The detrimental effect of donor-specific antibodies is irrespective of its level in highly-immunized living donor kidney transplant recipients: A case-control series

Background

The impact of donor-specific antibodies (DSA) in (highly-) immunized living donor kidney transplant recipients is reported differentially in various patient cohorts.

Methods

We have performed a retrospective analysis of all consecutive HLA-incompatible living donor kidney transplant recipients in our center between 2010-2019. Recipients who underwent plasmafiltration for a positive CDC-crossmatch were excluded. For each DSA+ recipient (DSA+), one immunized recipient without DSA (pPRA+) and two non-immunized recipients (pPRA-) were included. Patient and graft survival were analyzed and a subgroup analysis of DSA+ recipients was performed.

Results

For 63 DSA+ recipients, 63 PRA+ and 126 PRA- recipients were included. 26 (41%) had class I, 24 (38%) class II and 13 (21%) combined HLA class I and II DSA. Death-censored graft survival was inferior in DSA+ recipients compared to pPRA+ (HR 2.38 [95% CI 1.00-5.70]) as well as to pPRA- (HR 3.91 [1.86-8.22]). In multivariate analysis, DSA remained of negative influence on death-censored graft survival. Flowcytometric crossmatch, MFI value, HLA class and origin of DSA were not of significant impact.

Conclusion

In our cohort of (highly-) immunized recipients, pretransplant DSA led to inferior death-censored graft survival. There were no "safe" DSA characteristics since only DSA per se impacted death-censored graft survival.

Living Donor Kidney Transplantation in a Patient With Epidermolysis Bullosa: A Case Report

Severe recessive dystrophic epidermolysis bullosa is a very rare inherited disease with excessive blisters forming starting at birth. Surgical intervention in this population creates a challenge: preventing formation of new lesions while managing previously scarred tissues. We present a case of a 27-year-old patient with end-stage renal disease caused by rapidly progressive IgA nephropathy. Living donor kidney transplantation was performed under local, spinal and epidural anesthesia. Living kidney transplantation in epidermolysis bullosa patients with end-stage renal disease should not be a contraindication for transplantation and should be considered as a viable and feasible option after careful preparation.

DCD donor hemodynamics as predictor of outcome after kidney transplantation

Insufficient hemodynamics during agonal phase-ie, the period between withdrawal of life-sustaining treatment and circulatory arrest-in Maastricht category III circulatory-death donors (DCD) potentially exacerbate ischemia/reperfusion injury. We included 409 Dutch adult recipients of DCD donor kidneys transplanted between 2006 and 2014. Peripheral oxygen saturation (SpO2-with pulse oximetry at the fingertip) and systolic blood pressure (SBP-with arterial catheter) were measured during agonal phase, and were dichotomized into minutes of SpO2 > 60% or SpO2 < 60%, and minutes of SBP > 80 mmHg or SBP < 80 mmHg. Outcome measures were and primary non-function (PNF), delayed graft function (DGF), and three-year graft survival. Primary non-function (PNF) rate was 6.6%, delayed graft function (DGF) rate was 67%, and graft survival at three years was 76%. Longer periods of agonal phase (median 16 min [IQR 11-23]) contributed significantly to an increased risk of DGF (P = .012), but not to PNF (P = .071) and graft failure (P = .528). Multiple logistic regression analysis showed that an increase from 7 to 20 minutes in period of SBP < 80 mmHg was associated with 2.19 times the odds (95% CI 1.08-4.46, P = .030) for DGF. In conclusion, duration of agonal phase is associated with early transplant outcome. SBP < 80 mmHg during agonal phase shows a better discrimination for transplant outcome than SpO2 < 60% does.

Kidney transplantation in patients declined by other centres

BACKGROUND

Transplant centres show considerable disagreement in the acceptance of transplant candidates with relative contraindications. The aim of this study is to investigate the outcomes of our patients who had been refused at other centres prior to transplantation at our centre.

METHODS

We included patients who had been excluded from transplantation or wait-listing at other centres before referral to our centre. We scored the reasons for refusal at other centres, the type of transplantation procedure, postoperative and long-term complications, patient and graft survival and how these patients experienced the transplantation and quality of life at our centre. All regular patients transplanted in 2010 functioned as a control group for outcome parameters.

RESULTS

We identified 23 patients in the period from January 2000 until March 2013. The most frequent reason for the refusal at other centres was obesity. Twenty of the 23 patients (87%) were alive and 19 had a functioning graft (83%) after a median follow-up of 21.0 months after transplantation (range 11.0-48.9). There were significantly more wound-related problems in the study group as compared with the control group (p = 0.029), but their kidney function at one year after transplantation was not significantly different. The patients indicated an improvement of quality of life after transplantation and in general were satisfied with the transplantation.

CONCLUSIONS

Patients who had previously had been denied transplantation at other centres generally did well after kidney transplantation with an increased risk of wound complications but a satisfactory graft and patient survival.

Kidney retransplantation in the ipsilateral iliac fossa: a surgical challenge

The aim of this study is to review the surgical outcome of kidney retransplantation in the ipsilateral iliac fossa in comparison to first kidney transplants. The database was screened for retransplantations between 1995 and 2013. Each study patient was matched with 3 patients with a first kidney transplantation. Just for graft and patient survival analyses, we added an extra control group including all patients receiving a second transplantation in the contralateral iliac fossa. We identified 99 patients who received a retransplantation in the ipsilateral iliac fossa. There was significantly more blood loss and longer operative time in the retransplantation group. The rate of vascular complications and graft nephrectomies within 1 year was significantly higher in the study group. The graft survival rates at 1 year and 3, 5, and 10 years were 76%, 67%, 61%, and 47% in the study group versus 94%, 88%, 77%, and 67% (p < 0.001) in the first control group versus 91%, 86%, 78%, and 57% (p = 0.008) in the second control group. Patient survival did not differ significantly between the groups. Kidney retransplantation in ipsilateral iliac fossa is surgically challenging and associated with more vascular complications and graft loss within the first year after transplantation. Whenever feasible, the second renal transplant (first retransplant) should be performed contralateral to the prior failed one.

Use of stenting in living donor kidney transplantation: does it reduce vesicoureteral complications?

The risk of urologic complications after kidney transplantation is 0% to 30%. We studied the impact of prophylactic stent placement during transplantation by assessing the necessity for a percutaneous nephrostomy (PCN) after living kidney transplantation. From January 2003 to December 2007, 342 living donor kidney transplantations were performed. Intra- and postoperative data were collected retrospectively from 285 patients with stent and 57 without. Baseline characteristics were not significantly different between groups, except for the number of previous transplantations: 31 (11%) patients with versus 16 (28%) without stent had a history of >1 transplantation (P < .001). From patients with PCN, 55 (87%) patients in the stented group received a PCN <3 months versus 11 (100%) in the nonstented group (P = .71). The reoperation rate for urologic complications was similar in both groups (3% (stented) versus 5% (nonstented; P = .43). In multivariate analysis, risk for PCN was similar in both groups (odds ratio 1.21, 95% confidence interval 0.5-2.5). Recipient survival was not significantly different. One- and 3-year death-censored graft survival was not significantly different between stented (89% and 84%) and nonstented group (90% and 85%, P = .71 and P = .96). Ureteral stent insertion is not associated with a reduced rate of PCN placement in living donor kidney transplantation.

KIR-ligand mismatches are associated with reduced long-term graft survival in HLA-compatible kidney transplantation

Natural killer (NK) cells are cytotoxic lymphocytes of the innate immune system with the ability to detect HLA class I disparities via killer-cell immunoglobulin-like receptors (KIR). To test whether such KIR-ligand mismatches contribute to the rejection of human solid allografts, we did a retrospective cohort study of 397 HLA-DR-compatible kidney transplantations and determined the KIR and HLA genotypes of recipients and the HLA genotypes of donors. In transplantations compatible for HLA-A, HLA-B and HLA-DR (n = 137), in which a role for T cells and HLA antibodies in rejection was minimized, KIR-ligand mismatches were associated with an approximately 25% reduction in 10-year death-censored graft survival (p = 0.043). This effect was comparable to the effect of classical HLA-A and HLA-B incompatibility, and in HLA-A,-B-incompatible transplantations (n = 260) no significant additional effect of KIR-ligand mismatches was observed. Multivariate Cox regression analysis confirmed the effect of KIR-ligand mismatching as an independent risk factor in HLA-A,-B,-DR-compatible transplantations (hazard ratio 2.29, range 1.03-5.10, p = 0.043). This finding constitutes the first indication that alloreactive NK cells may thwart the success of HLA-compatible kidney transplantations, and suggests that suppression of NK-cell activity can improve the survival of such kidney grafts.

Living kidney donors: impact of age on long-term safety

The safety of older live kidney donors, especially the decline in glomerular filtration rate (GFR) after donation, has been debated. In this study we evaluated long-term renal outcome in older live kidney donors. From 1994 to 2006 follow-up data of 539 consecutive live kidney donations were prospectively collected, during yearly visits to the outpatient clinic. Donors were categorized into two groups, based on age: < 60 (n = 422) and ≥ 60 (n = 117). Elderly had lower GFR predonation (80 vs. 96 mL/min respectively, p < 0.001). During median follow-up of 5.5 years, maximum decline in eGFR was 38% ± 9% and the percentage maximum decline was not different in both groups. On long-term follow-up, significantly more elderly had an eGFR < 60 mL/min (131 (80%) vs. 94 (31%), p < 0.001). However, renal function was stable and no eGFR of less than 30 mL/min was seen. In multivariate analysis higher body mass index (HR 1.09, 95%CI 1.03-1.14) and more HLA mismatches (HR 1.17, 95%CI 1.03-1.34) were significantly correlated with worse graft survival. Donor age did not influence graft survival. After kidney donation decline in eGFR is similar in younger and older donors. As kidney function does not progressively decline, live kidney donation by elderly is considered safe.

Altruistic donor triggered domino-paired kidney donation for unsuccessful couples from the kidney-exchange program

Between January 2000 and July 2009, 132 individuals inquired about altruistic kidney donation to strangers. These donors were willing to donate to genetically and emotionally unrelated patients. Some altruistic donors wished to donate to a specific person, but most wished to donate anonymously. In domino-paired donation, the altruistic donor donates to the recipient of an incompatible couple; the donor of that couple (domino-donor) donates to another couple or to the waiting list. In contrast to kidney-exchange donation where bilateral matching of couples is required, recipient and donor matching are unlinked in domino-paired donation. This facilitates matching for unsuccessful couples from the kidney-exchange program where blood type O prevails in recipients and is under-represented in donors. Fifty-one altruistic donors (39%) donated their kidney and 35 domino-donors were involved. There were 29 domino procedures, 24 with 1 altruistic donor and 1 domino-donor, 5 with more domino-donors. Eighty-six transplantations were performed. Donor and recipient blood type distribution in the couples limited allocation to blood type non-O waiting list patients. The success rate of domino-paired donation is dependent on the composition of the pool of incompatible pairs, but it offers opportunities for difficult to match pairs that were unsuccessful in the kidney-exchange program.

Successful expansion of the living donor pool by alternative living donation programs

Between January 2000 and December 2007, 786 potential recipients and 1059 potential donors attended our pretransplant unit with the request for a living-donor renal transplant procedure. The recipients brought one potential donor in 77.2% and two or more donors in 22.8% of cases. In the regular living donor program, a compatible donor was found for 467 recipients. Without considering alternative donation, 579 donors would have been refused. Alternative living donation programs led to 114 compatible combinations: kidney-exchange program (35), ABO-incompatible donation (25), anonymous donation (37) and domino-paired anonymous donation (17). Together, the 114 alternative program donations and the 467 regular living donations led to 581 living donor transplantations (24.4% increase). Eventually for 54.9% (581/1059) of our donors, a compatible combination was found. Donor-recipient incompatibility comprised 19.4% (89/458) in the final refused population, which is 8.8% of the potential donor-recipient couples. Without considering alternative donation, 30.1% (174/579) of the refused donors would have been refused on incompatibility and 6.4% (37/579) because they were anonymous. This is 20% of the potential donor population (211/1059). The implementation of alternative living donation programs led to a significant increase in the number of transplantations, while transplantations via the direct donation program steadily increased.

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.

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.

[Kidney transplantation: more kidneys from living donors, individualised immunosuppression and better results]

In the period 1996-2001, the number of transplanted postmortal kidneys decreased from 425 to 380, while at the same time the number of kidneys transplanted from living donors increased from 81 in 1996 to 155 per year in 2001. There was a striking increase in the proportion of living non-related donors (59/155). Although the short-term results of kidney transplantation have improved, and kidneys are very rarely lost as a consequence of acute rejection, the average life of a transplanted kidney has scarcely improved. Chronic allograft dysfunction is now the major cause of transplant loss. This process is hardly influenced by the immunosuppressive drugs currently used. To improve the cardiovascular risk profile, several centres discontinue the use of cyclosporin, tacrolimus or prednisone at 6 or 12 months after transplantation or substitute these with other drugs. This is complicated by acute rejection episodes in 10-20% of patients. With the arrival of a number of new immunosuppressive drugs the risk of rejection might be reduced.

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.

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.

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.

LONG-TERM GRAFT SURVIVAL AFTER UROLOGICAL COMPLICATIONS OF 695 KIDNEY TRANSPLANTATIONS

PURPOSE

We ascertain the incidence, management and long-term outcome of early urological complications requiring surgical exploration in kidney transplantation.

MATERIALS AND METHODS

Data of 695 consecutive kidney transplantations performed between January 1985 and January 1997 were assessed in regard to urological complications that occurred within 1 year after transplant. A computerized database was used to analyze graft recipient characteristics, the implantation procedure, complications and outcome in select patients and all those who underwent transplant during the same period. In the noncomplication group sufficient data for evaluation was available for 556 patients. We performed the Cox proportional hazards analysis with overall graft failure, graft failure or death as end points of observation.

RESULTS

Overall, 42 (6.0%) patients required revision of vesicoureteral anastomosis. Complications were identified after a median of 6 days (range 0 to 135). The primary reconstruction technique was extravesical in 64% and transvesical in 33% of patients, including 1 that involved ureteral Bricker anastomosis. Obstruction and/or leakage at vesicoureteral anastomosis accounted for 69% of urological complications. Revision was performed with a number of different reconstruction techniques. A second revision was required in 16.7%. Mean followup after primary transplant was 9.1 years (range 3.2 to 15). Multivariate analysis showed that surgical treatment of urological complication during year 1 after kidney transplantation did not increase the risk of overall graft failure, graft failure or death.

CONCLUSIONS

Our results indicate that long-term graft survival is not affected by a surgically treated urological complication.

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.

Renal graft survival in native and non-native European recipients

Most studies on the influence of recipient race on kidney transplant survival have been performed in the United States. Generally, they show a lower survival in African-Americans than in Caucasians. Since Rotterdam has gradually become a multi-ethnic society, we were able to study the effect of origin on kidney survival. We restricted our study to recipients of a primary cadaveric kidney graft between July 1983 and July 1997 who received cyclosporin as primary immunosuppression. Patients were divided into two main groups according to origin: European (n = 399) and non-European (n = 110). No statistical differences were found for mean donor age, sex distribution, or the total number of HLA-A and DR mismatches. Non-Europeans had significantly more mismatches on their HLA-B locus (P = 0.01) and recipient age was lower (P = 0.003). The reason non-Europeans had lost their native kidneys was more often hypertension and less often congenital or hereditary diseases compared to Europeans. The causes of death and of transplant failure did not differ. A multivariate Cox proportional hazards analysis did not show European or non-European origin to be an independent predictor of graft survival (two categories, P = 0.25). The variable origin in five categories did show an independent influence on graft survival, with Arab en African recipients running higher risks than European and Asian recipients. We conclude that, in our center, the prognosis after kidney transplantation is comparable for Europeans and non-Europeans; however, in the subcategories, Arab and African recipients have a worse prognosis.

The vanishing importance of age in renal transplantation

BACKGROUND

The growing number of patients awaiting a kidney transplant raises questions about allocation of kidneys to the elderly and about the use of elderly donors. In all reported studies analyzing the influence of age on the outcome after renal transplantation, age is investigated as a categorical variable.

METHODS

We studied age both as a categorical (Kaplan-Meier) and as a continuous (Cox) variable in a total of 509 cyclosporine-treated recipients of a primary cadaveric kidney graft who underwent transplantation between July 1983 and July 1997. For the Kaplan-Meier analysis, the population was divided into three comparably sized age groups: 17-43 years (n=171), 44-55 years (n=169), and 56-75 years (n=169).

RESULTS

Patient survival was better and graft survival censored for death was worse in the younger patients. Overall graft survival (end point was death or graft failure) was not significantly influenced by age. In the Cox proportional hazards analysis, transplantation year turned out to be an important, independent variable influencing all end points. Because the influence was not linear, three periods were defined in which the relative risk remained stable: 1983-1990, 1991-1993, and 1994-1997. In the second period, the relative risk for transplant failure or death was 49% of that in the first period. In the third period, the relative risk had decreased to 22% of that in the first period. Recipient age and donor age were significant predictors of overall transplant failure. There was no interaction between these variables and transplantation year. Within each transplantation period, an increase in recipient age by 1 year increased the relative risk for overall graft failure by only 1.44%. The influence of donor age followed a J-shaped curve with a minimum at 30 years. The influence of increasing either recipient or donor age was counteracted by the improving results over time.

CONCLUSION

Considering the improving results over time, there are, at this moment, no arguments for an age restriction for kidney transplant recipients or donors.

Decreased IgA1 response after primary oral immunization with live typhoid vaccine in primary IgA nephropathy

INTRODUCTION

Patients with primary IgA nephropathy (IgAN) have an increased level of immunological memory to certain parenteral recall antigens. We recently found a deficient IgA1 immune response after intranasal challenge with a neo-antigen: cholera toxin subunit B. In the present study, we assessed the specific IgA1 and IgA2 antibody response in plasma, peripheral blood cells and mucosal secretions after primary enteral immunization.

METHODS

Twenty eight IgAN patients, 26 patients with non-immunological renal disease and 32 healthy subjects were immunized orally with three sequential doses of live, attenuated, Salmonella typhi Ty21a. The humoral immune response in body fluids and antibody synthesis by circulating B cells was assessed in specific ELISAs and ELIPSAs respectively.

RESULTS

Oral immunization resulted in significantly (P<0.0001) increased IgM, IgG, IgA, IgA1 and IgA2 responses in all groups, both in plasma and in circulating B cells in vitro. The IgA1 response in plasma was significantly (P<0.05) lower in IgAN patients, while no significant differences in IgM (P=0.36), IgG (P= 0.79) or IgA2 (P=0.45) responses were found as compared with matched control groups. The amount of IgA1 synthesized by circulating B cells tended to be lower in IgAN patients. No significant IgA response after oral immunization with S. typhi Ty21a was found in saliva (P=0.11) or tears (P=0.10).

CONCLUSIONS

These data suggest an IgA1 hyporesponsiveness in patients with IgAN that is not only apparent after primary challenge of the nasal-associated lymphoid tissue but also after presentation to the gut. Previous results after parenteral recall immunization may be explained by assuming that IgAN patients require more frequent and/or longer exposure to IgA1-inducing antigens on their mucosal surfaces before they reach protective mucosal immunity. As a consequence, overproduction of IgA1 antibodies occurs in the systemic compartment, accompanied by an increased number of IgA1 memory cells.

[Acute kidney insufficiency in patients treated with fumaric acid esters for psoriasis]

We describe four female patients with psoriasis treated with fumaric acid esters. In two patients acute renal failure developed during this therapy. Histological investigation of renal biopsy in one patient was compatible with the diagnosis of acute tubular necrosis; her renal function was reversible after cessation of the medication. The histological diagnosis of the other patient was tubulo-interstitial nephritis, possibly as a reaction to acute tubular necrosis. The recovery of her renal function was incomplete after 9 months.