0%; 95% confidence interval -0.0%-+2.0%, P=0.060) and at 12 months after transplantation (steroid-free versus steroids +0.9%; 95% confidence interval -0.8%-+2.6%, NS).The use of a moderate dose of steroids during 4 months after transplantation has no important influence on bone mass during the first year after renal transplantation. On average, both regimens prevented accelerated bone loss.

Contains fulltext : 57494.pdf (Publisher’s version ) (Closed access) BACKGROUND: Chronic allograft nephropathy (CAN) is the leading cause of late allograft failure, with only limited treatment options. Blockade of the renin-angiotensin system (RAS) decreases progression in diabetic and non-diabetic renal disease, but the effect on CAN is as yet unclear. Therefore, we have studied retrospectively the effect of RAS blockade on renal survival in patients with biopsy-proven CAN. METHODS: The medical records of 72 patients with biopsy-proven CAN were evaluated with regard to time course of graft function, proteinuria, blood pressure, and antihypertensive and immunosuppressive treatment. Cox's proportional hazards model was used for analysing renal graft survival after the index biopsy. RESULTS: On univariate analysis, histological determinants influencing renal survival were the chronic interstitial and chronic tubular score, and clinical parameters were the serum creatinine level at the time of the biopsy, the relative change in serum creatinine level between 12 months post-transplantation and at the time of the biopsy, mean systolic and diastolic blood pressure after the biopsy, and RAS blockade by angiotensin-converting enzyme inhibitor or angiotensin receptor blocker. On multivariate analysis, graft outcome was influenced by the relative change in serum creatinine level between 12 months post-transplantation and the time of the index biopsy, the urinary protein excretion, the mean diastolic blood pressure after the index biopsy, and RAS blockade. Renal graft survival after treatment with RAS blockade was 6.3 (0.9-10.9) years as opposed to 1.8 (0.1-6.7) years in untreated patients (P = 0.003). CONCLUSION: RAS blockade increases graft survival in CAN. In view of the limited treatment options for CAN, this finding is of importance and needs confirmation by a prospective randomized trial.

Steroid-withdrawal at 3 days after renal transplantation with anti-IL-2 receptor alpha therapy: a prospective, randomized, multicenter study.ter Meulen CG, van Riemsdijk I, Hene RJ, Christiaans MH, Borm GF, van Gelder T, Hilbrands LB, Weimar W, Hoitsma AJ.Department of Internal Medicine, Division of Nephrology, University Medical Center Nijmegen, Nijmegen, the Netherlands. C.Termeulen@nier.umcn.nlSteroids have been included in most immunosuppressive regimens after renal transplantation, but are feared for their side-effects. We conducted a prospective multicenter study to investigate whether it is feasible to withdraw steroids early after transplantation with the use of anti-IL-2Ralpha induction, tacrolimus and mycophenolate mofetil (MMF). A total of 364 patients were randomized to receive either two doses of daclizumab (1 mg/kg) and, for the first 3 days, 100 mg of prednisolone (daclizumab group n = 186), or steroids (tapered to 0 mg at week 16; controls n = 178). All patients received tacrolimus and MMF. The incidence of biopsy-confirmed acute rejection at 12 months was not different between the daclizumab group (15%) and the controls (14%) (95% confidence interval of difference: -6 to + 8%, NS). Graft survival at 12 months was comparable in the two groups (daclizumab group: 91%; controls: 90%). Mean arterial blood pressure, serum lipids, and incidence of patients with hyperglycemia were temporary lower in the daclizumab group compared with controls. The immunosuppressive regimen of the daclizumab group was associated with increased costs. In conclusion, with the use of anti-IL-2Ra induction and daily therapy with tacrolimus and MMF it is feasible to withdraw steroids at 3 days after renal transplantation.

Conversion from cyclosporine to tacrolimus improves quality-of-life indices, renal graft function and cardiovascular risk profile.Artz MA, Boots JM, Ligtenberg G, Roodnat JI, Christiaans MH, Vos PF, Moons P, Borm G, Hilbrands LB.Department of Nephrology, University Medical Centre of Nijmegen, the Netherlands. m.artz@nier.umcn.nlLong-term use of cyclosporine after renal transplantation results in nephrotoxicity and an increased cardiovascular risk profile. Tacrolimus may be more favorable in this respect. In this randomized controlled study in 124 renal transplant patients, the effects of conversion from cyclosporine to tacrolimus on renal function, cardiovascular risk factors, and perceived side-effects were investigated after a follow-up of 2 years. After conversion from cyclosporine to tacrolimus renal function remained stable, whereas continuation of cyclosporine was accompanied by a rise in serum creatinine from 142 +/- 48 micromol/L to 157 +/- 62 micromol/L (p < 0.05 comparing both groups). Conversion to tacrolimus resulted in a sustained reduction in systolic and diastolic blood pressure, and a sustained improvement in the serum lipid profile, leading to a reduction in the Framingham risk score from 5.7 +/- 4.3 to 4.8 +/- 5.3 (p < 0.05). Finally, conversion to tacrolimus resulted in decreased scores for occurrence of and distress due to side-effects. In conclusion, conversion from cyclosporine to tacrolimus in stable renal transplant patients is beneficial with respect to renal function, cardiovascular risk profile, and side-effects. Therefore, for most renal transplant patients tacrolimus will be the drug of choice when long-term treatment with a calcineurin inhibitor is indicated

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Decreased renal excretion of soluble interleukin-2 receptor α after treatment with daclizumab. Background Daclizumab (±150 kD), a humanized monoclonal antibody (mAb) against the alpha-chain of the membrane-bound interleukin-2 (IL-2) receptor (IL-2R) also binds soluble interleukin-2R α (sIL-2Rα; ±45 kD), and thus may influence the glomerular filtration of sIL-2Rα. Methods We have studied the influence of daclizumab on the renal excretion of sIL-2Rα in 38 recipients of a renal transplant (32 treated with daclizumab and six controls). sIL-2Rα was measured every 2weeks after transplantation in serum and urine with Immulite® IL-2R, a solid-phase enzyme-linked immunosorbent assay (ELISA). Results In the control population, the fractional excretion of sIL-2Rα was relatively constant with a median value of 1.7%± 0.5%. In daclizumab-treated patients, sIL-2Rα was not detectable in the urine immediately after the administration of daclizumab. sIL-2Rα became detectable in the urine at a mean of 8 ± 3weeks after transplantation. In additional experiments, serum compounds were separated by size-exclusion chromatography and sIL-2Rα was measured in the collected fractions. In the control patients, sIL-2Rα was only present in the low-molecular-weight fractions of serum. In contrast, in daclizumab-treated patients evaluated several weeks after transplantation, sIL-2Rα was merely detected in the high-molecular-weight fractions of serum. During follow-up there was a relative shift of sIL-2Rα from the high- to the low-molecular-weight fractions and this coincided with normalization of sIL-2Rα excretion. Conclusion Daclizumab inhibits the renal excretion of sIL-2Rα by the formation of a complex with sIL-2Rα in serum, which is too large for glomerular filtration. Measurement of urinary sIL-2Rα may provide information on the concentration of anti-IL-2Rα mAb in serum.

Item does not contain fulltext Cyclosporine is considered to contribute to the high cardiovascular morbidity and mortality in patients after renal transplantation. Tacrolimus may be more favorable in this respect, but controlled data are scarce. In this prospective randomized study in 124 stable renal transplant patients, the effects of conversion from cyclosporine to tacrolimus on cardiovascular risk factors and renal function were investigated. Follow-up was 6 mo. Statistical analysis was performed by ANOVA for repeated measurements. The serum creatinine level decreased from 137 +/- 30 micromol/L to 131 +/- 29 micromol/L (P < 0.01). Three months after conversion from cyclosporine to tacrolimus, mean BP significantly decreased from 104 +/- 13 to 99 +/- 12 mmHg (P < 0.001). Serum LDL cholesterol decreased from 3.48 +/- 0.80 to 3.11 +/- 0.74 mmol/L (P < 0.001,) and serum apolipoprotein B decreased from 1018 +/- 189 to 935 +/- 174 mg/L (P < 0.001). Serum triglycerides decreased from 2.11 +/- 1.12 to 1.72 +/- 0.94 mmol/L (P < 0.001). In addition, both rate and extent of LDL oxidation were reduced. The fibrinogen level decreased from 3638 +/- 857 to 3417 +/- 751 mg/L (P < 0.05). Plasma homocysteine concentration did not change. Three months after conversion, plasma fasting glucose level temporarily increased from 5.4 +/- 1.3 mmol/L to 5.8 +/- 1.9 mmol/L (P < 0.05). Conversion to tacrolimus resulted in a significant reduction of the Framingham risk score. In conclusion, conversion from cyclosporine to tacrolimus in stable renal transplant patients has a beneficial effect on renal function, BP, serum concentration and atherogenic properties of serum lipids, and fibrinogen.

Item does not contain fulltext Patients who are receiving an organ transplant nowadays are sentenced to the life-long administration of immunosuppressive drugs, which have serious side effects. The reliable induction of donor-specific tolerance therefore remains a major goal in organ transplantation. Previously, we have developed a sublethal, non-myeloablative murine model in which permanent mixed, multilineage chimerism and donor-specific tolerance are established. Our model involves engraftment of fully allogeneic T cell depleted donor bone marrow cells in low dose irradiated and anti-CD3 treated major histocompatibility complex (MHC)-disparate recipient mice. To investigate whether vascularized organ grafts are accepted in our model, we performed heterotopic heart transplantations in our mixed chimeric mice. Chimeric mice permanently accepted hearts from the bone marrow donor (>130 days) and rapidly rejected third party-type allografts (median survival time 9 days). Untreated control recipient mice rejected both donor- and third party-type allografts. In addition, mice that accepted their cardiac grafts, donor-specific acceptance of skin grafts was observed. In conclusion, the establishment of stable mixed chimerism with this low-toxicity regimen resulted in permanent donor-specific acceptance of vascularized organ as well as skin grafts across a full MHC barrier.

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Uncertainty exists regarding the necessity of continuing triple therapy consisting of mycophenolate mofetil (MMF), cyclosporine (CsA), and prednisone (Pred) after kidney transplantation (RTx). At 6 mo after RTx, 212 patients were randomized to stop CsA (n = 63), stop Pred (n = 76), or continue triple drug therapy (n = 73). The MMF dose was 1000 mg twice daily, target CsA trough levels were 150 ng/ml, and Pred dose was 0.10 mg/kg per d. Follow-up was until 24 mo after RTx. Biopsy-proven acute rejection occurred in 14 (22%) of 63 patients after CsA withdrawal compared with 3 (4%) of 76 in the Pred withdrawal group (P = 0.001) and 1 (1.4%) of 73 in the control group (P = 0.0001). Biopsy-proven chronic rejection was present in one patient in the control group, in nine patients after CsA withdrawal (P = 0.006 versus control group); and in four patients after discontinuation of Pred (NS). Graft loss occurred in two versus one patient after CsA or Pred withdrawal, respectively, and in two patients in the control group (NS). Patients who successfully withdrew CsA had a significantly lower serum creatinine during follow-up. Pred withdrawal resulted in a reduction in mean arterial pressure, and the total cholesterol/HDL ratio increased. In conclusion, rapid CsA withdrawal at 6 mo after RTx results in a significantly increased incidence of biopsy-proven acute and chronic rejection. Pred withdrawal was safe and resulted in a reduction in mean arterial pressure. However, patient and graft survival and renal function 2 yr after RTx were not different among groups.

Item does not contain fulltext In a retrospective study we investigated the risk of acute rejection after the withdrawal of mycophenolate mofetil (MMF) in 39 adult patients treated with cyclosporine (CyA), prednisone, and MMF for at least 6 months following renal transplantation. After reaching a stable renal graft function, MMF was withdrawn and CyA and prednisone were continued. Preceding the withdrawal of MMF, four patients experienced an acute rejection. During a median follow-up of 38 months after discontinuing MMF, no acute rejection occurred. The mean serum creatinine level did not change during the first 6 months after withdrawal of MMF. We conclude that elective withdrawal of MMF in stable renal transplant recipients at 6 months after transplantation bears no important risk of an occurrence of acute rejection.

A 40-year-old white woman with end-stage renal disease from idiopathic type I membranoproliferative glomerulonephritis (MPGN) developed proteinuria and renal dysfunction 7 weeks after cadaveric donor renal transplantation. At the same time, a primary cytomegalovirus (CMV) infection was diagnosed. Complement levels were low. A renal biopsy disclosed an acute exudative proliferative glomerulonephritis with influx of polymorphonuclear granulocytes (PMNs), with granular deposits of C3, C1q, IgG, and IgM. The immunofluorescence (IF) and electron microscopy (EM) findings were compatible with an early stage of a type I MPGN. CMV could not be detected in the glomeruli nor elsewhere in the kidney by IF or EM. The patient was treated with ganciclovir. In a renal biopsy 3 weeks later, the exudative lesions had disappeared, and some glomeruli now showed the characteristic lesions of a type I MPGN with an increase of mesangial cells and matrix, and reduplication of the glomerular basement membrane. Over the following period, repeated biopsies were performed. The activity of the glomerular inflammation and immune complex deposits paralleled the waxing and waning of the CMV viral load. After 10.5 months, the graft was removed because of a life-threatening systemic fungal infection. At that time, the CMV infection had cleared, and in the transplantectomy material, the membranoproliferative pattern of injury had disappeared, and in the glomeruli hardly any deposits were found. These data strongly suggest that a primary CMV virus infection can induce an apparent recurrence of type I MPGN.

Background. Mycophenolate mofetil (MMF) is increasingly used for immunosuppression after renal transplantation (RTx). The aim of our study was to investigate if the use of MMF has resulted in an increase in the frequency and severity of primary cytomegalovirus (CMV) infections. Methods. Retrospective study of adult RTx patients who were CMV seronegative and who received a kidney of a CMV seropositive donor in the period 1992 1997 (n=84). Twenty-four of these patients were treated with MMF (in combination with cyclosporin and prednisone; MMF+) and the other 60 were the control group (cyclosporin and prednisone: MMF-). No CMV prophylaxis was given. CMV infection was defined as CMV seroconversion of IgG antibodies. CMV disease was defined as CMV infection and fever in combination with one or more of the following: leukocytopenia, thrombocytopenia, elevated alanine aminotransferase, or histological evidence of tissue invasive disease. Results. The incidence of primary CMV infections was similar in both groups (MMF+, 75%; MMF-, 63%). CMV disease was more frequent in the MMF + group than in the MMF- group (67 vs 30%, P

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Chronic vascular rejection is a major cause of long-term graft failure after renal transplantation. We investigated the effect of the addition of misoprostol (200 μg four times daily) to standard immunosuppressive therapy on the outcome of chronic rejection in a double-blind, placebo-controlled trial. Patients had to fulfill predefined histological and clinical criteria. After an entry of 40 patients into the study (22 misoprostol, 18 placebo), the inclusion of additional patients was terminated because of a high incidence of withdrawal due to adverse effects. Of the patients who used their study medication for at least 3 months (16 misoprostol, 15 placebo), graft function deteriorated in all but 5 misoprostol-treated and all but 2 placebo-treated patients. There was no difference in dialysis-free survival. Withdrawal because of adverse effects (mainly gastrointestinal complaints) occurred in 3 cases in the placebo group and in 11 cases in the misoprostol group (P < 0.05). In conclusion, we found no evidence for a beneficial effect of misoprostol on the course of chronic renal allograft rejection, while use of the drug was accompanied by a high incidence of side effects.

Item does not contain fulltext BACKGROUND: Adherence to immunosuppressive therapy, which is important to prevent rejection after organ transplantation, is influenced by satisfaction of patients with their medication regimen. OBJECTIVE: We investigated the effect of introducing a simplified medication regimen for renal transplant patients on treatment satisfaction, in particular, convenience. METHODS: In a prospective cohort study, treatment was switched from tacrolimus twice daily to tacrolimus once daily with a simultaneous change to a once-daily formulation of other drugs when applicable. Treatment satisfaction was measured in 75 participants with the validated Treatment Satisfaction Questionnaire for Medication version II. RESULTS: The treatment convenience score increased from a mean (SD) of 66.0 (14.5) to 78.5 (14.5) (P < 0.001). The mean (SD) daily number of medication ingestion time points diminished from 2.4 (0.7) to 1.6 (0.7) (P < 0.001), and the mean (SD) daily number of tablets decreased from 12.4 (3.3) to 9.1 (2.6) (P < 0.001). The self-reported adherence to the medication regimen increased from 79.7% to 94.6% (P < 0.001). CONCLUSIONS: The introduction of a simplified medication regimen enabled by the use of a once-daily formulation of tacrolimus increases treatment convenience after renal transplantation. This regimen had a beneficial effect on self-reported adherence.

The etiology of the autoimmune disease systemic lupus erythematosus is not known, but aberrant apoptosis and/or insufficient clearance of apoptotic material have been assigned a pivotal role. During apoptosis, nucleosomes and several endogenous danger-associated molecular patterns are incorporated in blebs. Recent data indicate that apoptotic blebs induce maturation of myeloid dendritic cells, resulting in IL-17 production by T cells. In this review we summarize current knowledge on the role of dendritic cells in the pathogenesis of systemic lupus erythematosus with special emphasis on the uptake of apoptotic blebs by dendritic cells, and the subsequent induction of Th17 cells.

Cyclosporin (CyA) has been demonstrated to increase the vascular resistance of renal allografts (RVR), whereas calcium channel blocking agents like nifedipine may counteract this effect. In this study RVR was calculated from renal blood flow (RBF), measured by the clearance of para-aminohippurate (PAH), and mean arterial pressure (MAP). Analysis of Doppler spectra obtained under ultrasonographic guidance was used as a non-invasive method of assessing renal haemodynamics. A comparison was made between these two methods to detect changes in renal haemodynamics which were caused by the administration of 10 mg nifedipine orally to 11 renal transplant recipients treated with CyA. RBF increased significantly (444 ± 176 vs 559 ± 192 ml/min per 1.73 m2; P

Erythrocytosis after renal transplantation has been ascribed to inappropriate production of erythropoietin by the recipient’s native kidneys. In a retrospective analysis we examined the effect of pre-transplant bilateral nephrectomy on post-transplant haemoglobin level (Hb) and haematocrit (Ht) in 370 renal transplant patients. Hb and Ht were significantly higher in the 341 patients with host kidneys in situ compared with the 29 patients who had undergone bilateral nephrectomy (Hb, 8.5 ± 1.2 mmol/1 vs 7.8 ± 1.3 mmol/1, P = 0.005; Ht, 41 ± 6% vs 38 ± 7%, P = 0.02). Moreover, a very high Hb and/or Ht (defined as a value above the 80th percentile of the whole group) occurred more frequently in patients with host kidneys in situ (20.5% vs 3.5%, P = 0.02). It thus appears that host kidneys significantly contribute to the unexpectedly high haemoglobin levels occurring after renal transplantation.

Purpose The aim of this study was to develop a clinically applicable limited sampling strategy for ambulatory Caucasian kidney transplant patients to estimate area under the curve in a 24-h period (AUC0–24) of prolonged-release tacrolimus. Methods Twenty six kidney recipients, at least 6 months after transplantation, receiving prolonged-release tacrolimus, were enrolled. In each patient, seven blood samples were collected during a period of 24 h by use of the validated dried blood spot method. Best subset selection multiple linear regression was performed to derive limited sampling strategy (LSS). The equations were constrained to include a maximum of three samples collected within 4 h after the intake to maintain clinical applicability. To assess the predictive performance of LSS, residuals for each patient were calculated based on models fitted to a dataset where that patient was omitted. Results The prediction formula for the AUC0–24 using the time points 0, 2, and 4 h after ingestion (C0h-C2h-C4h) provided the highest correlation with the AUC0–24 (r2 = 0.95): AUC0–24 = 44.9 + 8.9 × C0h + 2.1 × C2h + 7.6 × C4h. Measures for bias and precision, i.e., median percentage prediction error (MPPE) and median absolute prediction error (MAPE), were 0.4 and 4.8 %, respectively. For the same patients, the correlation between C24h and AUC0–24 was worse (r2 = 0.77) while MPPE and MAPE were 6.2 and 7.2 %, respectively. Conclusion In the outpatient department, a LSS using C0h-C2h-C4h can be used for reliable estimation of the AUC0–24 of prolonged-release tacrolimus. Electronic supplementary material The online version of this article (doi:10.1007/s00228-015-1863-6) contains supplementary material, which is available to authorized users.

Contains fulltext : 49869.pdf (Publisher’s version ) (Closed access) Blockade of costimulatory signals is a promising therapeutic target to prevent allograft rejection. In this study, we sought to characterize to what extent CTLA-4 engagement contributes to the development of transplantation tolerance under the cover of CD40/CD40L and CD28/CD86 blockade. In vitro, we found that inhibition of the primary alloresponse and induction of alloantigen hyporesponsiveness by costimulation blockade was abrogated by anti-CTLA-4 mAb. In addition, regulatory CD4(+)CD25(+) T cells (T(REG)) were confirmed to play a critical role in the induction of hyporesponsiveness by anti-CD40L and anti-CD86 mAb. Our data indicated that CTLA-4 engagement is not required for activation or suppressor function of T(REG). Instead, in the absence of either CTLA-4 signaling or T(REG), CD8(+) T cell division was enhanced, whereas the inhibition of CD4(+) T cell division by costimulation blockade remained largely unaffected. In vivo, the administration of additional anti-CTLA-4 mAb abrogated anti-CD40L- and anti-CD86 mAb-induced cardiac allograft survival. Correspondingly, rejection was accompanied by enhanced allograft infiltration of CD8(+) cells. We conclude that CTLA-4 signaling and T(REG) independently cooperate in the inhibition of CD8(+) T cell expansion under costimulation blockade.