"Suboptimal" kidney donors: the experience with tacrolimus-based immunosuppression

Kidney transplantation with allografts from infant donors-Small organs, big value

BACKGROUND

Although infant organ donors remain a rare source of organs for transplantation, technical challenges have resulted in increased rates of complications and inferior graft function. The aim of the present study was to investigate the outcomes of kidneys procured from juvenile and infant donors.

PATIENTS AND METHODS

We evaluated all kidney transplants from deceased donors < 16 years of age performed at our center between 01/2008 and 08/2019. We defined three groups based on quartiles of donor body weight: <13 kg (infant donors), 13-40 kg (juvenile donors), and > 40 kg (standard criteria donors). Clinical characteristics and outcomes were compared between groups.

RESULTS

Ninety-two transplants were included in this study. Out of 92 recipients, there were 32 (34.8%) adult and 60 (65.2%) pediatric patients. All groups demonstrated excellent graft function and survival on both short and long-term follow-up. 1-year, 3-year, and 5-year graft survival rates for the standard criteria donor group were 100%, 95.2%, and 88.4%, respectively, compared with 95.8% for infant and 95% for juvenile donors at all times (P = .79). eGFR at 5 years was 98.9 ± 5.5, 74.1 ± 6.2, and 81.6 ± 6.9 mL/min/1.73 m² for infant, juvenile, and standard criteria donors, respectively (P < .01).

CONCLUSION

Infant donor allografts can be transplanted with excellent long-term outcomes in both pediatric and adult recipients. Implanting them as single allografts onto pediatric candidates allows for the transplantation of two patients. As such, pediatric recipients should be prioritized for these donor organs.

African-American race modifies the influence of tacrolimus concentrations on acute rejection and toxicity in kidney transplant recipients

STUDY OBJECTIVE

To determine the effect of tacrolimus trough concentrations on clinical outcomes in kidney transplantation, while assessing if African-American (AA) race modifies these associations.

DESIGN

Retrospective longitudinal cohort study of solitary adult kidney transplants.

SETTING

Large tertiary care transplant center.

PATIENTS

Adult solitary kidney transplant recipients (n=1078) who were AA (n=567) or non-AA (n=511).

EXPOSURE

Mean and regressed slope of tacrolimus trough concentrations. Subtherapeutic concentrations were lower than 8 ng/ml.

MEASUREMENTS AND MAIN RESULTS

AA patients were 1.7 times less likely than non-AA patients to achieve therapeutic tacrolimus concentrations (8 ng/ml or higher) during the first year after kidney transplant (35% vs 21%, respectively, p<0.001). AAs not achieving therapeutic concentrations were 2.4 times more likely to have acute cellular rejection (ACR) as compared with AAs achieving therapeutic concentrations (20.8% vs 8.5%, respectively, p<0.01) and 2.5 times more likely to have antibody-mediated rejection (AMR; 8.9% vs 3.6%, respectively, p<0.01). Rates of ACR (8.3% vs 6.7%) and AMR (2.0% vs 0.9% p=0.131) were similar in non-AAs compared across tacrolimus concentration groups. Multivariate modeling confirmed these findings and demonstrated that AAs with low tacrolimus exposure experienced a mild protective effect for the development of interstitial fibrosis/tubular atrophy (IF/TA; hazard ratio [HR] 0.78, 95% confidence interval [CI] 0.47-1.32) with the opposite demonstrated in non-AAs (HR 2.2, 95% CI 0.90-5.1).

CONCLUSION

In contradistinction to non-AAs, AAs who achieve therapeutic tacrolimus concentrations have substantially lower acute rejection rates but are at risk of developing IF/TA. These findings may reflect modifiable time-dependent racial differences in the concentration-effect relationship of tacrolimus. Achievement of therapeutic tacrolimus trough concentrations, potentially through genotyping and more aggressive dosing and monitoring, is essential to minimize the risk of acute rejection in AA kidney transplant recipients.

Can only histological evaluation determine the allocation of ECD kidneys?

INTRODUCTION

There is a recent debate on the "transplantability" of ECD (Expanded Criteria Donors) kidneys and the selection criteria used to allocate them to single or double transplantation. Remuzzi et al. have defined a protocol incorporating pre-transplant donor biopsy to guide the use of older donor organs. They allocated organs as single or double transplants on the basis of histological findings. We aim to show the pros and cons of the only histological evaluation in the allocation of ECD kidneys, to compare the different experiences in United States and Europe and thus to discuss whether this tool should be used alone or included in a comprehensive clinical and histopathological evaluation.

DISCUSSION

In the United States many Authors stated that the biopsy actually increases the percentage of kidney discarded and they raised questions about the importance of the biopsy in evaluating ECD kidneys for transplantation. On the other hand, the experiences of the majority of european transplant centers showed that allocating kidneys as single or dual transplant based on biopsy findings may achieve good graft and patient outcomes. Moreover, the experience of some centers as ours showed that kidneys allocated as DKT (Dual Kidney Transplant) on the basis of Remuzzi's score could have been suitable for single transplantation suggesting the need of an adjustment of the Remuzzi Score System. Many Authors, who are in favor of histological evaluation, actually believe that a comprehensive clinical and histopathological assessment before transplantation remains necessary. We lack precise national- or international-based selection criteria to guide clinicians. An adjustment of the Remuzzi Score System could be taken into consideration such as narrowing the indication for DKT from those ECD kidneys with higher scores and including the histological evaluation in a multifactor score.

Pediatric en bloc kidney transplantation to adult recipients: more than suboptimal?

BACKGROUND

To optimize available organs, kidneys from young donors traditionally believed to be suboptimal are transplanted to adults. The purpose of this study is to compare graft survival (GS) of en bloc kidney (EBK) from young pediatric donors to other deceased donor transplants in adult recipients.

METHODS

We analyzed United Network of Organ Sharing/STAR data on primary deceased donor kidney transplants to adult recipients (1988-2006). EBK (age younger than 5 years, n=1696) was compared with solitary pediatric (SP; age younger than 5 years) kidneys (n=1502), and matched standard adult donors (age 18-59 years, n=9594) and expanded criteria donor (ECD; n=6396). The adjusted GS was obtained using Cox proportional hazard model and hazard ratios were calculated.

RESULTS

EBK had lowest acute rejection rates (6.0%) but similar to standard adult transplants (6.3%), and lower than SP and ECD (9.0% and 8.2%; P<0.0001). Delayed graft function rates were lowest in EBK (17.9%), highest in ECD (34.8%; P<0.0001), and similar among SP and standard adult transplants (24.4% and 24.2%). The estimated glomerular filtration rate (eGFR) was best in EBK and worst in ECD (P<0.0001). The eGFR of EBK and SP transplants continuously improved but the eGFR of standard adult and ECD declined. Graft loss was higher in EBK and SP transplants than adult donor transplants during the first 6 months. Despite the highest thrombosis rates in EBK (5.0%) (SP, 3.3%; standard adult, 1.8%; ECD, 2.0%, P<0.0001), GS of EBK became similar to standard adult donor transplants by 5 years and best at 10 years posttransplant (64.0%) and worst in ECD (39.6%; P<0.0001).

CONCLUSION

EBK had the best long-term outcomes among deceased donor transplants and offer unique options for adult kidney transplant recipients.

Calcineurin inhibitor-free immunosuppression in dual kidney transplantation from elderly donors

BACKGROUND

Kidneys from expanded-criteria donors may be particularly susceptible to calcineurin inhibitor (CI)-mediated vasoconstriction and nephrotoxicity. In the early post-transplant phase, using CI may prolong ischemic injury and, in the long term, chronic CI nephrotoxicity is an even greater concern. To avoid the acute and chronic consequences of CI in kidneys from marginal donors, CI-free protocols have been introduced for maintenance immunosuppressive therapy. A CI-free protocol of anti-thymocyte globulin (ATG) induction, sirolimus, mycophenolate mofetil (MMF) and steroids has been adopted at our center in recipients of dual kidney transplantation (DKT) from elderly donors (EDs).

METHODS

Dual kidney transplantations performed since April 2003 on CI-free immunosuppression (group 1 = 31) were compared with earlier DKTs in recipients treated with CI-based therapy (group 2 = 25), retrospectively analyzing patient and graft survival, surgical and medical complications, rejection episodes and renal function.

RESULTS

No deaths occurred after a mean follow-up of 10.1 +/- 7.6 (group 1) and 48.2 +/- 17.4 months (group 2). Graft loss occurred in one patient in group 1 (bilateral renal vein thrombosis) and in three patients in group 2 (one primary non-function [PNF], one chronic rejection, one Kaposi's sarcoma). The incidence of acute rejection was 19% in group 1 and 16% in group 2. Delayed graft function (DGF) was recorded in 16% and 48%, respectively. Renal function was better in group 1, with a mean S-Cr of 135 +/- 48 vs. 210 +/- 141 micromol/L at one month and 116 +/- 30 vs. 149 +/- 49 micromol/L at six months.

CONCLUSIONS

After DKT from EDs, a CI-free immunosuppressive regimen including ATG induction, sirolimus, MMF and steroids affords excellent results, with a lower DGF rate and a better renal function.

Outcome of renal transplants from pediatric donors <5 yr of age

AIM

Outcomes of single renal transplants from donors <5 yr old have traditionally been inferior to those from older donors. We retrospectively studied our experience with patients who received renal transplants, either individually or en bloc, from young donors (<5 yr of age) to determine the utility of these organs. We also compared the outcomes of these transplant patients maintained on either cyclosporine- (CyA) or tacrolimus-based (TRL) immunosuppression regimens.

PATIENTS

Ninety-eight patients received transplants at our center from donors <5 yr of age between August 1993 and August 2003. They were followed-up from 12 months to 11 yr. Patients were divided into four groups based on whether they received single or en bloc transplants, and whether CyA or TRL was the base immunosuppressive agent. Patients in group I (n = 13) received single pediatric kidneys and were treated with CyA regimens; group II patients (n = 26) also received single pediatric kidneys, but were treated with TRL regimens; group III patients (n = 31) were transplanted en bloc and were treated with CyA; and group IV patients (n = 28) received en bloc transplants and were treated with TRL.

RESULTS

One-year patient and death-censored graft survival was not significantly different between recipients of en bloc vs. single grafts (i.e. 88 and 85% vs. 90 and 87%, respectively), or between the four treatment groups (group I: 85 and 85%, group II: 92 and 88%, group III: 87 and 84%, and group IV: 89 and 86%, respectively). The overall 1-yr rejection rate was 30% (29 of 98), which was significantly higher in the CyA-treated patients 19 of 44; i.e. 43%, than in TRL-treated patients 10 of 54, i.e. 19%, p = 0.03). In the en bloc recipients, seven grafts (12%) were lost as a result of vascular thrombosis. Notably, none of the single kidneys were lost because of vascular thrombosis. At the end of follow-up the creatinine levels of both groups were comparable.

CONCLUSIONS

Pediatric donor kidneys transplanted individually provide for equal patient and graft survival when compared with en bloc transplants. TRL can be used reduce the detrimental effect of acute rejection on graft growth and function when compared with CyA. Single use of such kidneys can safely and efficaciously be transplanted into adult recipients, greatly expanding the donor pool.

Tacrolimus/mycophenolate mofetil-based immunosuppression in aged kidney transplant. A prospective study

BACKGROUND

At the moment, controversy has arisen about immunosuppression in aged kidney transplant recipients. We present our results on the efficacy and safety of induction treatment based on tacrolimus (FK506) and mycophenolate mofetil (MMF).

MATERIAL AND METHOD

We performed 72 transplants in patients of 60 years or older. Induction treatment consisted on (FK 506) 0.1 mg/kg/day and MMF 2 gr/day. Antilymphocyte serum was administered with delayed graft function. A total of 54 patients received kidneys from donors over 60 years old.

RESULTS

Cold ischemia time was 16.4 h (S=5.7). Delayed graft function occurred in 35 patients (48.6%). Acute rejection was observed in nine patients (12.5%). Opportunistic infections were found in 19 patients (26.4%). Seven patients died due to sudden death (1), acute myocardial infarction (1), stroke (1), infection (3), and neoplasm (1). At 1, 2, and 3 years, serum creatinine was 145, 163, and 156 mmol/l; patient survival 93%, 90%, and 90%; graft survival 93%, 90%, and 87%; and death-censored graft survival 100%, 100%, and 97%, respectively.

CONCLUSION

These immunosuppressive guidelines appear to be efficacious and safe in kidney transplant in elderly recipients.

En-bloc kidney transplantation in the United states: an analysis of united network of organ sharing (UNOS) data from 1987 to 2003

With increasing donor organ shortages, en-bloc kidney (EBK) transplantation is an alternative to utilize very young or very old donor age cadaver kidneys for transplantation. Several single-center series have reported excellent graft survival (GS). We sought to determine national level registry-based patterns for GS and determine adjusted hazard ratios (AHR) for graft loss after EBK versus single kidney (SK) cadaver transplants. Data reported to UNOS from 1987 to 2003 were analyzed using PHREG (SAS version 8.1) statistical procedures. Proportional hazards models were constructed that included multiple donor, recipient and surgical variables. Of the 2160 EBK transplants reported, 77% were from donors < 5 years of age. EBK transplants had superior GS to SK transplants, when donor age was restricted to < 5 years (AHR 0.708, p < 0.001). GS at 1, 3 and 5 years post-transplant was superior with EBK (85%, 76% and 71%) versus SK (81%, 68%, 63% and p < 0.001 at all time points). EBK transplants from very young donors were associated with a significantly lower rate of delayed graft function than SK transplants (17.9% versus 23.4%, p < 0.001). National registry data suggest that EBK transplants present a viable option for transplantation of very young donor kidneys.

Alterations of the immune response with increasing recipient age are associated with reduced long-term organ graft function of rat kidney allografts1

BACKGROUND

Clinically, an increasing number of older recipients are listed for transplantation. We examined recipient age-associated alterations of the immune response and their effects on graft function.

METHODS

Three- and 18-month-old Lewis (LEW) rats received kidneys from 3- and 18-month-old Fischer 344 (F344) rats (1.5 mg/kg/d cyclosporine A for 10 days; n=6/group) and were observed for 180 days. In additional groups, double kidney transplantations were performed to determine the impact of nephron mass and recipient age on graft outcome.

RESULTS

All young recipients but only 66% of old recipients survived the observation period. Increasing recipient age resulted in a significant decrease in renal allograft function (P<0.001), more advanced morphologic evidence of chronic allograft damage (P<0.001), and greater cellular infiltration (P<0.05) and major histocompatibility complex expression (P<0.01) within grafts. Additional in vitro studies examined age-related changes in the cellular immune response by enzyme-linked immunosorbent assay, fluorescence-activated cell sorter analysis, and alloreactive enzyme-linked immunospot: splenocytes from old LEW rats produced significantly more interleukin (IL)-2 (P<0.0001), IL-4 (P<0.05), interferon (IFN)-gamma (P<0.0001), and tumor necrosis factor-alpha (P<0.05). IFN-gamma-producing memory-type T cells were significantly elevated in older rats (P<0.0001). Moreover, they revealed significantly more alloreactive T cells directed against F344 (146 +/- 64.2 and 512 +/- 277/10(6) T cells; P<0.05). Double renal allografts from young donors into old recipients confirmed an independent effect of recipient age on the acceleration of chronic graft deterioration.

CONCLUSIONS

The enhanced cellular immune responsiveness in elderly recipients was associated with advanced chronic graft injury. Clinically, older recipients may need a modified immunosuppression.

Outcome of 3 years of immunosuppression with tacrolimus in more than 1,000 renal transplant recipients in japan

BACKGROUND

In Japan, the new macrolide immunosuppressant, tacrolimus, was approved for the prevention and treatment of allograft rejection in renal transplant recipients in April 1996. This article summarizes efficacy and safety data for tacrolimus gathered since its approval.

METHOD

Data from 1,007 patients who received tacrolimus-based treatment after kidney transplantation at 35 leading Japanese transplant centers between April 1996 and December 2000 were retrospectively analyzed.

RESULTS

The renal transplants consisted of 856 living (756 ABO compatible, 100 ABO incompatible) and 151 cadaveric (146 non-heart-beating, 5 brain dead) donor grafts. Mean follow-up duration was 24.4 months. Overall patient and graft survival rates were 98.4% and 94.8% at 1 year, 98.0% and 92.6% at 2 years, and 97.6% and 90.4% at 3 years, respectively. Graft survival rates in living and non-heart-beating donor graft transplantations were 95.9% and 88.8% at 1 year, 94.0% and 85.0% at 2 years, and 92.2% and 80.0% at 3 years, respectively. Graft survival rates in living ABO-compatible donor graft transplantation ranged from 93.4% to 97.5%, and in ABO-incompatible cases, rates were stable at 83.2% throughout the 3-year assessment period. Median serum creatinine levels ranged from 1.30 to 1.37 mg/dL during this time. Percentages of patients receiving antihyperlipidemics, antihypertensives, and insulin were 12.6%, 41.1%, and 6.5% at 1 year, respectively, and remained low at 3 years after transplantation.

CONCLUSION

Three years of tacrolimus therapy demonstrated excellent efficacy and safety in more than 1,000 renal transplant recipients, including recipients of living ABO-incompatible and non-heart-beating donor grafts, with favorable graft function maintained.

The marginal kidney donor

In parallel with increased clinical demand, less than optimal or so-called marginal kidney grafts are being used for transplantation. In addition to donor age, it appears that several factors may impact negatively on the quality of the graft. Most importantly, a more precise definition of the term 'marginal graft' is needed. The present review analyzes potential risk factors, suggests scoring systems for a more precise definition, and discusses potential treatment options to improve the quality of marginal grafts.

Does renal mass exert an independent effect on the determinants of antigen-dependent injury?

The aim of this retrospective study was to determine whether nephron mass may exert a direct, independent effect on immunological tolerance. To this end, data corresponding to patients transplanted with en block pediatric kidneys (EBPK) (n=48) were compared with those of renal transplants with a low risk of hyperfiltration (LRH) comprised of recipients of a kidney from young donors (age 5-40 years) (n=173), and transplants with a high risk of hyperfiltration (HRH) comprised of patients who had received a graft from an elderly donor (older than 55 years) (n=91). All the patients had been subjected to the same immunosuppressive treatment. The median follow-up period was 54 months (6-127 months). The EBPK group showed lowest serum creatinine and highest creatinine clearance levels at each follow-up time. The rate of proteinuria >500 mg/day was 5.7% in EBPK, 7.4% in LRH, and 27.3% in HRH (P=0.000). The incidence of acute corticoresistant rejection was minor in EBPK (7.0% in EBPK, 21.3% in LRH, and 23.3% in HRH; P=0.04). Logistic regression analysis showed that the type of transplant was predictive of acute corticoresistant rejection [RR 5.33 (95% confidence interval (CI) 1.15-24.62) for HRH and RR 4.75 (95%CI 1.06-21.27) for LRH, P=0.03]. Multivariate analyses for graft failure due to chronic rejection and for graft failure due to acute rejection according to Cox's regression analysis demonstrated that HRH transplant was a significant predictive variable of both types of failure [4.08 (95%CI 1.27-13.04) for graft loss due to chronic rejection and 8.69 (95%CI 1.69-44.67) for graft loss due to acute rejection]. The present stratification of data according to nephronal mass would appear to indicate that the greater the mass, the lower the incidence of both acute and chronic rejection. This finding lends support to the hypothesis that a large mass of transplanted tissue relative to recipient mass may dampen the immune response.

Permanent detrimental effect of nonimmunological factors on long-term renal graft survival: a parsimonious model of time-dependency

PURPOSE

We attempted to model and test the pattern of effects of prognostic factors on renal graft survival during the posttransplantation time course.

PATIENTS AND METHODS

Patients who received a cadaveric kidney-only transplant between January 1990 and December 1995 in Eurotransplant, who received cyclosporine as induction therapy, and who had a complete follow-up at the time of analysis were included in the study (n= 10614). An index summarizing all covariate information was calculated and used for modeling the time-dependent effects with relation to graft failure.

RESULTS

The immunological factors (HLA mismatch and % panel-reactive antibody) were seen to have a slowly decreasing negative effect on renal graft survival. The cold ischemic trauma (>24 hr) exerted a permanent detrimental effect on the grafts. The use of organs obtained from old donors was associated with a constant higher risk of graft loss.

CONCLUSIONS

An analysis of determinants of human allograft dysfunction should also study the interaction between the effects and time. Nonimmunological factors had a constant detrimental effect on graft failure, whereas the impact of the immunological factors--although remaining important for late graft loss--very slowly decreased. In the context of marginal transplants, clustering of unfavorable factors should be avoided to prevent late graft losses.

Double versus single renal allografts from aged donors

BACKGROUND

The age limit of the cadaver kidney donors is increasing in response to the growing demand for renal transplantation. Simultaneous double kidney transplantation (SDKT) with kidneys obtained from elderly adults has been proposed to increase the transplantation number and improve its results. However, if SDKT is performed when there are no clear indications, a negative effect could be produced on the total number of transplanted patients as both kidneys would be used for only one recipient.

MATERIAL AND METHODS

In December 1996 we designed a transplantation protocol to be able to extend the selection of cadaver kidney donors with normal serum creatinine levels without establishing any age limit. A pregraft renal biopsy was always performed to analyze the glomerulosclerosis (GE) percentage whenever the donors were 60 years of age or older. A SDKT was performed in a single recipient when the donor age was 75 years or older or when the donors between 60 and 74 years old had a GE rate of more than 15%. On the contrary, a single kidney transplantation was performed in two different recipients for kidneys from donors between 60 and 74 years of age with a GE rate of less than 15%. Kidneys having GE rates of more than 50% were discarded for transplantation. Donor kidneys from subjects younger than 60 years of age were always used for a single kidney transplantation.

RESULTS

Based on the above mentioned protocol, from December 1996 to May 1998, 181 patients received a kidney transplantation in our hospital. These patients were divided into three groups: group I which included the SDKT recipients (n=21), group II or single kidney recipients from 60- to 74-year-old donors (n=40), and group III or recipients from <60-year-old donors (n=120). The mean follow-up time was 15+/-5 months (range 6-24). Mean donor age was 75+/-7 years in group I, this was significantly higher than in group II (67+/-4, P<0.001) and group III (37+/-15, P<0.001). The primary nonfunction rate was low in the three groups, there being no statistically significant differences (5, 5, and 4%, respectively). A significantly greater percentage of patients from group I (76%) presented immediate renal graft function as compared with group II (43%, P<0.01) and III (50%, P<0.05). The acute rejections rate was very low in all three groups (9.5, 7.5, and 22%, respectively) with significant differences between groups II and III (P<0.05). No significant differences between the different groups were observed for one year actuarial patient survival (100, 95, and 98%, respectively) or graft survival rates (95, 90, and 93%, respectively). The 6-month serum creatinine levels were excellent in the three groups, although there were significant differences between groups I and II (1.6+/-0.3 vs. 1.9+/-0.6 mg/dl, P<0.05), II and III (1.9+/-0.6 vs. 1.4+/-0.4 mg/dl, P<0.001), and I and III (P<0.05).

CONCLUSIONS

Simultaneous double kidney transplantations make it possible to use kidneys from extremely elderly donors (>75 years) or those whose GE>15%. In addition, kidneys from donor 60-74 years old in which the GE<15% can be used for single kidney transplantations in two different recipients with excellent results.

Biopsy of marginal donor kidneys: correlation of histologic findings with graft dysfunction

BACKGROUND

Kidney biopsies are being used to evaluate marginal donors, but rigorous statistical validation of this practice with multivariate analysis has not been performed.

METHODS

To analyze histologic parameters in 78 donor biopsies for their ability to predict graft dysfunction, we used a proportional odds model that included both donor and recipient factors. Glomerulosclerosis was categorized into grades 0, 1, 2, and 3, corresponding to 0, 1-10%, 11-20%, and 21-30% global sclerosis, respectively. The degrees of interstitial fibrosis, tubular atrophy, arteriosclerosis, and arteriolar hyalinosis were graded from 0 to 3+, using definitions suggested by the Banff Schema of allograft pathology.

RESULTS

Increasing donor age was associated with higher glomerulosclerosis, tubular atrophy, and arteriosclerosis. Kidneys with any degree of interstitial fibrosis were 2.6 times [odds ratio (OR)] more likely to experience a worse outcome at 6 months (P = 0.02). This association held up after correction for acute rejection (OR 2.5, P = 0.03) and high panel-reactive antibody (OR 3.4, P = 0.006), However, the OR was reduced to 1.9 (P = 0.15) after controlling for recipient age. With each increment in the grade of glomerulosclerosis, the odds for a worse outcome at 12 months increased to 2.3 (P = 0.005). The value for OR became 2.0 (P = 0.03) when controlling for recipient age (P = 0.01), 2.4 (P = 0.005), when controlling for acute rejection, and 2.3 (P = 0.006) when controlling for high panel-reactive antibody.

CONCLUSIONS

Histopathological parameters present in donor biopsies can independently predict post-transplant graft function. Implications for the pool of donor organs available for transplantation are discussed.

Newer immunosuppressive drugs: a review

In recent years, many new immunosuppressive drugs have been discovered and developed for clinical use in transplantation. This review focuses on those drugs (leflunomide, mycophenolate mofetil, sirolimus, tacrolimus) that have been shown to have immunosuppressive activity in patients. Different anti-interleukin-2 receptor antibodies are also reviewed as an example of a resurgence of development in the area of monoclonal antibodies. The price for reducing the incidence of allograft rejection by improved immunosuppression was thought to be a proportional increase in the incidence of infection and malignancy. Data from Phase III clinical trials of new immunosuppressants, however, show a statistically significant reduction in the incidence of acute rejection produced by these new drugs, which has not been accompanied by increases in infection and malignancy rates. The wide array of new drugs offers the opportunity to use combinations that block different pathways of immune activation while at the same time selecting drug combinations with nonoverlapping toxicity profiles so that doses of each single drug can be reduced below toxicity levels. The immunosuppressive therapy for patients can be tailored according to their individual needs.

Renal transplantation in recipients over the age of 60: the impact of donor age

BACKGROUND

Kidneys from older donors exhibit a series of changes characterized by glomerular, vascular, and tubular senescence. These changes may be aggravated by atherosclerosis, hypertension, or diabetes, which are highly prevalent in older individuals.

METHODS

We analyzed the outcome after transplantation in 230 recipients over the age of 60, who received transplants between February 1990 and December 1996. We assessed the 1- and 5-year patient and graft survival, the quality of renal function, tacrolimus levels, the incidence of rejection, and the incidence of delayed graft function, and compared the outcomes in recipients of kidneys from donors over the age of 60 (group 1, n = 40) with those in recipients of kidneys from donors under the age of 60 (group 2, n = 190). There were no differences between the two groups in terms of recipient sex, race, age, and cold ischemia time. Immunosuppression was with tacrolimus and steroids in 61% of cases; in the remainder of the patients, a third agent, either azathioprine, cyclophosphamide (for 1 week), or mycophenolate mofetil was administered as well. The median follow-up was 31.5 months (range: 1-86).

RESULTS

In recipients over the age of 60 receiving tacrolimus-based immunosuppression, overall patient survival at 1 and 5 years was 90% and 76%, and was not significantly compromised in recipients receiving a kidney from a donor over the age of 60. The overall 1-and 5-year actuarial graft survival was 84% and 64%; in recipients from donors over the age of 60, it was 73% and 52%, whereas in recipients of kidneys from donors under the age of 60, it was 87% and 66% (P<0.05). Most of the effect on graft survival was seen by 1 year. The mean serum creatinine was 2.6+/-2.7 mg/dl, without any difference between the two groups. Although the incidence of delayed graft function was higher in recipients of kidneys from donors over the age of 60, this difference did not reach statistical significance.

CONCLUSIONS

Although the overall outcomes of transplantation in older recipients remain reasonable, the inferior outcomes with older donor kidneys call into question proposals to utilize older donor kidneys preferentially in older recipients.

High-risk donors: expanding donor criteria

Advances in the surgical techniques, preservation solutions, and methods for predicting eventual long-term renal function from expanded donors will be critical in allowing precise selection criteria for kidneys for transplantation, resulting in the optimum use of a scarce and precious resource. Until other options such as xenotransplantation or tissue engineering become realistic, the challenge for the millennium will be to identify which donor organs previously considered suboptimal can be safely used to expand the organ donor pool.

Renal transplantation with limit donors: to what should the good results obtained be attributed?

BACKGROUND

With the aim of offsetting the reduction in donors of kidneys for transplantation, we extended the acceptance criteria, considering donors over 60 years old.

METHODS

The results obtained in 84 transplants carried out with this type of donor (group A) was compared with those of a control group of 125 transplants carried out with kidneys from donors under 60 years old (group B). The protocol for selection of donors was appropriate creatinine clearance, minimum proteinuria, and normal renal scan. The histological study was not included because it was not considered appropriate to assess the extent of the possible glomerulosclerosis, as this has a focal, segmented distribution. There were no significant differences between the recipients except for age (57.8 years old in group A vs. 39.2 years in group B).

RESULTS

After the transplantation, there were significant differences in the duration of hospitalization (26.8 days vs. 21.8 days, P<0.009), annual plasma creatinemia (177, 225, 233, 235, and 205 micromol/L vs. 136, 150, 121, 111, and 133 micromol/L, P<0.0002/0.0004), graft survival (87%, 85%, 81%, 81%, and 81% vs. 89%, 88%, 86%, 86%, and 85%, P<0.03), and patient survival (92%, 89%, 85%, 85%, and 85% vs. 99%, 99%, 97%, 96%, and 95%, P<0.0004). Death of the patient was the only significantly more frequent cause of graft loss among group A patients (7 vs. 1 death, P<0.004). No kidney was "never working" and none were lost because of chronic rejection.

CONCLUSIONS

It was concluded that elderly donors should be considered as suitable for transplantation irrespective of their chronological age, provided that they fulfill the acceptance criteria. The quality of life achieved was comparable in both groups. Despite the lower renal function in group A, this remained constant during the follow-up period.

En bloc transplantation of infant kidneys: ten-year experience

BACKGROUND

Recent data have shown that en bloc infant kidneys transplanted to adult recipients functioned well. Longterm graft survival and function are not available, however. This study analyzes the 10-year experience with transplantation of en bloc infant kidneys from 1987-1997.

STUDY DESIGN

This is a chart review of adult recipients of en bloc infant kidneys with respect to donors' and recipients' age, weight, creatinine, HLA antigen matching, panel reactive antibodies, cold ischemia time, surgical complications, original disease, and longterm graft function and survival.

RESULTS

Five en bloc kidneys thrombosed (6.4%). Two ureteral fistulas were repaired successfully. Five patients underwent dialysis (6.4%). Two patients died of infection, six of heart attack and stroke, and one of cancer. All had excellent graft function at patients' death. Renal artery stenosis was dilated in seven patients. Six grafts were lost to rejection (one from noncompliance at 20 months). The original disease recurred in three patients with massive proteinuria despite excellent function. Graft survival at 43 months (range, 6-123 months) was 79%, with serum creatinine levels at 1, 3, 9 and 10 years of 1.2, 1.0, 0.8 and 0.8 mg/dl, respectively. Creatinine clearance averaged 88 mL/min (range, 34-188 mL) and 24-hour proteinuria was 146 mg (normal range, 10-150).

CONCLUSIONS

In conclusion, en bloc infant kidneys can be transplanted successfully with excellent longterm function, hyperfiltration injury was not observed, and infant kidneys should be used more frequently.

Renal transplantation: surgical aspects, complications and results

Despite the fact that kidney transplants have routinely been successfully performed for over 30 years there continues to be challenges for the transplant surgeon. These include a static donor pool, growing recipient list, declining number of ideal donors and greater reliance on marginal donors. Innovative methods to deal with these problems continue to be sought.