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Luuk B Hilbrands

Publications and source records attributed to Luuk B Hilbrands.

At least 19 recordsLinked to original sources
PubMed2006

The immunosuppressive drug FK778 induces regulatory activity in stimulated human CD4+ CD25- T cells.

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.

Adult↗
PubMed2006

Ex vivo expansion of human CD4+ CD25high regulatory T cells from transplant recipients permits functional analysis of small blood samples.

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.

CD4-Positive T-Lymphocytes↗
PubMed2006

Dendritic cells activated by lipopolysaccharide after dexamethasone treatment induce donor-specific allograft hyporesponsiveness.

BACKGROUND: Immature dendritic cells (imDC) can prolong allograft survival in murine transplantation models. Recent data indicate that semi-mature or alternatively activated DC (aaDC) may be even more tolerogenic. METHODS: We compared the phenotype and regulatory capacity of: a) imDC, cultured in the presence of dexamethasone (DEX), b) mature DC (matDC), activated with LPS, and c) aaDC, activated with LPS after pretreatment with DEX. RESULTS: As compared to imDC, aaDCs displayed a slight upregulation of CD40 while expression levels of MHC-II and CD86 remained low. The production of proinflammatory cytokines, in particular IL-12, by aaDC was much lower than by matDC while both produced similar amounts of the regulatory cytokine IL-10 leading to an increased IL-10/IL-12 ratio for aaDC. After infusion of donor type aaDCs, responder cells isolated from the recipient mice showed donor-specific hyporesponsiveness to restimulation by matDC. Infusion of matDC was immunogenic, while imDC induced partial hyporesponsiveness. Importantly, pretreatment with donor type aaDC (but not imDC) resulted in prolonged survival of a completely MHC-mismatched heart allograft. CONCLUSIONS: Alternatively activated DC are more efficacious than the classical imDC in the regulation of the alloimmune response, which may be related to a distinct cytokine profile characterized by an increased IL-10/IL12 ratio.

Animals↗
PubMed2006

CTLA-4 engagement and regulatory CD4+CD25+ T cells independently control CD8+-mediated responses under costimulation blockade.

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.

Animals↗
PubMed2006

Alternaria infectoria phaeohyphomycosis in a renal transplant patient.

A male renal transplant patient developed a tumor on the dorsum of his right hand. After excision, histological examination of the tumor showed hyphal structures, but growth developed very slowly. Therapy consisted of surgery alone. A definitive identification of Alternaria infectoria was only possible with molecular techniques.

Alternaria↗
PubMed2005

Rapamycin, and not cyclosporin A, preserves the highly suppressive CD27+ subset of human CD4+CD25+ regulatory T cells.

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.

Cells, Cultured↗
PubMed2005

Tolerizing effects of co-stimulation blockade rest on functional dominance of CD4+CD25+ regulatory T cells.

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.

Animals↗
PubMed2004

Blockade of the renin-angiotensin system increases graft survival in patients with chronic allograft nephropathy.

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.

Adult↗
PubMed2004

No important influence of limited steroid exposure on bone mass during the first year after renal transplantation: a prospective, randomized, multicenter study.

BACKGROUND: 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. METHODS: 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. RESULTS: 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% [P<0.01]; steroids -2.3 +/-4.2% [P<0.01]). In the following months, lumbar BMD recovered in both groups (P<0.01), 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). CONCLUSION: 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.

Acute Disease↗
PubMed2004

The influence of corticosteroids on quantitative ultrasound parameters of the calcaneus in the 1st year after renal transplantation.

Steroid-related bone loss is a recognized complication after renal transplantation. Quantitative ultrasound (QUS) of bone measures bone structure besides bone mass. We investigated the influence of corticosteroid therapy on QUS parameters in the 1st year after renal transplantation. A total of 119 renal transplant recipients were randomized to receive either a steroid-free regimen or a regimen with prednisone during 4 months. In 96 patients (steroid-free n=49, steroids n=47), dual-energy X-ray absorptiometry (DXA) parameters of the lumbar spine and the right hip, and QUS parameters of the right calcaneus were measured at baseline, 3, and 12 months after transplantation. Despite a significant difference in steroid use between the two groups, there was no statistically significant difference between the two groups in DXA and QUS parameters at any time point. BMD of the lumbar spine decreased at 3 months and recovered hereafter to the baseline value. BMD of the femoral trochanter decreased at 3 months and remained stable hereafter. The QUS parameter broadband ultrasound attenuation (BUA) was significantly lower at 12 months after transplantation compared with baseline (steroid-free -4.1+/-1.5%, steroids -2.6+/-1.5%). In contrast to the DXA parameters, BUA continued to decrease (P<0.05) between 3 and 12 months after transplantation in both groups. It is concluded, that the usage of a moderate dose of steroids during 4 months after renal transplantation had no important influence on QUS parameters of the calcaneus. While BMD remained stable or improved between 3 and 12 months after transplantation, the decrease in BUA seems to reflect a continuing change in bone structure in this population with preexistent renal osteodystrophy.

Absorptiometry, Photon↗
PubMed2004

The fractional excretion of soluble interleukin-2 receptor-alpha is an excellent predictor of the interleukin-2 receptor-alpha status after treatment with daclizumab.

BACKGROUND: Daclizumab is a humanized monoclonal antibody against the alpha-chain of the interleukin (IL)-2 receptor (R). The authors previously have shown that the urinary excretion of soluble (s) IL-2Ralpha is dependent on the presence of daclizumab in serum. The authors investigated whether the IL-2Ralpha status, as assessed by flow cytometric analysis, is reflected by the concentration of sIL-2Ralpha in the urine and serum. METHODS: Two hundred seventy-two measurements were performed in 46 renal transplant recipients who were treated with daclizumab in combination with tacrolimus and mycophenolate mofetil. Soluble IL-2Ralpha was measured in urine and serum with Immulite IL-2R, a solid-phase enzyme-linked immunosorbent assay. Complete blockade of the IL-2Ralpha was defined as the presence of less than 5% IL-2Ralpha+ lymphocytes in the CD3+ population. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the performance of serum and urine sIL-2Ralpha in predicting IL-2Ralpha blockade. RESULTS: The calculated fractional excretion of sIL-2Ralpha proved to be an excellent predictor of the blockade of IL-2Ralpha (ROC analysis area under the curve, 0.95+/-0.01). A calculated fractional excretion of sIL-2Ralpha lower than 0.5% had a specificity of 100% and a sensitivity of 75% for the assessment of blockade of IL-2Ralpha. CONCLUSIONS: Blockade of IL-2Ralpha after treatment with daclizumab can reliably be assessed by calculation of the fractional excretion of sIL-2Ralpha. This method is easier to use compared with flow cytometric analysis of IL-2Ralpha+ lymphocytes.

Adult↗
PubMed2004

Steroid-withdrawal at 3 days after renal transplantation with anti-IL-2 receptor alpha therapy: a prospective, randomized, multicenter study.

Steroids 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.

Adolescent↗
PubMed2004

Conversion from cyclosporine to tacrolimus improves quality-of-life indices, renal graft function and cardiovascular risk profile.

Long-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.

Blood Glucose↗
PubMed2003

Decreased renal excretion of soluble interleukin-2 receptor alpha 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 alpha (sIL-2R alpha; +/-45 kD), and thus may influence the glomerular filtration of sIL-2R alpha. METHODS: We have studied the influence of daclizumab on the renal excretion of sIL-2R alpha in 38 recipients of a renal transplant (32 treated with daclizumab and six controls). sIL-2R alpha was measured every 2 weeks 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-2R alpha was relatively constant with a median value of 1.7%+/- 0.5%. In daclizumab-treated patients, sIL-2R alpha was not detectable in the urine immediately after the administration of daclizumab. sIL-2R alpha became detectable in the urine at a mean of 8 +/- 3 weeks after transplantation. In additional experiments, serum compounds were separated by size-exclusion chromatography and sIL-2R alpha was measured in the collected fractions. In the control patients, sIL-2R alpha was only present in the low-molecular-weight fractions of serum. In contrast, in daclizumab-treated patients evaluated several weeks after transplantation, sIL-2R alpha was merely detected in the high-molecular-weight fractions of serum. During follow-up there was a relative shift of sIL-2R alpha from the high- to the low-molecular-weight fractions and this coincided with normalization of sIL-2R alpha excretion. CONCLUSION: Daclizumab inhibits the renal excretion of sIL-2R alpha by the formation of a complex with sIL-2R alpha in serum, which is too large for glomerular filtration. Measurement of urinary sIL-2R alpha may provide information on the concentration of anti-IL-2R alpha mAb in serum.

Adult↗
PubMed2003

Improved cardiovascular risk profile and renal function in renal transplant patients after randomized conversion from cyclosporine to tacrolimus.

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.

Adult↗
PubMed2003

Is serum cystatin C the marker of choice to predict glomerular filtration rate in paediatric patients?

BACKGROUND: It has been suggested that serum cystatin C (cyst-C) concentration provides a better indication of changes in glomerular filtration rate (GFR) than does serum creatinine concentration. METHODS: Because of conflicting results as to the usefulness of cyst-C, we compared the GFRs calculated from serum cyst-C, inulin clearance and endogenous creatinine clearance in children. GFRs calculated from cystatin concentration, inulin clearance following a single injection and endogenous creatinine clearance using Jaffé and enzymic methods were compared in 66 children (1.3-21.9 years) with a variety of renal disorders. Receiver operating curve analysis was used to determine the cut-off value that would give the best discrimination between normal and decreased GFR. RESULTS: The serum cyst-C concentration ranged from 0.66 to 7.61 mg/L (median 1.94). Serum creatinine Jaffé concentration (creat-J) ranged from 38 to 871 micro mol/L (median 105) and creatinine enzymatic concentration (creat-E) ranged from 28 to 862 micro mol/L (median 126). The linear correlation coefficient (R) of 1/cyst-C versus GFR (R = 0.937) did not differ from either that of 1/creat-J versus GFR (R = 0.918) or that of 1/creat-E versus GFR (R = 0.901). These coefficients had overlapping confidence intervals. The areas under the curve for cyst-C, creat-J and creat-E were 0.967, 0.977 and 0.924, respectively, and were not significantly different from each other. For cyst-C, the optimal cut-off was 1.1 mg/L. CONCLUSIONS: Serum cyst-C is equivalent to creat-J and creat-E as a marker for estimating the GFR in the paediatric population studied.

Adolescent↗