The significance of pretransplant donor-specific antibodies reactive with intact or denatured human leucocyte antigen in kidney transplantation.

Antibodies recognizing denatured human leucocyte antigen (HLA) can co-react with epitopes on intact HLA or recognize cryptic epitopes which are normally unaccessible to HLA antibodies. Their specificity cannot be distinguished by single antigen beads (SAB) alone, as they carry a mixture of intact and denatured HLA. In this study, we selected pretransplant sera containing donor-specific HLA class I antibodies (DSA) according to regular SAB analysis from 156 kidney transplant recipients. These sera were analysed using a SAB preparation (iBeads) which is largely devoid of denatured HLA class I, and SAB coated with denatured HLA class I antigens. A total of 241 class I DSA were found by regular SAB analysis, of which 152 (63%) were also found by iBeads, whereas 28 (11%) were caused by reactivity with denatured DNA. Patients with DSA defined either by regular SAB or iBeads showed a significantly lower graft survival rate (P = 0·007) compared to those without HLA class I DSA, whereas reactivity to exclusively denatured HLA was not associated with decreased graft survival. In addition, DSA defined by reactivity to class I SAB or class I iBeads occurred more frequently in female patients and in patients with historic HLA sensitization, whereas reactivity to denatured HLA class I was not associated with any of these parameters. Our data suggest that pretransplant donor-specific antibodies against denatured HLA are clinically irrelevant in patients already sensitized against intact HLA.

Pretransplant donor-specific HLA class-I and -II antibodies are associated with an increased risk for kidney graft failure.

Pretransplant risk assessment of graft failure is important for donor selection and choice of immunosuppressive treatment. We examined the relation between kidney graft failure and presence of IgG donor specific HLA antibodies (DSA) or C1q-fixing DSA, detected by single antigen bead array (SAB) in pretransplant sera from 837 transplantations. IgG-DSA were found in 290 (35%) sera, whereas only 30 (4%) sera had C1q-fixing DSA. Patients with both class-I plus -II DSA had a 10 yr graft survival of 30% versus 72% in patients without HLA antibodies (p < 0.001). No significant difference was observed in graft survival between patients with or without C1q-fixing DSA. Direct comparison of both assays showed that high mean fluorescence intensity values on the pan-IgG SAB assay are generally related to C1q-fixation. We conclude that the presence of class-I plus -II IgG DSA as detected by SAB in pretransplant sera of crossmatch negative kidney recipients is indicative for an increased risk for graft failure, whereas the clinical significance of C1q-fixing IgG-DSA could not be assessed due to their low prevalence.

Acute renal failure after allogeneic myeloablative stem cell transplantation: retrospective analysis of incidence, risk factors and survival.

Acute renal failure (ARF) is an important complication after stem cell transplantation (SCT). We retrospectively analysed ARF in 363 recipients of allogeneic myeloablative SCT to identify incidence, risk factors, associated post-transplantation complications and mortality of ARF. ARF was graded as grade 0 (no ARF) to grade 3 (need for dialysis) according to creatinine, estimated glomerular filtration rate and need for dialysis. The incidence of severe renal failure (grades 2 and 3 combined) was 49.6% (180 of 363 patients). Hypertension present at SCT was identified as a risk factor for ARF (P=0.003). Despite this, survival of these patients was not different compared to patients without hypertension. Admission to the intensive care unit (ICU) was a post-transplantation complication significantly associated with ARF (P<0.001). Survival rate was highest in patients with ARF grade 0-1 and lowest in patients with grade 3 (P<0.001). However, after correction for complications associated with high mortality (admission to the ICU, thrombotic thrombocytopenic purpura, sinusoidal occlusion syndrome (SOS) and acute graft-versus-host disease) the significant difference in survival disappeared, showing that ARF without co-morbid conditions has a good prognosis, and ARF with co-morbid conditions has a poor prognosis. This poor prognosis is due to the presence of co-morbid conditions rather than development of ARF itself.

[The importance of HLA-matching before kidney transplantation: a recommendation of the Health Council of the Netherlands]. / Het belang van HLA-matching bij niertransplantatie; een advies van de Gezondheidsraad.

In a recent report, the Health Council of the Netherlands concluded, on the basis of the literature, that HLA-matching is still relevant for graft survival in renal transplant patients. Since the HLA DR antigen system is less heterogeneous than the class I HLA antigen system, it would seem wise to match primarily for these antigens, since this may lead to a reduced exchange of organs between countries and shorten the cold ischaemia period. This may in turn improve the results of transplantation. In the Netherlands, the number of living donor kidney transplants has recently shown a remarkable increase, due partly to the introduction of the paired, living donor, kidney exchange protocol. The introduction of a living donor list exchange programme may further increase this number. Finally, citizens need to be motivated to list themselves as possible organ donors.

Inferior results with basis immunosuppression with sirolimus in kidney transplantation.

BACKGROUND: The introduction of sirolimus has provided the opportunity to develop an immunosuppressive regimen without the nephrotoxic calcineurin inhibitors. METHODS: We conducted a first trial in 30 renal allograft recipients. Ten patients were followed prospectively and received sirolimus, to achieve a target blood level of 10 to 15 ng/ml, induction therapy with one dose of daclizumab, low-dose steroids and mycophenolate mofetil. We compared this group with a historical control group of 20 patients who received our standard treatment consisting of tacrolimus, low-dose steroids, and mycophenolate mofetil. RESULTS: After a mean follow-up of 15 weeks, seven patients developed an acute rejection in the sirolimus group (70%) compared with three patients in the tacrolimus group (15%) (p.<0.01). Because of this unacceptable high rate of acute rejections we conducted a second prospective pilot study in nine patients. These patients received sirolimus in combination with two doses of daclizumab, high-dose steroids and mycophenolate mofetil. No rejections occurred under this immunosuppressive regimen; however, many immunosuppression-related adverse events were seen. CONCLUSION: The present study demonstrates an unacceptably high rate of acute rejections (70%) in patients treated with sirolimus, daclizumab, mycophenolate mofetil and low-dose prednisolone. No rejections but many adverse events were seen when sirolimus was given in combination with high-dose steroids.

Genotyping and preemptive isolation to control an outbreak of vancomycin-resistant Enterococcus faecium.

BACKGROUND: Control of vancomycin-resistant Enterococcus faecium (VRE) in European hospitals is hampered because of widespread asymptomatic carriage of VRE by healthy Europeans. In 2000, our hospital (The University Medical Center Utrecht, Utrecht, The Netherlands) was confronted with a large outbreak of VRE. INTERVENTION: On the basis of genotyping (by pulsed-field gel electrophoresis), epidemic and nonepidemic VRE strains were distinguished, and infection-control measures were exclusively targeted toward epidemic VRE. The outbreak was retrospectively divided into 3 periods of different infection-control measures. Compliance with use of alcohol-based hand rubs was enforced during all periods. Period I involved active surveillance, isolation of carriers, and cohorting (duration, 4 months); preemptive isolation of high-risk patients for VRE colonization was added in period II (7 months); and cohorting and preemptive isolation were abandoned in period III (18 months). METHODS: When the outbreak was identified, 27 patients in 6 wards were colonized; 93% were colonized with an epidemic VRE strain. Detection rates of nonepidemic VRE were 3.5%, 3.0%, and 2.9% among 683, 810, and 977 screened patients in periods I, II, and III, respectively, comparable to a prevalence of 2% (95% confidence interval [CI], 1%-3.5%) among 600 nonhospitalized persons. The relative risks of detecting epidemic VRE in periods II and III, compared with period I, were 0.67 (95% CI, 0.41-1.10) for period II and 0.02 (95% CI, 0.002-0.6) for period III. Infection-control measures were withheld for patients colonized with nonepidemic VRE (76 [54%] of 140 patients with a test result positive for VRE). Use of alcohol-based hand rubs increased by 31%-275% in outbreak wards. CONCLUSION: Genotyping-targeted infection control, isolation of VRE carriers, enhancement of hand-hygiene compliance, and preemptive isolation successfully controlled nosocomial spread of epidemic VRE infection.

[Activity loss of Von Willebrand factor cleaving protein (ADAMTS-13) is diagnostic for primary and pregnancy-related thrombotic thrombocytopenic purpura]. / Afwezige activiteit van Von Willebrand-factorsplitsend eiwit (ADAMTS-13) diagnostisch voor primaire en zwangerschapsgerelateerde trombotische trombocytopenische purpura.

OBJECTIVE: To determine whether the measurement of the Von Willebrand factor cleaving protease ADAMTS-13, such as is carried out at the University Medical Centre of Utrecht, The Netherlands, contributes towards the diagnosis and treatment of patients with thrombotic thrombocytopenic purpura (TTP). DESIGN: Descriptive. METHOD: In a group of 98 patients from 21 hospitals, with a Coombs-negative haemolytic anaemia and thrombocytopenia, the ADAMTS-13 activity was measured. Treatment was given irrespective of ADAMTS-13 activity. RESULTS: ADAMTS-13 activity was absent in 27 of 29 patients diagnosed with primary TTP and in all 5 pregnancy-TTP patients. In patients suffering from TTP after bone marrow transplantation (post-BMT) and in all other patients included in this study, ADAMTS-13 activity was normal. Of the 32 patients with absent ADAMTS-13 activity, 28 underwent plasmapheresis. This treatment proved effective as all 28 patients responded well. 17 patients with normal ADAMTS-13 activity also underwent plasmapheresis; 5 (30%) responded well to treatment. In 2 cases a final diagnosis of primary TTP was made, in a further 2, haemolytic uraemic syndrome and in 1 case sepsis was diagnosed. CONCLUSION: In this study, the absence of ADAMTS-13 activity predicted primary TTP and TTP of pregnancy with a sensitivity of 93% and a specificity of 100%. Absence of ADAMTS-13 activity is a strong indication for plasma exchange.

['New pathways to organ donation'; a recommendation of the Dutch Health Council]. / 'Nieuwe wegen naar orgaandonatie'; een advies van de Gezondheidsraad.

Despite recent efforts at improvement, the current status of postmortem organ donation in the Netherlands is a reason for serious concern. The waiting lists for all organ transplantations are increasing in length. The Dutch Health Council was asked by the Minister of Health to report on any available alternative sources of donor organs, focusing especially on donation from living donors and postmortem donors in whom the heart is no longer beating. Kidney donation by living relatives is a well-known procedure that has been performed since 1950. Since HLA-matching is now less important due to new immunosuppressive regimens, transplants from unrelated living volunteers are also possible with good results. Live donation from emotionally involved persons should be encouraged. In case of ABO incompatibility, donors could be exchanged via the organ exchange institution. Live donation of liver segments by an adult to benefit a child recipient is justified. In case of an adult recipient this should be performed only under exceptional circumstances. Live donation of lung lobes and segments of intestine is still in a developmental phase. Postmortem donation of kidneys and livers from donors in whom the heart is no longer beating should also be encouraged. Donation of the lungs and pancreas from these donors is still an experimental procedure.

Quantitative baseline renography 48 hours after renal transplantation predicts long-term graft survival.

Technetium-99m mercaptoacetylglycine (99mTc-MAG3) renography is a successful non-invasive method for the evaluation of renal transplants. In this study we prospectively studied 256 patients after renal transplantation, using the MAG3 uptake capacity in the first 10 min (MUC10), which is an index of renal function representing kidney activity as a fraction of the injected dose. Renal scintigraphy was performed in all patients within 48 h of transplantation. Renograms were obtained over 20 min, after bolus injection of +/-100 MBq 99mTc-MAG3. MUC10 ranged between 0.0 and 94.9. The patients were divided into five groups: group 1, MUC10 <1; group 2, 1< or =MUC10 < 5; group 3, 5 < or = MUC10 <10; group 4, 10 < or = MUC10 < 30; group 5, MUC10 > or =30. In 235 patients, follow-up for 5 years was completed. Considering all the renal transplants, 30% of the grafts ceased functioning within the first 5 years. Six grafts showed a MUC10 of < 1, and none survived the first year. After 5 years, 43% of the grafts with a MUC10 of 1-5 still functioned, as compared with 63% of those with a MUC10 of 5-10, 72% of those with a MUC10 of 10-30 and 83% of those with a MUC10 of > or =30. Kaplan-Meier survival analysis showed significant differences between the five different patient groups based on MUC10 in terms of the percentage of kidneys that ceased to function within 5 years. The period of cold ischaemia and the donor age were known in 178 patients. In contrast to cold ischaemia time, the MUC10 and the donor age showed a significant effect (P<0.05) on graft survival. This study indicates that the MUC10 early after renal transplantation is useful as a prognostic factor in the evaluation of kidney transplants and that a MUC10 of <1 indicates a dismal prognosis for the renal transplant.

Cyclosporine is associated with endothelial dysfunction but not with platelet activation in renal transplantation.

BACKGROUND: Cyclosporine (CsA) is associated with thrombotic micro-angiopathy and endothelial dysfunction. Markers of endothelial dysfunction may serve to identify patients at risk for development of vascular injury. In this study we measured von Willebrand Factor (vWF) and sP-selectin as possible markers for endothelial dysfunction in renal transplant recipients at different concentrations of CsA. Because sP-selectin can also be derived from platelets an additional in vitro study was performed to study the potential effect of CsA on the expression of P-selectin on platelet surface, while the effects of CsA on the interaction of platelets with Endothelial Cell Matrix (ECM) were studied under flow conditions in a perfusion chamber model. METHODS: CsA was stepwisely replaced by mycophenolate mofetil (MMF) in 15 renal transplant recipients (more than 6 months after transplantation). VWF and sP-selectin were measured at normal CsA (median trough level 130 microg/l), low CsA (trough level 45 microg/l) and after stopping CsA. MMF 2 g daily was added while lowering and stopping CsA. Platelet activation was investigated by measurement of P-selectin on platelet surface by flow-cytometry (FACS), after incubation with CsA (0, 2, 20 and 200 mg/l) in vitro and after perfusion of whole blood over ECM with CsA (0 or 2 mg/l, peak levels). RESULTS: Stepwise withdrawal of CsA gave a dose-related decrease of both vWF and sP-selectin, suggesting reversible endothelial dysfunction. FACS showed no expression of P-selectin on platelets by CsA. Also perfusion studies over ECM demonstrated no platelet activation by CsA but even inhibition of platelet adhesion and aggregation. CONCLUSIONS: The use of CsA is not accompanied by platelet activation. However endothelial dysfunction induced by CsA does occur as reflected by increased vWF and sP-selectin. (See Editorial p. 1).

Conversion to mycophenolate mofetil in conjunction with stepwise withdrawal of cyclosporine in stable renal transplant recipients.

BACKGROUND: Mycophenolate mofetil (MMF) is now part of standard immunosuppression in the first phase after renal transplantation. A relevant question is if it can replace drugs such as cyclosporine (CsA) in the maintenance treatment, improving cardiovascular risk profile. METHODS: In 17 patients with a stable renal function (at least 6 months) posttransplantation, we studied the effect of CsA replacement by MMF. After starting MMF (1 g b.i.d.), CsA dosage was reduced from regular to low (median trough level 130 microg/L, respectively, 45 microg/L), followed by complete withdrawal, while prednisone (7.5 mg daily) was continued. We measured ambulatory blood pressure, glomerular filtration rate, renal plasma flow, renal vascular resistance, and metabolic factors at start and after 8 weeks on regular, low-dose CsA, respectively, no CsA with MMF and prednisone. RESULTS: Two patients dropped out after the switch to low-dose CsA/MMF, due to diarrhea in one and a steroid responsive rejection in the other. The complete switch from CsA to MMF was successful in all 15 patients and accompanied by a decrease in 24 hr systolic blood pressure (from 152+/-13 to 145+/-13 mmHg; P<0.01), diastolic blood pressure (93+/-9 to 89+/-12 mmHg; P<0.05), RVR (0.29+/-0.06 to 0.25+/-0.09 mmHg.ml/min; P<0.05), and an increase in glomerular filtration rate (46.6+/-8.8 to 58.0+/-10.5 ml/min; P<0.01) and renal plasma flow. Intermediate low density lipoprotein-cholesterol decreased (0.79+/-0.37 to 0.41+/-0.16 mmol/L; P<0.01). High density lipoprotein-cholesterol decreased, but remained in the safe range. After 1 year two patients stopped the MMF; one because of Kaposi's sarcoma and one because of recurrent infections CONCLUSIONS: The stepwise switch from CsA to MMF was safe and mostly successful, and had beneficial effects on blood pressure, glomerular hemodynamics, and lipid profile. Beneficial trends were already present after partial withdrawal of CsA.

[Daclizumab and basiliximab: monoclonal mouse-man antibodies with effective immunosuppression without side effects]. / Daclizumab en basiliximab: monoklonale muis-mensantistoffen met effectieve immuunsuppressie zonder bijwerkingen.

Four major double-blind randomized trials in kidney transplant patients have shown that the interleukin-2 receptor (IL-2R alpha) antagonists declizumab or basiliximab, when added to an immunosuppressive regimen consisting of cyclosporin and prednisone, reduce the incidence of acute rejections after kidney transplantation by 30-40%, during the first 6 months. Daclizumab and basiliximab are monoclonal antibodies of which the variable parts are of mouse origin and the other components of human origin. The addition of the interleukin-2 receptor antagonists was not accompanied by extra side effects. Ongoing clinical trials aim at answering the question whether the addition of daclizumab and basiliximab will allow to avoid or decrease the use of more toxic immunosuppressive drugs.

[Epidemiologic increase of various genotypes of vancomycin-resistant Enterococcus faecium in a university hospital]. / Epidemische verheffing van verscheidene genotypen van vancomycineresistente Enterococcus faecium in een academisch ziekenhuis.

After a report of a possible relationship between an outbreak of vancomycin-resistant enterococci (VRE) in a nearby hospital and earlier admission of two of the patients with this VRE in the University Medical Centre of Utrecht (UMCU), the Netherlands, an extensive search for VRE carriers was started in the UMCU. In the study period of two months, VRE carriership was diagnosed in 51 patients in nine of the 11 wards investigated. Twenty-six patients in eight wards were colonized with the same VRE genotype as in the nearby hospital; spread was demonstrated in three wards. In addition, six patients of one ward were colonized with a second genotype and seven other patients with a third genotype, while 12 patients were carriers of a unique genotype. Most carriers were found in the internal medicine/nephrology and dialysis ward. Far-reaching measures (such as cohort nursing, admission stops, use of gowns and gloves, disinfection and restriction of use of vancomycin) taken in the four wards where spread was demonstrated, appeared effective but in three wards, spread was again demonstrated later. Frequent readmissions and transfers of patients appear to play an important part in this matter. None of the 51 colonized patients developed a serious VRE infection.

Effect of cyclosporine on mycophenolic acid trough levels in kidney transplant recipients.

BACKGROUND: Triple drug treatment consisting of mycophenolate mofetil (MMF), in a standard dose of 2 g daily, combined with cyclosporine (CsA) and prednisone, has become the standard immunosuppressive regimen after kidney transplantation in many centers. The need for therapeutic drug monitoring of mycophenolic acid (MPA) has not yet been established. Several drug interactions with MMF are known. We investigated the influence of CsA withdrawal on MPA trough levels in renal transplant patients. METHODS: Fifty-two patients were treated with 1 g of MMF twice daily, and prednisone and CsA targeted between 125 and 175 ng/ml for 6 months after transplantation. At 6 months after transplantation, 19 patients were randomized for continuation of triple therapy (group A), 19 patients discontinued CsA (group B), and 14 patients discontinued prednisone (group C). We compared 12-hr fasted MPA trough levels at 6 and 9 months after transplantation within and between these groups. RESULTS: MPA trough levels during treatment with CsA, MMF, and prednisone were significantly lower than those during treatment with MMF and prednisone only (group B); median levels were 1.87 mg/L (range: 0.56-5.27) vs. 3.16 mg/L (range: 0.32-7.78), respectively (P=0.002). MPA trough levels in groups A and C did not change between 6 and 9 months after transplantation; group A median levels were 1.87 (range: 0.31-4.32) vs. 1.53 mg/L (range: 0.36-3.70), and group C median levels were 1.62 (range: 0.69-10.34) vs. 1.79 mg/L (range: 0.54-6.00), respectively. At 9 months after transplantation, patients in whom CsA was discontinued had higher MPA trough levels as compared with patients who continued the use of triple therapy (P=0.001) or patients in whom steroids were withdrawn (P=0.014). CONCLUSION: A significant increase of MPA trough levels was found after discontinuation of CsA (6 months after transplantation), resulting in almost a doubling of MPA trough levels at 9 months after transplantation. This resulted in increased MPA levels in patients without CsA as compared to MPA levels in patients continuing triple therapy or discontinuing prednisone.

A randomized double-blind, multicenter plasma concentration controlled study of the safety and efficacy of oral mycophenolate mofetil for the prevention of acute rejection after kidney transplantation.

BACKGROUND: Adding a fixed dose of 1 g b.i.d. of mycophenolate mofetil (MMF) to an immunosuppressive regimen consisting of cyclosporine and prednisone results in a 50% reduction in the incidence of acute rejection after kidney transplantation. This study was designed to investigate the relationship between pharmacokinetic data (mycophenolic acid area under the curve; MPA AUC) and the prevention of rejection after kidney transplantation. METHODS: A total of 154 adult recipients of a primary or secondary cadaveric kidney graft were randomly allocated, in this double-blind trial, to receive MMF treatment aimed at three predefined target MPA AUC values (16.1, 32.2, and 60.6 microg x hr/ml). During the first 6 months after transplantation, plasma samples for nine AUCs were collected. After analysis of the samples, a coded dose adjustment advice was generated using a Bayesian algorithm, maintaining the double blinding. Immunosuppressive therapy further consisted of cyclosporine and prednisone. The primary end point of this study was the occurrence of biopsy-proven acute rejection within the 6-month study period. RESULTS: A total of 150 patients were eligible for analysis. Although after day 21, the mean MMF dose was reduced, the mean MPA AUC gradually increased and target MPA AUC values were exceeded in all three groups. The incidences of biopsy-proven acute rejection in the low, intermediate, and high target MPA AUC groups were 14 of 51 (27.5%), 7 of 47 (14.9%), and 6 of 52 (11.5%), respectively. The incidences of premature withdrawal from the study due to adverse events in the three groups were 4 of 51 (7.8%), 11 of 47 (23.4%), and 23 of 52 (44.2%), respectively. Logistic regression analysis showed a highly statistically significant relationship between median ln(MPA AUC) and the occurrence of a biopsy-proven rejection (P<0.001). The logistic regression using median ln(Cpredose) was also statistically significant for this relationship (P=0.01), whereas it was not when using mean MMF dose (P=0.082). In contrast, the logistic regression using mean MMF dose for comparison of patients who successfully completed the study versus patients experiencing premature withdrawal due to adverse events was highly significant (P<0.001), whereas this was not significant when using median ln(Cpredose) (P=0.512) or median ln(MPA AUC) (P=0.434). CONCLUSION: MPA Cpredose and MPA AUC are significantly related to the incidence of biopsy-proven rejection after kidney transplantation, whereas MMF dose is significantly related to the occurrence of adverse events.