Ischemia times and donor serum creatinine in relation to renal graft failure.

BACKGROUND: The results of renal transplantation are dependent on many variables. To simplify the decision process related to a kidney offer, the authors wondered which variables had the most important influence on the graft failure risk. METHODS: All transplant patients (n=1,124) between January 1981 and July 2000 were included in the analysis (2.6% had missing values). The variables included were donor and recipient age and gender, recipient original disease, race, donor origin, current smoking, cardiovascular disease, body weight, peak and current panel reactive antibody (PRA), number of preceding transplants, type and duration of renal replacement therapy, and time since failure of native kidneys. Also, human leukocyte antigen (HLA) identity or not, first and second warm and cold ischemia times, left or right kidney and fossa, donor kidney anatomy, donor serum creatinine and proteinuria, and transplantation year were included. RESULTS: In a multivariate model, cold ischemia time and its time-dependent variable significantly influenced the graft failure risk censored for death (P<0.0001) independent of any of the other risk factors. The influence primarily affected the risk in the first week after transplantation; thereafter, it gradually disappeared during the first year after transplantation. Donor serum creatinine also significantly influenced the graft failure risk in a time-dependent manner (P<0.0001). The risk of a high donor serum creatinine is already enlarged in the immediate postoperative phase and increases thereafter; the curve is closely related to the degree of the elevation. The other variables with a significant influence on the graft failure rate were, in order of decreasing significance, recipient age, donor gender, donor age, HLA identity, transplantation year, preceding transplantations, donor origin, and peak PRA. CONCLUSIONS: Donor serum creatinine and cold ischemia time are important time-dependent variables independently influencing the risk of graft failure censored for death. The best strategy for improving the results of cadaveric transplantations is to decrease the cold ischemia time and to allocate kidneys from donors with an elevated serum creatinine to low-risk recipients.

The Cox proportional hazards analysis in words: examples in the renal transplantation field.

When renal transplantation was still in its infancy, failures were more prevalent and successes could be directly derived from facts and events. Because results have improved dramatically over the last decades and many factors have seemed to be involved in these continuously improving results, it is difficult to ascertain the individual contribution of each factor. Survival analysis is the appropriate method for evaluation of factors influencing results of renal transplantation. In this overview, two different methods for survival analysis are compared and described. The Kaplan-Meier analysis is the oldest and most frequently used in renal transplantation epidemiology. Important shortcomings of this method are described and substantiated with examples. The Cox proportional hazards (PH) analysis was developed in 1972 by Sir David Cox. With this multivariable analysis it is possible to identify those variables that influence the rate of failure. With this method, the influences of all other variables in the model are taken into consideration, and adjustment for interaction with other variables or with time can be made. In this article, the Cox analysis and the statistical terms that go with it are described in words and examples are given. In a complex, observational study concerning a multifactor-influenced population such as the renal transplant population, the use of the Cox model is mandatory to unravel the influences of the different variables on the failure rate.

Cholesterol as an independent predictor of outcome after renal transplantation.

BACKGROUND: The debate on the role of high serum cholesterol levels in cardiovascular disease or chronic vascular rejection in kidney-transplanted patients has not yet been settled. METHODS: We studied the influence of serum cholesterol at 1 year after transplantation on the failure risk in all 676 kidney graft recipients who survived with a functioning graft. Other variables included in this analysis were donor/recipient age and gender, original disease, race, number of HLA-A and -B mismatches, previous transplants, postmortal or living-related transplantation, and transplantation year. At 1 year after transplantation, we included: serum cholesterol, serum creatinine, proteinuria, and hypertension. RESULTS: In the Cox proportional hazards analysis, serum cholesterol at 1 year after transplantation turned out to be an important, independent variable influencing all end points (adjusted for all other variables in the model). The influence on graft failure censored for death was log-linear, and there was interaction with serum creatinine at 1 year. The adverse effect of elevated serum cholesterol levels on the graft failure rate decreased with increasing serum creatinine levels. The influence of serum cholesterol on the rate ratio (RR) for patient failure was linear too, and here there was interaction with recipient age. The negative influence of serum cholesterol on the RR for patient failure decreased with increasing recipient age. The risk for over-all graft failure was influenced by increasing serum cholesterol levels, and there was interaction with recipient age. Because recipient age had interaction with donor age and serum creatinine, the influence of all four variables together on the RR was estimated. It is shown that whereas the RR for over-all graft failure in young recipients of a renal transplant increases significantly with higher cholesterol levels, there is very little influence on the RR of elderly recipients. The risk increases proportionally with increasing serum creatinine levels. CONCLUSION: Serum cholesterol levels have an independent influence on graft, patient, and over-all graft failure.

Proteinuria after renal transplantation affects not only graft survival but also patient survival.

BACKGROUND: Proteinuria is associated with an increased risk of renal failure. Moreover, proteinuria is associated with an increased death risk in patients with diabetes mellitus or hypertension and even in the general population. METHODS: One year after renal transplantation, we studied the influence of the presence of proteinuria on the risk of either graft failure or death in all 722 recipients of a kidney graft in our center who survived at least 1 year with a functioning graft. Proteinuria was analyzed both as a categorical variable (presence versus absence) and as a continuous variable (quantification of 24 hr urine). Other variables included in this analysis were: donor/recipient age and gender, original disease, race, number of HLA-A and HLA-B mismatches, previous transplants, postmortal or living related transplantation, and transplantation year. At 1 year after transplantation, we included: proteinuria, serum cholesterol, serum creatinine, blood pressure, and the use of antihypertensive medication. RESULTS: In the Cox proportional hazards analysis, proteinuria at 1 year after transplantation (both as a categorical and continuous variable) was an important and independent variable influencing all endpoints. The influence of proteinuria as a categorical variable on graft failure censored for death showed no interaction with any of the other variables. There was an adverse effect of the presence of proteinuria on the graft failure rate (RR=2.03). The influence of proteinuria as a continuous variable showed interaction with original disease. The presence of glomerulonephritis, hypertension, and systemic diseases as the original disease significantly increased the risk of graft failure with an increasing amount of proteinuria at 1 year. The influence of proteinuria as a categorical variable on the rate ratio for patient failure was significant, and there was no interaction with any of the other significant variables (RR=1.98). The death risk was almost twice as high for patients with proteinuria at 1 year compared with patients without proteinuria. The influence of proteinuria as a continuous variable was also significant and also without interaction with other variables. The death risk increased with increasing amounts of proteinuria at 1 year. Both the risks for cardiovascular and for noncardiovascular death were increased. CONCLUSION: Proteinuria after renal transplantation increases both the risk for graft failure and the risk for death.

Addition of isradipine (Lomir) results in a better renal function after kidney transplantation: a double-blind, randomized, placebo-controlled, multi-center study.

BACKGROUND: After successful kidney transplantation patients may suffer from the adverse effects due to the use of calcineurin inhibitors. Calcium channel blockers are effective in the treatment of hypertension and may ameliorate cyclosporine- (CsA) induced impairment of renal function after kidney transplantation. Calcium channel blockers may also modulate the immune-system which may result in reduction of acute rejection episodes. PATIENTS AND METHODS: From June 1995 till 1997 the effect of isradipine (Lomir) on renal function, incidence and severity of delayed graft function (DGF), and acute rejection after kidney transplantation, was studied in 210 renal transplant recipients, who were randomized to receive isradipine (n=98) or placebo (n=112) after renal transplantation in a double-blind fashion. RESULTS: In the isradipine group renal function was significantly better at 3 and 12 months (P=0.002 and P=0.021) compared with the placebo group. DGF was present in both groups: isradipine: (28+6)/98 (35%); placebo: (35+9)/112 (40%), P=0.57. Severity of DGF was comparable in both groups (isradipine: 9.1+/-8.7 vs. placebo: 9.3+/-8.1 days). No statistical difference was found in incidence or severity of biopsy-proven acute rejection [isradipine: (42+6)/98 (49%) versus placebo: (46+9)/112 (49%), P=1.00]. Renal vein thrombosis was observed in eight patients. This proved to be associated with the route of administration of the study medication [6/45 (13%) on i.v. medication versus 2/165 (1%) on oral medication, P<0.001]. CONCLUSIONS: Addition of isradipine results in a better renal function after kidney transplantation, without effect on incidence or severity of DGF or acute rejection.

The superior results of living-donor renal transplantation are not completely caused by selection or short cold ischemia time: a single-center, multivariate analysis.

BACKGROUND: The results of living-donor (LD) renal transplantations are better than those of postmortem-donor (PMD) transplantations. To investigate whether this can be explained by a more favorable patient selection procedure in the LD population, we performed a Cox proportional hazards analysis including variables with a known influence on graft survival. METHODS: All patients who underwent transplantations between January 1981 and July 2000 were included in the analysis (n=1,124, 2.6% missing values). There were 243 LD transplantations (including 30 unrelated) and 881 PMD transplantations. The other variables included were the following: donor and recipient age and gender, recipient original disease, race, current smoking habit, cardiovascular disease, body weight, peak and current panel reactive antibody, number of preceding transplants and type and duration of renal replacement therapy, and time since failure of native kidneys. In addition, the number of human leukocyte antigen identical combinations, first and second warm and cold ischemia periods, left or right kidney and fossa, donor kidney anatomy, donor serum creatinine and proteinuria, and transplantation year were included. RESULTS: In a multivariate model, donor origin (PMD vs. LD) significantly influenced the graft failure risk censored for death independently of any of the other risk factors (P=0.0303, relative risk=1.75). There was no time interaction. When the variable cold ischemia time was excluded in the same model, the significance of the influence of donor origin on the graft failure risk increased considerably, whereas the magnitude of the influence was comparable (P=0.0004, relative risk=1.92). The influence of all other variables on the graft failure risk was unaffected when the cold ischemia period was excluded. The exclusion of none of the other variables resulted in a comparable effect. Donor origin did not influence the death risk. CONCLUSION: The superior results of LD versus PMD transplantations can be partly explained by the dichotomy in the cold ischemia period in these populations (selection). However, after adjustment for cold ischemia periods, the influence of donor origin still remained significant, independent of any of the variables introduced. This superiority is possibly caused by factors inherent to the transplanted organ itself, for example, the absence of brain death and cardiovascular instability of the donor before nephrectomy.

Anti-CD25 monoclonal antibody therapy affects the death signals of graft-infiltrating cells after clinical heart transplantation.

BACKGROUND: To define whether immunosuppressive agents that block the interleukin (IL)-2 pathway could prevent activation-induced cell death of activated T cells in the graft, we measured expression of IL-2, IL-2 receptor alpha chain (CD25), IL-15, Fas, and Fas ligand by real time reverse transcription-polymerase chain reaction in cardiac allografts. METHODS: We characterized the phenotype of the infiltrating cells (CD3, CD68, CD25) by immunohistochemistry. The proportion of apoptotic graft-infiltrating cells was determined by TUNEL (terminal deoxynucleotidyl transferase dUTP nick-end labeling) staining. We analyzed endomyocardial biopsy specimens from cardiac allograft recipients who were treated with anti-CD25 monoclonal antibody (mAb) induction therapy (daclizumab) or with matching placebo in combination with cyclosporine, steroids, and mycophenolate mofetil. RESULTS: Treatment with anti-CD25 mAb affected the number of infiltrating CD3 and CD68 cells and the IL-2-regulated apoptotic pathway. During anti-CD25 mAb treatment, significantly lower intragraft IL-2 and CD25 mRNA transcription levels and decreased numbers of CD25+ T cells were found compared with the levels measured in endomyocardial biopsy specimens from placebo-treated patients (5- to 10-fold, P=0.002 and P<0.0001, respectively). In these samples the intragraft mRNA expression levels of IL-15 were also lower (P=0.02). Inhibition of the IL-2 pathway by anti-CD25 mAb therapy was accompanied by reduced mRNA and protein of Fas ligand and not by reduced Fas expression (P=0.001 and P=0.03). TUNEL staining revealed that the proportion of graft-infiltrating cells was lower in the anti-CD25 mAb patient group than the proportion of apoptotic cells in patients receiving placebo (P=0.06). CONCLUSION: Our data suggest that immunosuppressive agents that affect the IL-2 pathway hinder the mechanism of activation-induced cell death by which the immune system eliminates alloreactive cells.

Renal failure after clinical heart transplantation is associated with the TGF-beta 1 codon 10 gene polymorphism.

BACKGROUND: To determine whether genetic factors are involved in the development of renal dysfunction due to cyclosporine nephrotoxicity, we analyzed 2 polymorphisms in the signal sequence of the transforming growth factor (TGF)-beta 1 gene; codon 10 (Leu(10) --> Pro) and codon 25 (Arg(25) --> Pro). METHOD: Using sequence specific oligonucleotide probing, we analyzed both TGF-beta1 gene polymorphisms in cardiac allograft recipients (n = 168) who survived at least 1 year with minimal follow-up of 7 years. Patients received cyclosporine and steroids as maintenance immunosuppressive therapy. Renal dysfunction was defined as a serum creatinine > or = 250 micromol/liter. RESULTS: Renal dysfunction was observed in 2% (3/168) of the patients at 1 year, in 7% (11/160) at 3 years, in 12% (18/152) at 5 years, and in 20% (26/131) at 7 years post-transplantation. The genotypic distributions for TGF-beta1 codon 10 were 7% Pro/Pro, 61% Pro/Leu, and 32% Leu/Leu, and for codon 25 these percentages were 1% Pro/Pro, 12% Pro/Arg, and 87% Arg/Arg. We found an association between the TGF-beta 1 genotype encoding proline at codon 10 and renal dysfunction. At 7 years post-transplantation, 26% (23/89) of the patients with the heterozygous Pro/Leu or homozygous Pro/Pro genotype had renal dysfunction vs only 7% (3/42) of the patients with the homozygous Leu/Leu genotype (p = 0.017). For the TGF-beta1 codon 25 genotypes, we found no association between TGF-beta 1 genotypes and renal dysfunction. CONCLUSION: Our data support the hypothesis that TGF-beta 1 is involved in the process leading to renal insufficiency in cyclosporine-treated cardiac allograft recipients. In these patients the presence of TGF-beta 1 Pro(10) might be a risk factor.

[Laparoscopic donor nephrectomy for kidney transplants from living family members: good preliminary results]. / Laparoscopische donornefrectomie bij familieniertransplantaties; gunstige eerste ervaringen.

OBJECTIVE: Evaluation of safety and technical feasibility of laparoscopic live donor nephrectomy. DESIGN: Descriptive. METHOD: The per- and postoperative results were analysed of 15 patients subjected to laparoscopic live donor nephrectomy in the Erasmus Medical Centre Rotterdam, Dept. of General Surgery, the Netherlands. Both left and right nephrectomy were performed via the transperitoneal route. The kidney was removed via a subumbilical incision. RESULTS: Laparoscopic donor nephrectomy was attempted in 15 patients and completed successfully in 14. Conversion to flank incision was resorted to one patient because of a venous bleeding. Median operating time was 290 min (SD: 57). Mean warm ischaemia time was 7 min (range: 4-17), including laparoscopic harvest. All kidneys were functioning well after transplantation. The mean duration of postoperative hospitalization of the donors was 4 days. CONCLUSION: Laparoscopic live donor nephrectomy is a safe and technically feasible procedure in a kidney transplant programme involving a living relative.

Nephrocalcinosis as adult presentation of Bartter syndrome type II.

Bartter syndrome consists a group of rare autosomal-recessive renal tubulopathies characterised by renal salt wasting, hypokalaemic metabolic alkalosis, hypercalciuria and hyperreninaemic hyperaldosteronism. It is classified into five types. Mutations in the KCNJ1 gene (classified as type II) usually cause the neonatal form of Bartter syndrome. We describe an adult patient with a homozygous KCNJ1 mutation resulting in a remarkably mild phenotype of neonatal type Bartter syndrome.

Patients on chronic hemodialysis have no intrinsic lymphocyte defect upon stimulation with interleukin-2, interleukin-15 or tumor necrosis factor-alpha.

BACKGROUND: Patients on chronic hemodialysis (HD) suffer from general immune incompetence, resulting in a high incidence of infectious complications, impaired response to vaccinations and a high incidence of malignancy. Although various abnormalities in T cell function of HD patients have been described, it remains unclear whether this is due to an intrinsic T cell defect. AIM: In the present study we tested the capacity of T cells to proliferate upon stimulation with antigen-presenting cell and T-cell-derived cytokines. METHODS: The proliferation capacity of lymphocytes obtained from patients on HD and healthy controls was determined by measuring the proliferation of peripheral blood mononuclear cells (PBMC) after stimulation with rhIL-2, rhIL-15, rhTNF-alpha, or combination of those cytokines. In all samples the percentage of alpha/beta TCR-positive T cells was measured. RESULTS: After isolation of PBMC the percentage of T cells varied from 70% (before stimulation) to 80% (after stimulation). IL-2, IL-15 and TNF-alpha all induced PBMC proliferation, while the combination TNF-alpha plus IL-2 or TNF-alpha plus IL-15 appeared to be additive. No difference between PBMC from HD patients and controls was found. CONCLUSION: We conclude that lymphocytes from HD patients have no intrinsic defects in their proliferation capacity after stimulation with IL-2, IL-15 or TNF-alpha, in vitro, as the increase in counts per minute is predominant.

The influence of cholesterol on mortality after transplantation is age dependent.

There is still no consensus on the treatment of elevated serum cholesterol in patients with a renal transplant. In the general population treatment is age dependent. We studied the influence of serum cholesterol 1 year after transplantation in all 676 recipients of a kidney graft transplanted in Rotterdam that survived and functioned for at least 1 year. The other variables included in this analysis are: donor and recipient age and gender, original disease, race, number of HLA A and B mismatches, number of previous transplantations, postmortal or living related transplantation and transplantation year. At 1 year after transplantation the following variables were included: serum cholesterol, serum creatinine, proteinuria and hypertension. In the Cox proportional hazards analysis, serum cholesterol at 1 year after transplantation turned out to be an important, independent variable influencing patient failure. The influence was linear but there was interaction with recipient age. The negative influence of serum cholesterol on the RR for patient failure decreased with increasing recipient age. For example, the proportional increase in RR of a 20-year-old with a serum cholesterol of 12 mmol/l compared with that of a cholesterol of a patient with serum cholesterol of 6 mmol/l was 6. In a 60-year-old with a cholesterol of 12 mmol/l the proportional increase in RR was only 1.2 compared with a contemporary with a cholesterol of 6 mmol/l. Serum cholesterol levels have an independent influence on patient failure. The RR is influenced by recipient age, so that the negative effect of increasing cholesterol levels in the elderly is overruled by the RR of age and disappears.

Quantitative flow cytometry to measure the TNF-alpha and IL-2 system after heart transplantation.

After heart transplantation a high incidence of infections and malignancies is found. Not only immunosuppression, but also intrinsic cytokine systems with some unbalance, e. g. TNF-alpha and IL-2, can result in impaired immune competence and may have a role in these complications. The aim of this study was to assess the activity of the TNF-alpha and IL-2 systems after heart transplantation. In peripheral blood we measured expression of activation markers of TNF-alpha (TNF-R2) and IL-2 (IL-2R alpha, IL-2R beta-chain) on monocytes and lymphocytes using quantitative flow-cytometric analysis. TNF-R2 expression was significantly enhanced on monocytes and lymphocytes in patients after heart transplantation, while the expression of IL-2R alpha and IL-2R beta was not elevated. Increased TNF-R2 expression in peripheral blood after heart transplantation reflects an activated TNF-alpha system, leading to high levels of active sTNF-R, which impairs TNF-alpha bioavailibility and consequently leads to immune incompetence.

T cells activate the tumor necrosis factor-alpha system during hemodialysis, resulting in tachyphylaxis.

BACKGROUND: The immunosuppressive state of hemodialysis (HD) patients is accompanied by activation of antigen-presenting cell-derived cytokines, for example, tumor necrosis factor-alpha (TNF-alpha), which are required for T-cell activation. To test whether an activated TNF-alpha system results in impaired T-cell response in these patients, we analyzed parameters of their antigen-presenting cell (APC) function (for example, TNF-alpha system) and T-cell function [for example, interleukin-2 (IL-2) system]. METHODS: By quantitative flow cytometry, the expression of the TNF-receptor 2 (TNF-R2 = CD120b) and the alpha and beta chain of the IL-2 receptor (IL-2R; CD25, CD122) was measured. Using reverse transcriptase-polymerase chain reaction, the mRNA for TNF-alpha, IL-2, and IL-2R were determined. Phyto-hemagglutinin (PHA)- and IL-2-stimulated proliferation and cytokine production were measured. Biological activity of soluble receptors was measured by adding recombinant cytokines to the patient's plasma. RESULTS: CD120b expression was significantly increased in HD patients, whereas CD25 and CD122 was comparable to controls. In contrast to mRNA for IL-2 and IL-2R, mRNA for TNF-alpha was increased in HD. This resulted in significantly increased TNF-alpha levels in HD patients. In peripheral blood of HD patients, high levels of soluble TNF-R (R1 and R2) and IL-2R were found. These receptors were capable of binding 40% of added TNF-alpha and 55% of added IL-2. PHA-induced TNF-alpha production by T cells from HD patients was significantly lower, while their PHA-stimulated IL-2 production and proliferation capacity by T cells were comparable to controls. CONCLUSIONS: We conclude that although the TNF-alpha system is activated during HD, the TNF-alpha production of T cells is impaired, suggesting that tachyphylaxis of T cells occurs for TNF-alpha, as their proliferative capacity and IL-2 production capacity do not imply an intrinsic T-cell defect.