Donor-specific HLA antibodies in a cohort comparing everolimus with cyclosporine after kidney transplantation

Donor-specific HLA antibodies (DSA) have a negative impact on kidney graft survival. Therefore, we analyzed the occurrence of DSA and antibody-mediated rejection (AMR) in patients from two prospective randomized trials in our center. At 3-4.5 months posttransplant 127 patients were randomized to continue cyclosporine or converted to everolimus therapy. The presence of DSA was prospectively assessed using Luminex assays. AMR was defined according to the Banff 2009 classification. Antibody screening was available in 126 patients with a median follow-up of 1059 days. Seven out of 65 (10.8%) patients on cyclosporine developed DSA after a median of 991 days. In comparison, 14/61 patients (23.0%) randomized to everolimus developed DSA after 551 days (log-rank: p = 0.048). Eight patients on everolimus compared to two patients on cyclosporine developed AMR (log-rank: p = 0.036). Four of 10 patients with AMR-all in the everolimus group-lost their graft. A multivariate regression model revealed everolimus, >3 mismatches and living donor as significant risk factors for DSA. Acute rejection within the first year, >3 mismatches, everolimus and living donor were independent risk factors for AMR. This single center analysis demonstrates for the first time that everolimus-based immunosuppression is associated with an increased risk for the development of DSA and AMR.

Pharmacokinetics of the immunosuppressant everolimus in maintenance renal transplant patients

The novel macrocyclic immunosuppressant everolimus has been approved for use in renal and heart transplantation. The objective of this randomized, double-blind, placebo-controlled, dose-escalating Phase 1 study was to evaluate the pharmacokinetic profile of different dosing regimens of everolimus. Fifty-four subjects were randomized for 4-weeks treatment with everolimus (n = 44) or placebo (n = 10). Steady state was reached by day 4 of multiple dosing with evidence for dose-proportionality over the dose range tested. Systemic accumulation was 1.6- to 2.2-fold with multiple dosing. Steady-state predose trough concentrations were well correlated with AUC (r = 0.87, p < 0.001). Within-subject coefficients of variation for the tablet formulation ranged from 10-19% and between-subject coefficients from 34-60% for Cmax and AUC. There was no effect of common demographic parameters (age, sex, weight) on variability in steady-state exposure. These results support the clinical use of everolimus in renal transplantation.

Problems of cyclosporine absorption profiling using C2-monitoring

The present study sought to validate the concept of C2 monitoring in 41 de-novo transplant patients treated with microemulsion of cyclosporine, mycophenolatesodium, steroids and basiliximab.

RESULTS

After 6 months patient and graft survival was 98%, rejection rate was 19%. In the first week only a few patients achieved the suggested C2 levels (19% > 1500, 50% > 1200 ng/ml) despite an increased cyclosporine (CsA) dose. After 14 days 63% of patients reached C2 > 1500 ng/ml (83% C2 > 1200) despite decreased CsA dose. 35% of patients had intermittent high C0 (> 300) and low C2 (< 800), suggesting poor and/or slow absorption. Most of them suffered from CsA toxicity. There was a significant (p < 0.05) change of absorption as measured by C2/C0 leading to an increase of C2/dose.

CONCLUSIONS

C2 monitoring may be useful to better estimate the CsA exposure in individual patients; however our results indicate some limitations of the current concept of C2 monitoring. Despite increase of dosage many patients do not reach the proposed levels. A significant proportion of patients are poor and/or slow absorbers. CsA toxicity may not be detected by C2 monitoring alone. With the use of basiliximab and mycophenolatesodium lower target levels seem to be sufficient.

Enteric-coated mycophenolate sodium: safe conversion from mycophenolate mofetil in maintenance renal transplant recipients

Mycophenolate mofetil (MMF), in combination with cyclosporine and corticosteroids, improves long-term graft function and survival in renal transplant recipients. However, optimal MMF therapy may be limited by gastrointestinal (GI) intolerance, which may result in the need for MMF dose reduction, interruption, or discontinuation, leading to increased risk of acute rejection. Enteric-coated mycophenolate sodium (EC-MPS) is an advanced formulation delivering mycophenolic acid (MPA), developed with the objective of improving MPA-related upper GI adverse events. A pivotal, 12-month, phase III, randomized, multicenter, double-blind, double-dummy, parallel group study investigated whether stable renal transplant patients can be converted from MMF to EC-MPS therapy without compromising tolerability or efficacy. Stable renal transplant recipients received either MMF, 1000 mg b.i.d. (n=159), or EC-MPS, 720 mg b.i.d. (n=163), for 12 months. The incidence of GI adverse events was comparable between both treatment groups at 3 and 6 months, but there was a trend toward reduced severity of GI side effects in the EC-MPS group. There were fewer serious adverse events with EC-MPS and significantly fewer serious infections (P<.05). This comparable safety profile for EC-MPS and MMF also extended to elderly patients and patients with diabetes at baseline. For the composite efficacy variable of biopsy-proven acute rejection, graft loss, death, or loss to follow-up, EC-MPS had a lower 12-month efficacy failure rate (EC-MPS: 7.5% vs MMF: 12.3%; P=ns). These data demonstrate that stable renal transplant recipients receiving MMF can be converted to EC-MPS with no efficacy or tolerability compromise.

Cyclosporin C2hour monitoring after renal transplantation

Therapeutic drug monitoring of cyclosporin A (CsA) is essential because of its variable pharmacokinetics in individual patients and its narrow therapeutic window. In the past, standard trough level (C0) monitoring has been used, and although this method is currently the routine strategy, it has been shown that a single blood concentration measurement 2 hours after CsA administration (C2hour) is a significantly more accurate predictor of drug exposure and clinical events than trough concentrations. The CsA absorption profiling, in particular the measurement of C2hour, is a much more sensitive approach to assessing the pharmacokinetics and predicting the clinical effect in the individual patient. However, there are limited prospective data available examining the risks and benefits of C2hour monitoring in renal transplant recipients. Most studies focus on the early post-transplant phase, but there is little experience with C2hour monitoring in maintenance patients. Our experience in 127 stable long-term renal allograft recipients suggests that the therapeutic window for C2hour levels in patients during maintenance is lower than previously anticipated. Repeat determinations of both C0 and C2hour levels in 46 patients to determine precision of C2hour monitoring showed a high intrapatient variability. We observed only a slightly better coefficient of variation for C2hour than for C0 in repeat determinations. This suggests that drug monitoring using C2hour levels in transplant patients may provide a more accurate and reliable measure of drug exposure in the individual patient. However, CsA absorption showed only a weak correlation with dose during repeated measurements, suggesting high variability in absorption in these stable patients. We conclude that an adequate C2hour level soon after transplantation is associated with a reduced risk of acute rejection in adult renal transplant recipients. It is important to identify slow and poor absorbers in the initial phase after transplantation in order to avoid inappropriate increases in CsA dose. In maintenance patients, C2hour values between 500 and 600 ng/ml are effective and safe for providing effective rejection prophylaxis. Although mean C2hour levels do not seem to identify patients at risk of rejection, they may help to identify excessive immunosuppression and to improve long-term survival by reducing CsA toxicity.

Pharmacodynamics of FTY720, the first member of a new class of immune-modulating therapeutics in transplantation medicine

FTY is a novel immunomodulator currently undergoing clinical investigation and has the potential of improving immunosuppressive therapy after organ transplantation. Previous experimental studies in animals have shown that FTY has a unique mechanism of action. We have studied the pharmacodynamic effects of FTY in stable renal allograft recipients taking part in a phase I clinical trial. As in various animal models including non-human primates, a single oral dose of FTY (0.25 - 3.5 mg) significantly reduced peripheral lymphocyte count by 30 - 70%. The peripheral lymphocyte count returned to baseline within 24 hours. Only in those patients treated with the highest dose of FTY (3.5 mg), did peripheral lymphopenia persist for more than 96 hours. FTY reduced all lymphocyte subsets, T cells more than B cells and CD4+ cells more than CD8+ cells. The reduction in CD3+CD62L+ cell counts was more pronounced, whereas CD3+CCR5+ cell counts were less affected in comparison to the total number of CD3+ lymphocytes. We found only slightly increased apoptosis rates (< 5%) in peripheral lymphocytes, and this change does not explain the marked reduction in lymphocyte count. In cultured human lymphocytes only suprapharmacological doses of 10 microM FTY induced apoptosis (20.6 +/- 2.8%) after a 4-h incubation. More important, clinically relevant doses of 0.1 microM FTY increased lymphocyte mobility 2-fold. No effect of FTY on anti-CD3mAb-stimulated lymphocyte proliferation was detected and there was no change in phagocytosis rates in whole-blood cultures incubated with FTY. Further studies are necessary to investigate the mechanism of action of FTY in detail.

Effect of mycophenolate mofetil on IMP dehydrogenase after the first dose and after long-term treatment in renal transplant recipients

OBJECTIVE

Mycophenolate mofetil (MMF) is routinely used as an immunosuppressant in a fixed daily dose regimen although it shows marked fluctuations in pharmacokinetics, and despite the fact that in regard to the active metabolite, mycophenolic acid (MPA), there is a well-known association between the pharmacokinetic parameters and clinical outcome.

METHOD

In order to determine the time course and the variability in cellular target of MPA after renal transplantation, we investigated the pharmacodynamic response in 8 patients receiving 1 g MMF for the first time prior to renal transplantation and in 8 stable renal transplant patients maintained on long-term MMF therapy (1 g b.i.d.) for more than 1 year. The pharmacodynamic response was measured using inosine 5'-monophosphate dehydrogenase (IMPDH) activity in peripheral mononuclear cells. MPA plasma concentrations were measured in parallel, IMPDH activity in 89 healthy blood donors was used as a control.

RESULTS

We observed a high interindividual variability in IMPDH activity in the 89 untreated healthy volunteers (4.0 - 32.9 nmol/h/mg protein), in 8 patients on dialysis (5.3 - 18.9 nmol/h/mg protein) and in 8 renal transplant patients under long-term MMF treatment (2.3 - 14.4 nmol/h/mg protein). The mean AUC0-12h for mycophenolic acid was 2-fold higher in patients receiving long-term treatment with MMF (62.2 +/- 16.6 mg x h/ml) compared to dialysis patients receiving 1 g MMF for the first time (31.5 +/- 15.6 mg x h/ml). Despite this pharmacokinetic difference there were no statistically significant differences in the cellular pharmacodynamic response. Minimal IMPDH activity (1.62 +/- 1.23 vs. 1.77 +/- 1.49 nmol/h/mg protein) and maximal IMPDH inhibition (87.5 +/- 0.08 vs. 77.4 +/- 18.8%) during the dosing interval were similar.

CONCLUSIONS

The considerable interindividual variability in the pharmacokinetics of MMF as well as in the drug target support the use of pharmacodynamic drug monitoring to optimize MMF dosing and to reduce the risk of graft rejection and side effects.

Non-radioactive determination of inosine 5'-monophosphate dehydro-genase (IMPDH) in peripheral mononuclear cells

BACKGROUND

The immunosuppressive activity of mycophenolate mofetil (MMF) is based on the reversible inhibition of inosine 5'-monophosphate dehydrogenase (IMPDH) by mycophenolic acid (MPA). It was the aim of this study to develop a nonradioactive method for specific measurement of IMPDH activity in isolated peripheral mononuclear cells (MNC).

METHODS

The procedure is based on the incubation of lysed MNC with inosine 5'-monophosphate (IMP) followed by direct chromatographic determination of produced xanthosine 5'-monophosphate (XMP). IMPDH activity was measured in MNC of MMF-treated patients and nontreated volunteers.

RESULTS

The within-run (n = 10) and between-run (n = 20) coefficients of variation (CV) for IMPDH activity were < 8% and < 10%, respectively. IMPDH activity in 60 healthy volunteers (19-63 yr) ranged from 4.72 to 32.92 nmol/h/mg protein (mean = 18.39 +/- 6.24). The IC(50) for in vitro inhibition of IMPDH activity was about 2 to 3 microg/L. Application of a single dose of 1 g MMF in dialysis patients resulted in a significant inhibition (by 47-95%; p < 0.05) of IMPDH activity in lysed MNC.

CONCLUSIONS

The proposed assay specifically and reliably measures IMPDH activity in MNC. The procedure is applicable to evaluate pharmacodynamic activity in MMF-treated patients. The observed interindividual variability of IMPDH activity may reflect pharmacodynamic differences in MMF-treated patients.

Prognostic value of the Banff classification

We evaluated whether classification of renal allograft biopsies according to the Banff schema is a predictive parameter for graft survival. All patients who received renal transplants between 1980 and 1994 at the University of Erlangen-Nuremberg (n = 1141) were included. Patients who had undergone a renal biopsy (n = 306) were divided into groups according to the Banff classification. We observed a correlation (P < 0.05) between biopsy findings and the following patient characteristics: donor/recipient age, donor/recipient gender, panel reactive antibodies, maintenance immunosuppression, and primary renal disease. Compared to patients who did not undergo renal biopsy (55.9%), 5-year graft survival was reduced in patients with moderate acute rejection defined by tubulitis (20.6%, P = 0.03) or arteritis (0%; P < 0.0001) and in patients with severe acute rejection (24.4%, P < 0.0001).

CONCLUSIONS

(1). The Banff classification is a predictive parameter for renal allograft survival. (2). Certain characteristics predispose patients to certain biopsy findings.

FTY 720A mediates reduction of lymphocyte counts in human renal allograft recipients by an apoptosis-independent mechanism

The novel immunosuppressive compound FTY 720A posseses a mode of action which is different from all other immunosuppressive drugs. The most prominent feature is a reversible decrease in peripheral lymphocyte counts observed in animal experiments. We investigated in the first human trial (phase 1) whether FTY 720A induces apoptosis of peripheral blood mononuclear cells (PBMC) in stable renal allograft recipients. Monitoring of lymphocyte counts revealed a significant and dose-dependent decrease within 6 h post-FTY 720A dose: placebo 5.1%; 0.25 mg 36.4%; 0.5 mg 40.8%; 0.75 mg 39.4%; 1 mg 45.8%; 2 mg 67.2%; 3.5 mg 64.9%. PBMC apoptosis rates did not change, as determined before intake of FTY 720A and 2 h, 6 h, 24 h and 96 h post-FTY 720A dose. We detected no significant difference in apoptosis rates between patients who received placebo or FTY 720A. However, in vitro experiments showed that high concentrations of FTY 720 A induced apoptosis in human PBMC.

The diagnostic value of GM-CSF and IL-6 determinations in patients after renal transplantation

Cytokines are released by graft-infiltrating cells during cellular rejection. We studied the release of GMCSF and IL-6 and their prognostic significance in predicting rejection. Sequential measurements were made in serum and urine samples with an IL-6 specific cell line and a GMCSF ELISA. Biopsy tissue was snap frozen and examined with immunohistochemical methods. The IL-6 values for normal controls (CTR) and stable transplant patients (PTS) were 5-10 pg/ml in serum and 0-2.5 pg/ml in urine. In 51 biopsy-proven rejections (AR), serum IL-6 values at least doubled in 15 (sensitivity 29%, specificity 87%; 19 +/- 7 vs. 7 +/- 2 pg/ml; P = ns). In urine an increase was observed in 29 of 36 AR (sensitivity 80%, specificity 75%; 92 +/- 34 vs. 5 +/- 1 pg/ml; P < 0.05). After treatment, IL-6 decreased in urine in 26/29 PTS to 7 +/- 2 pg/ml (P < 0.05). In three PTS, rejection persisted, as did their elevated IL-6 urine values. In PTS with urinary tract infections, IL-6 increased in the serum of 13/19 and in the urine of 10/12. GMCSF in serum was not influenced by rejection; however, urine values increased in 22/33 AR (sensitivity 67%, specificity 96%; 22 +/- 5 vs. 4.8 +/- 0.3 pg/ml; P < 0.05). These values decreased (5 +/- 0.3; P < 0.05) after treatment. During infection, increased urinary GMCSF levels were observed in 2/9 PTS. Further analysis revealed a better correlation between elevated cytokine levels and rejection episodes in the early posttransplant period. In kidneys with acute rejection, IL-6 was found in the interstitium of all PTS tested. CTR tissue was negative. In PTS GMCSF was found in arterioles and in infiltrate; however, control tissue also showed some staining. Cytokine labeling in tissue could not be correlated with serum or urine values. We concluded: (1) serum IL-6 and GMCSF are of no value in rejection; (2) in urine, they reflect rejection, especially in the early posttransplant period; however, infection confounds the results; (3) IL-6 staining in tissue may be helpful, but requires more study.

Pharmacodynamic monitoring of mycophenolate mofetil

The immunosuppressive activity of Mycophenolate Mofetil (MMF) is based on the reversible inhibition of inosine-5'-monophosphate dehydrogenase (IMPDH) by mycophenolic acid. Pharmacodynamic monitoring by measurement of IMPDH activity reflects directly the biological response to MMF. For measurement of IMPDH activity in peripheral mononuclear cells we established a modified non-radioactive procedure, based on the incubation of cell lysates with inosine-5'-monophosphate and the chromatographic quantification of produced xanthosine-5'-monophosphate by isocratic ion-pair reversed phase HPLC. The between-run precision and within-run precision were 7% and 5%, respectively. We determined the time course of IMPDH activity in five patients after 1 g MMF and in five healthy subjects without administration of MMF. Additionally, IMPDH activity was determined in a population study of 40 healthy volunteers. In healthy volunteers, we observed a wide range of IMPDH activity (4.7-32.9 nmol/h/mg) with only weak diurnal variation. All patients receiving MMF had a significant reduction of IMPDH activity (65-100%) after administration of the drug. Inhibition persisted for up to 6 hours, and after 11 hours IMPDH activity returned to predose activities. The interindividual variability of IMPDH activity may account for pharmacodynamic differences in MMF-treated patients. Based on pharmacodynamic monitoring better dosing strategies for MMF-treated patients may evolve.

TNF-alpha and IL-1alpha induce apoptosis in subconfluent rat mesangial cells. Evidence for the involvement of hydrogen peroxide and lipid peroxidation as second messengers

Apoptosis of mesangial cells (MC) plays a role in glomerulonephritis (GN). In this study we investigated cytokine-induced apoptosis of cultured rat MC by morphological and biochemical features. TNF-alpha and IL-1alpha induced apoptosis in rat MC in a time- and concentration-dependent fashion. RT-PCR experiments revealed that MC express the TNF-receptor 1 (p60) gene constitutively. TNF-alpha as well as IL-1alpha stimulated the production of reactive oxygen species (ROS) and induced lipid peroxidation. Coincubation with catalase inhibited TNF-alpha and IL-1alpha induced apoptosis as well as lipid peroxidation. TNF-alpha, but not IL-1alpha increased the expression of c-jun. These results provide evidence that TNF-alpha and IL-1alpha induce apoptosis in rat MC with hydrogen peroxide and lipid peroxidation as second messengers. Increased c-jun expression may be a downstream intracellular signal of TNF-alpha-, but not IL-1alpha-induced apoptosis.

Age-matching in renal transplantation

BACKGROUND

So far, the combined influence of donor age and recipient age on renal allograft survival has not been investigated sufficiently. In this retrospective single-centre study we analysed whether the influence of donor age and recipient age on renal allograft survival are dependent on each other.

METHODS

Data from 1269 cadaveric renal allograft transplantations were evaluated. Paediatric donors (<15 years) and paediatric recipients (<15 years) were excluded. Donors and recipients were divided by age: young donors (yd, </=55 years, n=1093), old donors (od, >55 years, n=176), young recipients (yr, </=55 years, n=1058), and old recipients (or, >55 years, n=211). Functional and actual long-term graft survival (8 years) within the four resulting groups was determined: yd/yr (n=926), yd/or (n=167), od/yr (n=132), and od/or (n=44).

RESULTS

Univariate analysis showed that long-term graft survival of both, kidneys from young donors (functional, 66.1 vs 52.2%, P=0.004; actual, 53.3 vs 46.2%, P=0.065) and kidneys from old donors (functional, 68.7 vs 22.5%, P=0.07; actual, 57.1 vs 20.8%, P=0.15) was better in old recipients as compared to young recipients. Multivariate regression analysis revealed that actual graft survival of kidneys from old donors was significantly reduced in young recipients (od/yr) as compared to all other groups (P=0.001; RR, 1. 97; 95% CI, 1.32-2.94). In this group of patients, graft loss was mainly due to acute (33.7%) and chronic (24.0%) rejection.

CONCLUSION

Transplantation of kidneys from 'old' donors into 'young' recipients should be avoided, and these kidneys should be given to age-matched recipients.

Reactivation of tuberculosis after conversion from azathioprine to mycophenolate mofetil 16 years after renal transplantation

The incidence of tuberculosis among transplant recipients is greater than in the general population. Mycophenolate mofetil (MMF) is a potent immunosuppressive agent that has become part of most standard immunosuppressive protocols after renal transplantation. We have recently shown that conversion from azathioprine (AZA) to MMF in patients with chronic allograft dysfunction may be beneficial. Here, we report a patient with a history of pulmonary tuberculosis during his childhood. This patient was converted from AZA to MMF therapy 16 years after allogenic renal transplantation because of chronic allograft dysfunction. Two months later, he developed axillary lymph node tuberculosis caused by Mycobacterium tuberculosis. Because he denied contact with infectious persons, we diagnosed reactivation of old dormant tuberculosis. After surgical extirpation, quadruple antituberculous therapy was administered for 3 months (isoniazid, rifampicin, ethambutol, and pyrazinamide), followed by dual therapy for 3 months (isoniazid and rifampicin), and monotherapy for another 3 months (isoniazid). In the follow-up period, he remained asymptomatic with stable graft function. We conclude that MMF therapy in renal allograft recipients may cause reactivation of old dormant tuberculosis, even in the very late posttransplantation period. In these patients, close monitoring and isoniazid prophylaxis may be useful.

De novo hemolytic uremic syndrome postrenal transplant after cytomegalovirus infection

After renal transplantation, hemolytic uremic syndrome (HUS) may occur as recurrent disease or de novo. Here, we describe the de novo occurrence of HUS immediately after the onset of primary cytomegalovirus (CMV) disease in two renal allograft recipients. Patient no. 1 had primary CMV disease with biopsy-proven CMV esophagitis 2 months after transplantation. Patient no. 2 experienced primary CMV disease with fever and leukopenia 8 years after transplantation. Both patients were treated with intravenous ganciclovir. Both patients developed HUS with biopsy-proven thrombotic microangiopathy in the renal allograft only a few days (3 to 5 days) after the onset of CMV disease. The short interval between the onset of CMV disease and HUS, as well as the parallel course of CMV viremia and HUS in both patients, indicate there may be a pathophysiological link between both diseases. However, because antiviral therapy with ganciclovir was started before the onset of HUS in both patients, we cannot definitely rule out that HUS was triggered by ganciclovir.

De novo hemolytic uremic syndrome postrenal transplant after cytomegalovirus infection

After renal transplantation, hemolytic uremic syndrome (HUS) may occur as recurrent disease or de novo. Here, we describe the de novo occurrence of HUS immediately after the onset of primary cytomegalovirus (CMV) disease in two renal allograft recipients. Patient no. 1 had primary CMV disease with biopsy-proven CMV esophagitis 2 months after transplantation. Patient no. 2 experienced primary CMV disease with fever and leukopenia 8 years after transplantation. Both patients were treated with intravenous ganciclovir. Both patients developed HUS with biopsy-proven thrombotic microangiopathy in the renal allograft only a few days (3 to 5 days) after the onset of CMV disease. The short interval between the onset of CMV disease and HUS, as well as the parallel course of CMV viremia and HUS in both patients, indicate there may be a pathophysiological link between both diseases. However, because antiviral therapy with ganciclovir was started before the onset of HUS in both patients, we cannot definitely rule out that HUS was triggered by ganciclovir.

Treatment of acute c-ANCA-positive vasculitis with mycophenolate mofetil

Acute cytoplasmic antineutrophil cytoplasmic antibody (c-ANCA)-positive vasculitis is usually treated with cyclophosphamide and corticosteroids. The incidence of cyclophosphamide-induced lung injury, a potentially life-threatening event, is about 1%. We report on a patient with a history of cyclophosphamide-induced lung injury 2 months after initial treatment of systemic c-ANCA-positive vasculitis. Six months later, the patient presented with acute renal failure caused by an acute relapse of vasculitis. Mycophenolate mofetil (MMF) is a potent immunosuppressive drug that recently has been shown to be effective in the maintenance therapy of c-ANCA-positive systemic vasculitis. With the patient's informed consent, we started treatment with MMF in combination with corticosteroids. Subsequently, anti-proteinase-3-titer (anti-Pr3-titer) returned to normal and renal function improved. In conclusion, MMF in combination with corticosteroids may be useful in the treatment of acute c-ANCA-positive vasculitis.

The quality of life in end stage renal disease care

The improved prognosis and survival statistics of both renal transplantation and dialysis have focused attention on the quality of life offered by these treatments. Using a standardized questionnaire, we assessed the quality of life of 612 patients undergoing renal replacement therapy at our center. Of these patients, 359 had been transplanted and 253 patients were on dialysis. Concerning the sociodemographic data, only the time on specific treatment was longer in dialysis patients than in transplanted patients (49.2 versus 55.6 months, P < 0.05). Most complaints were more common in dialysis patients than in transplanted patients. Only the side effects of medication were seen more in transplanted patients (P < 0.005). Life satisfaction was higher in transplanted patients than in dialysis patients. Dialysis patients were more anxious (P < 0.05) and more depressed (P < 0.001) than transplanted patients. Transplanted patients also felt that they had more social support than did dialysis patients. Overall life quality was almost equal between patients on hemodialysis and patients on peritoneal dialysis, and between patients on the waiting list for transplantation and those not on the waiting list. Despite a significantly better quality of life after renal transplantation, the percentage of patients working remained unchanged. (57.5% versus 57.8%, P = n.s.). We conclude that despite an improved quality of life after renal transplantation, these patients are economically not more productive than patients on dialysis.

The influence of age on outcome after renal transplantation

The influence of donor age and recipient age on outcome after renal transplantation has been investigated in numerous studies. There is some evidence that patient survival in elderly patients who receive a transplant is significantly higher compared with those, who remain on dialysis. In general, patient survival after renal transplantation is mainly dependent on recipient age and on comorbid conditions. Concerning graft survival, most studies conclude that the survival of kidneys taken from older donors (> 50 years) and very young donors (< 5 years) is reduced. Graft survival was also found to be reduced in very young recipients (< 5 years). Functional graft survival proved to be better in older recipients (> 50 years) as compared to younger recipients, due to a reduced immunologic response capability. Actual graft survival however, where cases of death with functioning graft are included, is fairly equal in both populations. The question, whether the age difference between donor and recipient has an influence on graft survival, needs to be further investigated. In conclusion, donor and recipient age are important risk factors, which may influence outcome after renal transplantation and therefore should be considered carefully.

A dominant mechanism coordinately suppresses the expression of Th2 lymphokines

This study, we present evidence for a negatively acting control mechanism that coordinately suppresses the synthesis of the Th2 lymphokines IL-4, IL-5 and IL-6. This control mechanism operates in the murine thymoma cell line BW 5147. When cells of this line were fused to four independently established, well-defined Th2 cell clones, all resulting 74 lymphokine-secreting hybridomas secreted IL-2 which was not secreted by any of the parental Th2 cell clones. Most interestingly, however, none of the 74 hybridomas retained the capacity of the parental Th2 cells to express IL-4. Likewise, the secretion of IL-5 and IL-6 was also suppressed. Obviously, BW 5147 cells dominated the pattern of lymphokines produced, although the lymphokine pattern of Th2 cells was previously considered to be irreversibly fixed due to terminal differentiation of these cells. Suppression of IL-4 production was also observed at the mRNA level, as tested in Northern blot assays. Putative DNA target sequences for suppression of IL-4 gene transcription were not part of the proximal IL-4 promotor regions. Remote DNA control sequences may exist which coordinately regulate the proper, stage-specific expression of the Th2 lymphokines IL-4, IL-5 and IL-6.

Interleukin-8 expression in patients after renal transplantation

Cellular invasion and cytokine release are important steps in the initiation of rejection. We studied the release of interleukin-8 (IL-8), a potent proinflammatory and chemotactic cytokine, and its prognostic significance in predicting rejection after renal transplantation. Serum and urine samples were analyzed with an IL-8-specific sandwich enzyme-linked immunosorbent assay. Biopsy tissue specimens (n = 20) were snap-frozen and examined with immunohistochemistry using two monoclonal antibodies against human IL-8 (4G9 and 2A8). Serum IL-8 measurements were of no value in predicting rejection due to low sensitivity (24%). In 45 biopsy-proven acute rejections (< 2 months after transplantation), urinary IL-8 concentrations were elevated in 62% (298 +/- 54 pg/mL; P < 0.01), preceding clinical diagnosis of rejection. After treatment, the IL-8 concentration in urine decreased back to normal (33 +/- 4 pg/mL; P < 0.01). The highest urinary IL-8 concentrations were seen in patients with biopsy-proven rejection in combination with acute tubular necrosis (610 +/- 150 pg/mL). This finding was independent of renal function and urinary volume. Only three of 15 rejection episodes in patients more than 2 months after transplantation showed an elevated IL-8 concentration in urine (94 +/- 60 pg/mL). In 10 of 23 patients with infection, a significant increase of IL-8 in urine was observed as well (157 +/- 67 pg/mL; P < 0.05). IL-8-positive staining was found within interstitial mononuclear cells of all biopsy specimens showing rejection. Additionally, the antibody 4G9 stained arteriolar smooth muscle and tubular cells. Interestingly, a few IL-8-positive cells were present in two donor kidneys before transplantation was performed; control tissue was negative. Further investigations are necessary to determine the clinical value of urinary IL-8 determinations in the diagnosis of rejection and to evaluate the role of IL-8 in the pathogenesis of acute allograft rejection.

Interleukin-6 expression after renal transplantation

BACKGROUND

Interleukin-6 (IL-6) is an inflammatory cytokine that plays a role in transplant rejection. We tested the hypothesis that IL-6 levels in serum or urine could be of value in predicting acute and chronic allograft rejection. Furthermore, we examined whether or not such levels reflected IL-6 expression in the kidney.

METHODS

We measured IL-6 and IL-6 soluble receptor (IL-6sR) in serum and urine of 145 transplant patients and 20 normal controls. In parallel, we studied 108 renal biopsies. IL-6 was measured with a bioassay system using an IL-6 dependent cell line. IL-6sR was measured with enzyme-linked immunosorbent assay. The biopsies were examined for IL-6 and IL-6 receptor (IL-6R) expression with immunohistochemistry.

RESULTS

Rejection episodes occurring within 2 months of transplantation were accompanied by elevated IL-6 concentrations in serum (17 +/- 4.8 pg/ml, P < 0.05) and urine (114 +/- 27 pg/ml, P < 0.005), compared to controls. These values returned towards baseline (0-5 pg/ml) after successful rejection treatment. The sensitivity of urine measurements was much higher (93%) than serum (54%). The specificity in serum (70%) and urine (60%) was reduced by infection, acute tubular necrosis, and antithymocyte globulin treatment. Serum and urine IL-6sR values did not correlate with rejection. In biopsy tissue, IL-6 and IL-6R were both elevated during rejection. Especially, mononuclear cells within the interstitial infiltrate stained positive. However, the amount of IL-6 positive cells did not correlate with peripheral IL-6 concentrations.

CONCLUSIONS

Urine but not serum IL-6 values are sensitive indicators of rejection; however, they are confounded by infection, acute tubular necrosis, and certain antirejection treatments. These features limit their usefulness.

Clinical pharmacokinetics of tacrolimus in rescue therapy after renal transplantation

Tacrolimus, a potent new immunosuppressive drug, was introduced for rescue therapy in 25 renal transplant recipients with ongoing rejection (n = 24) or severe cyclosporine toxicity (n = 1). A highly significant (p < 0.001) rise in serum creatinine from 138 +/- 14 (3 months before conversion) to 295 +/- 26 mumol/l preceded conversion to tacrolimus. Tacrolimus rescue therapy started 73 +/- 9 months after transplantation, the follow-up was 8 +/- 1 months. Outcome, pharmacokinetics, and side-effects were analyzed. Patient survival was 100% on tacrolimus therapy. Graft survival was 88% after 3 months, and 70% after 8 months. Serum creatinine remained stable during the observation period (Crea after 8 months: 271 +/- 26 mumol/l). Starting with an initial dose of 9.6 +/- 0.3 mg/day (0.14 +/- 0.01 mg/kg/day) we could reduce tacrolimus dose to 6.0 +/- 0.9 mg/day (0.09 +/- 0.02 mg/kg/day; p < 0.001) after 1 month. Tacrolimus trough levels were adjusted to a therapeutic window of 5-8 ng/ml. We had to perform 3.4 +/- 0.5 dose adjustments per patient mainly within the first month after conversion (70%). A high variability in interindividual tacrolimus dose was noted. Last cyclosporine dose was a good predictor of required tacrolimus dose after 1 month (r = 0.88; p < 0.001). Overall, 82 adverse events were noted, of which 29 (35%) were associated with high trough levels (> 10 ng/ml). In contrast, 3 patients with trough levels < 4 ng/ml had ongoing rejection. Blood pressure and routine laboratory data remained unchanged. Steroid dose could be tapered from 12 +/- 2 to 5 +/- 0.3 mg/day (p < 0.02). Gingival hyperplasia and hirsutism improved after conversion. We conclude: Tacrolimus conversion for rescue therapy after renal transplantation is efficient and safe with target trough levels between 5 -8 ng/ml. Frequent drug monitoring is necessary, especially within the first month after conversion. Previous cyclosporine dose can be used as a guideline for starting dose.

Conversion to microemulsion cyclosporine in stable renal transplant patients: results after one year

We switched 302 renal transplant patients from the conventional to a new microemulsion formulation of cyclosporine, to study the latter's safety and efficacy. We used a simple 1:1 conversion of the patient's total daily dose. We measured trough drug levels as well as serum creatinine, liver enzymes, uric acid, and blood pressure values at baseline and at days 4, 8, 15, 29, and months 3, 6 and 12 after drug substitution. Dose adjustments directed at trough levels 80-120 ng/ml were performed, starting at day 8. Within the 12-month observation period, the cyclosporine dose was reduced by 14.7% (204 +/- 60 mg/day baseline vs 174 +/- 51 mg/day after conversion, p < or = 0.001). By day 8, the 1:1 dosage conversion resulted in a modest mean increase in drug trough levels (114 ng/ml baseline vs 120 ng/ml, p < or = 0.01). This increase was accompanied by an increase in serum creatinine concentration, a decrease in calculated creatinine clearance, and an increase in uric acid values (p < or = 0.05). Liver enzymes remained unchanged while systolic and mean arterial blood pressure decreased (p < or = 0.05). After one month, drug trough levels had decreased to baseline (112 ng/ml) and remained there until month 6. They were significantly lower after 12 months (102 +/- 33 ng/ml, p < or = 0.001). Plasma creatinine values decreased to below baseline by month 6 (p < or = 0.001) and month 12 (p < or = 0.001). Twenty-four (8%) biopsy proven rejection episodes and 7 cases of cyclosporine attributed nephrotoxicity occurred in these 302 patients within these 12 months. We conclude, that a 1:1 conversion from conventional to the microemulsion form of cyclosporine is efficacious and safe. However, we advise an initial 10% decrease in dose reduction in those patients whose trough levels are in the high-normal range.

Substitution of conventional cyclosporin with a new microemulsion formulation in renal transplant patients: results after 1 year

BACKGROUND

A new galenic form of cyclosporin A has been developed, based on microemulsion technology. The bioavailability of the compound is relatively independent of food intake and bile flow. It was the purpose of this prospective clinical trial to study the safety of the microemulsion form of cyclosporin A.

METHODS

Three hundred and two renal transplant patients, stratified according to transplant age, were switched from the conventional to the new microemulsion formulation of cyclosporin A. A 1:1 conversion ration was used. Measurements included CsA levels, S-creatinine, liver enzymes, uric acid, and blood pressure. Measurements were performed at baseline and on days 4, 8, 15, 29 and months 3, 6 and 12 after conversion. Dose adjustments were performed to achieve through levels of 80-120 ng/ml.

RESULTS

Within the 12-month observation period the cyclosporin dose was reduced by 14.7% (from 204 +/- 60 mg/day at baseline to 174 +/- 51 mg/day after conversion, P < 0.001). Acutely, i.e. by day 8, 1:1 dose conversion resulted in a modest increase of mean drug through levels (from 114 ng/ml at baseline to 120 ng/ml, P < 0.01). This increase was accompanied by an increase in serum creatinine concentration, a decrease in calculated creatinine clearance, and an increase in uric acid values (P < or = 0.05). Liver enzymes remained unchanged while systolic and mean arterial blood pressure decrease (P < 0.05). After 1 month, drug through levels had decreased to baseline (112 ng/ml) and remained there until month 6. They were significantly lower after 12 months (102 +/- 33 ng/ml), P <0.001). Creatinine clearance values increased to above baseline at 6 and 12 months. Within the 1-year period there occurred 24 (= 8%) episodes of biopsy proven rejection and seven episodes of cyclosporin-attributed nephrotoxicity.

CONCLUSIONS

The 1:1 conversion from conventional cyclosporin A to the microemulsion formulation s efficacious and safe, but an initial dose reduction of 10% is advised in patients with through levels in the high-normal range.