Immunosuppression: evolution in practice and trends, 1994-2004

Renal transplantation in the elderly

Elderly patients are increasingly being considered for kidney transplantation due to a global explosion of the aging population with end-stage renal disease (ESRD). However, mounting scarcity of available organs for transplant has led to a wider disparity between organ supply and demand. Consequently, the criteria for accepting kidneys for transplantation have been extended in an attempt to allow the use of organs from elderly donors or those with significant co-morbidities, so-called "expanded criteria donor" (ECD) kidneys. Excellent outcomes have been achieved from ECD kidneys with appropriate donor and recipient profiling and selection. With increasing recovery efforts directed at older donors, the concept of age-matching is becoming more accepted as a method of optimizing utilization of organs in elderly donors and recipients. Utilization of pulsatile perfusion has further improved ECD outcomes and helped the decision-making process for the UNOS (United Network for Organ Sharing) offer. However, age-related immune dysfunction and associated co-morbidities make the elderly transplant recipients ever more susceptible to complications associated with immunosuppressive agents. Consequently, the elderly population is at a higher risk to develop infections and malignancy in the post-transplant period notwithstanding improved transplant outcomes. Appropriate immunosuppressive agents and dosages should be selected to minimize adverse events while reducing the risk of acute rejections and maximizing patient and renal allograft survival.

A prospective, randomized, double-blind, placebo-controlled multicenter trial comparing early (7 day) corticosteroid cessation versus long-term, low-dose corticosteroid therapy

OBJECTIVE

To compare outcomes with early corticosteroid withdrawal (CSWD) and chronic low dose corticosteroid therapy (CCS).

SUMMARY BACKGROUND DATA

Final, 5-year results from the first randomized, double-blind, placebo-controlled trial of early CSWD (at 7 days posttransplant) are presented.

METHODS

Adult recipients of deceased and living donor kidney transplants without delayed graft function were randomized to receive prednisone (5 mg/d after 6 months posttransplant) or CSWD. Blinding was maintained for 5 years. This clinical trial is registered at www.clinicaltrials.gov (NCT00650468).

RESULTS

Results in 386 patients CSWD (n = 191), CCS (n = 195) are presented (CSWD; CCS). No differences were observed at 5 years in the proportion of patients experiencing: primary end point (composite of death, graft loss, or moderate/severe acute rejection) (30/191 (15.7%); 28/195 (14.4%)), patient death (11/191(5.8%);13/195 (6.7%)), death-censored graft loss (11/191 (5.8%); 7/195(3.6%)), biopsy confirmed acute rejection (BCAR) (34/191 (17.8%); 21/195 (10.8%), P = 0.058), moderate/severe acute rejection (15/191 (7.9%); 12/195 (6.2%)). Kaplan Meier analyses of the primary end point and its components also showed no differences; but BCAR was higher with CSWD (P = 0.04). Increased BCAR episodes were primarily corticosteroid-sensitive Banff 1A rejections: the incidence of antibody-treated BCAR was similar between groups (11/191 (5.8%); 13/195 (6.7%)). No differences in renal function were observed at 5 years: mean serum creatinine (1.5 +/- 0.6; 1.5 +/- 0.7 mg/dL), or Cockroft Gault calculated creatinine clearance (58.6 +/- 19.7; 59.8 +/- 20.5 mL/min). CSWD was associated with improved serum triglycerides (evaluated by mean and median change from baseline) at all time points (except at 5 years measured by mean change). Weight change also demonstrated changes favoring CSWD (median change from baseline at 5 years: 5.1 vs. 7.7 kg, P = 0.05). New onset diabetes after transplant (NODAT) was similar with respect to proportions who required treatment (23/107 (21.5%)); 18/86 (20.9%); however, fewer CSWD patients required insulin for NODAT at 5 years (4/107 (3.7%)); 10/86 (11.6%), P = 0.049). Changes in HgA1c values (from baseline) were lower in CSWD patients at all time points except 4 years.

CONCLUSIONS

Early CSWD, compared with CCS, is associated with an increase in BCAR primarily because of mild, Banff 1A, steroid-sensitive rejection, yet provides similar long-term renal allograft survival and function. CSWD provides improvements in cardiovascular risk factors (triglycerides, NODAT requiring insulin, weight gain). Tacrolimus/MMF/antibody induction therapy allows early CSWD with results comparable to long-term low dose (5 mg/d) prednisone therapy.

Effect on kidney graft survival of reducing or discontinuing maintenance immunosuppression after the first year posttransplant

BACKGROUND

Data are scarce concerning the impact of maintenance immunosuppression dose reductions posttransplant.

METHODS

Graft survival according to dose reduction or discontinuation of calcineurin inhibitors or mycophenolate mofetil (MMF) after the first year posttransplant was evaluated in 25,045 patients undergoing kidney transplantation during 1996 to 2005. No patient in this analysis had experienced a rejection and all had good graft function before dose reduction.

RESULTS

Reduction of cyclosporine (CsA) dose to less than or equal to 150 mg/day, tacrolimus to less than or equal to 2 mg/day, or MMF to less than or equal to 1.0 g/day in patients on CsA or less than or equal to 0.5 g/day in patients on tacrolimus during the second year posttransplant was associated with a statistically significant reduction in graft survival (hazard ratios between 1.37 and 1.65). Withdrawal of CsA, tacrolimus, or MMF during year 2 was also associated with an increase in the risk of graft loss compared with continuing treatment (hazard ratio 1.52-1.73).

CONCLUSIONS

This observational analysis indicates that in kidney transplant patients with good graft function, withdrawing maintenance CsA, tacrolimus or MMF, or reducing the dose of these agents below certain thresholds after the first year posttransplant is associated with a significant risk of graft loss.

Impact of gastrointestinal-related side effects on mycophenolate mofetil dosing and potential therapeutic strategies

In renal transplant patients receiving mycophenolate mofetil (MMF), maintaining an adequate dosing regimen has been shown to maximize short- and long-term outcomes. Gastrointestinal (GI) adverse events associated with MMF are frequent, and lead to MMF dose reduction or withdrawal in 40-50% of cases. Among MMF-treated patients experiencing GI complications, one analysis has reported MMF discontinuation to be associated with almost a threefold increase in risk of graft loss, while a dose reduction > or = 50% carried over a twofold increase in risk. If GI symptoms improve and the pre-reduction MMF dose is resumed the increased risk of graft loss may be reversed, but continuing intolerance can make this difficult to achieve. Investigation of contributing factors is important and may alleviate symptoms. Conversion to enteric-coated mycophenolate sodium (EC-MPS) may be an effective option. Two open-label studies using patient-reported outcomes data have shown a significant and clinically relevant benefit in GI-related symptom burden after conversion from MMF to EC-MPS. In conclusion, monitoring of GI complications is essential following renal transplantation, and maintaining adequate mycophenolic acid exposure should be a priority when considering treatment options.

Minimization of calcineurin inhibitors to improve long-term outcomes in kidney transplantation

Long-term outcomes after kidney transplantation remain suboptimal, despite the great achievements observed in recent years with the use of modern immunosuppressive drugs. Currently, the calcineurin inhibitors (CNI) cyclosporine and tacrolimus remain the cornerstones of immunosuppressive regimens in many centers worldwide, regardless of their well described side-effects, including nephrotoxicity. In this article, we review recent CNI-minimization strategies in kidney transplantation, while emphasizing on the importance of long-term follow-up and patient monitoring. Finally, accumulating data indicate that low-dose CNI-based regimens would provide an interesting balance between efficacy and toxicity.

Minimization protocols in pancreas transplantation

Diagnosis of immunologic injury (acute and chronic) is much more difficult in pancreas transplants when compared with transplants of other organs. Currently, the immunosuppressive regimen for induction involves calcineurin inhibitors (CNI), antimetabolites and corticosteroids (Cs). This strong and nonspecific regimen does not take into consideration pancreas specificities (i.e. the need to avoid diabetogenic compounds). For obvious reasons, CNI might be calling for review, if permanently indicated in recipients of solitary pancreas with mild renal dysfunction. CNI as well as corticosteroids may induce hyperglycemia and contribute to differential diagnosis of a rejection process. However, in spite of the benefits accruing from withdrawal of above immunosuppressive agents, minimization or avoidance of these drugs could be dangerous and may end up with graft loss (i.e. antibody-mediated process). Long-term results of pancreas transplantation are now achieving comparable survival rates similar to the transplant of traditional organs such as kidney and liver. As a consequence, the physicians' objectives are to prolong the patient's quality of life and organ function as long as possible. Weaning strategies in regard to CNI and steroids are tested. Sirolimus, everolimus, CTLA-4 Ig, etc, are agents known to be either both nonnephrotoxic and nondiabetogenic or less so when compared with CNI. Their impact on pancreas transplantation is beginning to be evaluated. Large randomized trials in all pancreas categories, with long-term clinical and histologic results, are mandatory to establish new guidelines for immunosuppressive regimens for pancreas transplantation.

A drug transporter for all ages? ABCB1 and the developmental pharmacogenetics of cyclosporine

Evaluation of: Fanta S, Niemi M, Jönsson S et al.: Pharmacogenetics of cyclosporine in children suggests an age-dependent influence of ABCB1polymorphisms. Pharmacogenet. Genomics 18(2), 77-90 (2008). The clinical use of the immunosuppressive agent cyclosporine is complicated by its toxicity, narrow therapeutic window and highly variable pharmacokinetics between individuals. In adults, genetic polymorphisms in the genes encoding the cyclosporine-metabolizing enzymes CYP3A4 and CYP3A5, as well as the ABCB1 gene, which encodes the efflux-pump P-glycoprotein, seem to have a limited effect, if any, on cyclosporine pharmacokinetics. However, the authors have now reported for the first time an association between cyclosporine oral bioavailability and the ABCB1 c.1236C>T and c.2677G>T polymorphisms, as well as the related haplotype c.1199G-c.1236C-c.2677G-c.3435C, in children with end-stage renal disease older than 8 years of age. Carriers of the variant alleles had a cyclosporine oral bioavailability that was around 1.5-times higher compared with noncarriers. This association was not observed in children younger than 8 years of age. In addition, no relation between cyclosporine disposition and genetic variation in the CYP3A4, CYP3A5, ABCC2, SLCO1B1 and NR1I2 genes was observed. These data suggest that the effect of ABCB1 polymorphisms on cyclosporine pharmacokinetics is related to age, and thus developmental stage. Although further study is necessary to establish the predictive value of ABCB1 genotyping for individualization of cyclosporine therapy in children older than 8 years, an important step towards further personalized immunosuppressive drug therapy has been made.

Cytomegalovirus-specific T-cell responses and viral replication in kidney transplant recipients

Background

Cytomegalovirus (CMV) seronegative recipients (R-) of kidney transplants (KT) from seropositive donors (D+) are at higher risk for CMV replication and ganciclovir(GCV)-resistance than CMV R(+). We hypothesized that low CMV-specific T-cell responses are associated with increased risk of CMV replication in R(+)-patients with D(+) or D(-) donors.

Methods

We prospectively evaluated 73 consecutive KT-patients [48 R(+), 25 D(+)R(-)] undergoing routine testing for CMV replication as part of a preemptive strategy. We compared CMV-specific interferon-γ (IFN-γ) responses of CD4+CD3+ lymphocytes in peripheral blood mononuclear cells (PBMC) using three different antigen preparation (CMV-lysate, pp72- and pp65-overlapping peptide pools) using intracellular cytokine staining and flow cytometry.

Results

Median CD4+ and CD8+T-cell responses to CMV-lysate, pp72- and pp65-overlapping peptide pools were lower in D(+)R(-) than in R(+)patients or in non-immunosuppressed donors. Comparing subpopulations we found that CMV-lysate favored CD4+- over CD8+-responses, whereas the reverse was observed for pp72, while pp65-CD4+- and -CD8+-responses were similar. Concurrent CMV replication in R(+)-patients was associated with significantly lower T-cell responses (pp65 median CD4+ 0.00% vs. 0.03%, p = 0.001; CD8+ 0.01% vs. 0.03%; p = 0.033). Receiver operated curve analysis associated CMV-pp65 CD4+ responses of > 0.03% in R(+)-patients with absence of concurrent (p = 0.003) and future CMV replication in the following 8 weeks (p = 0.036). GCV-resistant CMV replication occurred in 3 R(+)-patients (6.3%) with pp65- CD4+ frequencies < 0.03% (p = 0.041).

Conclusion

The data suggest that pp65-specific CD4+ T-cells might be useful to identify R(+)-patients at increased risk of CMV replication. Provided further corroborating evidence, CMV-pp65 CD4+ responses above 0.03% in PBMCs of KT patients under stable immunosuppression are associated with lower risk of concurrent and future CMV replication during the following 8 weeks.

Long-term efficacy and safety of a calcineurin inhibitor-free regimen in live-donor renal transplant recipients

Calcineurin inhibitor (CNI) nephrotoxicity is a major concern after renal transplantation. To investigate the safety and efficacy of a CNI-free immunosuppressive regimen, 132 live-donor renal transplant recipients were included in a prospective, randomized controlled trial. All patients received induction therapy with basiliximab and steroids. The patients were randomized to a maintenance immunosuppression regimen that included steroids, sirolimus, and either low-dose tacrolimus or mycophenolate mofetil (MMF). Over a mean follow-up period of approximately 5 yr, patient and graft survival did not significantly differ between the two maintenance regimens. Patient survival was 93.8% and 98.5% in the tacrolimus/sirolimus and MMF/sirolimus groups, respectively, and graft survival was 83% and 88%, respectively. However, the MMF/sirolimus group had significantly better renal function, calculated by Cockcroft-Gault, from the second year post-transplant until the last follow-up. In addition, this group was less likely to require a change in their primary immunosuppression regimen than the tacrolimus/sirolimus group (20.8% versus 53.8%, P = 0.001). The safety profile was similar between groups. In summary, after long-term follow-up, a CNI-free maintenance regimen consisting of sirolimus, MMF, and steroids was both safe and efficacious among low to moderate immunologic risk renal transplant recipients.

Kidney transplant histology after one year of continuous therapy with sirolimus compared with tacrolimus

Analysis of 1-year surveillance biopsies was carried out for kidney transplant recipients participating in a randomized trial comparing tacrolimus- and sirolimus-based immunosuppression. The analysis was restricted to recipients remaining on assigned regimen throughout the first posttransplant year. Biopsies from 57 of 84 (68%) tacrolimus-randomized recipients were compared with 38 of 81 (47%) of sirolimus-randomized recipients, the discrepancy being explained by a higher rate of sirolimus discontinuation for non-graft-related complications. Included recipients from the two groups did not differ for baseline characteristics or 1-year iothalamate clearance. Histologic analysis indicated no differences between the groups for glomerular, arterial/arteriolar, or acute interstitial abnormalities. There were, however, significantly higher mean scores in the tacrolimus group for interstitial fibrosis and tubular atrophy with a trend toward higher estimated percent interstitial fibrosis. The results indicate that sirolimus may be associated with reduced early graft fibrosis compared with tacrolimus. This potential benefit is offset by lower success rate in maintaining the regimen and was not accompanied by superior glomerular filtration rate at 1 year.

Insulin-like growth factor I improves aspects of mycophenolate mofetil-impaired anastomotic healing in an experimental model

Background

Patients taking immunosuppressants after transplantation may require intestinal surgery. Mycophenolate mofetil (MMF) has been found to impair the healing of colonic anastomoses in rats. This study examined whether insulin-like growth factor (IGF) I prevents MMF impairment of anastomotic healing.

Methods

Sixty-three rats were divided into three groups (MMF, MMF/IGF and control). Animals underwent a sigmoid colon anastomosis with a 6/0 suture, and were killed on days 2, 4 and 6 after surgery. Investigations included bursting pressure measurement, morphometric analysis, and assessment of mucosal proliferation by 5-bromo-2′-deoxyuridine and Ki67 immunohistochemistry of the anastomoses.

Results

The leak rate was three of 21, one of 20 and two of 20 in the MMF, MMF/IGF-I and control groups respectively. Anastomotic bursting pressures were significantly lower in the MMF group than in the control group on days 2 and 4, but there was no significant difference by day 6. Values in the MMF/IGF-I and control groups were similar. Colonic crypt depth was significantly reduced in MMF-treated animals on days 2 and 4, but this impairment was attenuated by IGF-I on day 4. Similarly, IGF-I reduced the negative impact of MMF on mucosal proliferation on days 2 and 6.

Conclusion

Exogenous IGF-I improves some aspects of MMF-impaired anastomotic healing.

BK virus nephritis after renal transplantation

BK virus nephritis is an increasing problem and is posing a threat to improving renal transplant graft survival. The pathogenesis of this condition remains to be investigated. Higher prevalence of BK virus infection in recent years has been correlated with declining acute rejection rates and the use of potent immunosuppressive agents. Patients with this infection usually have asymptomatic viremia and/or nephritis with or without worsening of renal function. The diagnosis of this disease is based on detecting the virus or its effects in urine, blood, and renal tissue. In the past, approximately 30 to 60% of patients with BK virus nephritis developed graft failure. In recent years, the combination of early detection, prompt diagnosis, and therapies including preventive measures have resulted in better outcomes.

Polyomavirus BK with rearranged noncoding control region emerge in vivo in renal transplant patients and increase viral replication and cytopathology

Immunosuppression is required for BK viremia and polyomavirus BK–associated nephropathy (PVAN) in kidney transplants (KTs), but the role of viral determinants is unclear. We examined BKV noncoding control regions (NCCR), which coordinate viral gene expression and replication. In 286 day–matched plasma and urine samples from 129 KT patients with BKV viremia, including 70 with PVAN, the majority of viruses contained archetypal (ww-) NCCRs. However, rearranged (rr-) NCCRs were more frequent in plasma than in urine samples (22 vs. 4%; P < 0.001), and were associated with 20-fold higher plasma BKV loads (2.0 × 10⁴/ml vs. 4.4 × 10⁵/ml; P < 0.001). Emergence of rr-NCCR in plasma correlated with duration and peak BKV load (R² = 0.64; P < 0.001). This was confirmed in a prospective cohort of 733 plasma samples from 227 patients. For 39 PVAN patients with available biopsies, rr-NCCRs were associated with more extensive viral replication and inflammation. Cloning of 10 rr-NCCRs revealed diverse duplications or deletions in different NCCR subregions, but all were sufficient to increase early gene expression, replication capacity, and cytopathology of recombinant BKV in vitro. Thus, rr-NCCR BKV emergence in plasma is linked to increased replication capacity and disease in KTs.

Management of cardiovascular disease in renal transplant recipients

Cardiovascular disease is a major cause of graft loss and the leading cause of death in renal transplant recipients. Although there are robust data on the frequency of risk factors and their contributions to cardiovascular disease in this population, few trials have demonstrated the benefit of modifying these risk factors to reduce cardiovascular events. Nevertheless, it is widely accepted that the clinical acumen filtered through the best available studies in the general population be used to treat individual renal transplant recipients given their high cardiovascular mortality. Transplant task forces and the Kidney Disease Outcomes Quality Initiative have created guidelines for this purpose. This review examines the data available for prevention and treatment of major risk factors contributing to cardiovascular disease in renal transplant recipients. The contribution of immunosuppressive agents to each risk factor and the evidence to support lifestyle modification as well as drug therapy are examined. Reducing cardiovascular risk factors requires an integrative approach that is best accomplished by a team of health care professionals. It creates a significant challenge but one that must be met if allograft survival is to improve.

Minimizing immunosuppression, an alternative approach to reducing side effects: objectives and interim result

Exceptionally low acute rejection rates and excellent graft survival can be achieved with cyclosporine and tacrolimus (CNI)-based immunosuppressive protocols that incorporate antiproliferative immunosuppressants and corticosteroids. However, despite short-term success, long-term attrition of graft function and side effects of immunosuppressive agents continue to be significant problems, leaving clinicians looking for possible interventions. CNI nephrotoxicity is but one of numerous factors that may contribute to long-term damage in transplant kidneys. Metabolic, cosmetic, and neuropsychiatric complications of steroids affect quality of life after transplantation. Newer immunosuppressive agents such as mycophenolate mofetil and sirolimus (Rapa) have raised the possibility of withdrawing or avoiding CNIs or steroids altogether. In this report we review studies that address either CNI or steroid minimization strategies and discuss their risks versus benefits. Given the accumulated experience to date, in our opinion the use of CNIs and steroids as part of immunosuppressive regimens remains the proven standard of care for renal transplant patients. The long-term safety and efficacy of CNI and steroid minimization strategies needs to be further validated in controlled clinical trials with adequate long-term follow-up.

Campath-1H induction therapy in African American and Hispanic first renal transplant recipients: 3-year actuarial follow-up

BACKGROUND

In a retrospective study of the first 75 primary renal transplant patients given alemtuzumab induction at our center, 20 were African American (27%), 32 were Hispanic (43%), and 23 were non-African American, non-Hispanic (31%).

METHODS

Alemtuzumab was given intraoperatively and 4 days later (0.3 mg/kg), with planned low-dose maintenance mycophenolate mofetil (500 mg twice daily) and tacrolimus (targeted trough levels of 5 to 7 ng/ml) and no corticosteroid therapy after the first week. Median follow-up among ongoing survivors with a functioning graft was 45 months.

RESULTS

Three-year actuarial patient and graft survival rates were 95% and 85% in African Americans, 89% and 78% in Hispanics, and 96% and 96% in non-African Americans, non-Hispanics, respectively (not significant). Bioavailability of tacrolimus was significantly lower among African Americans in comparison with the other patient subgroups (P

CONCLUSIONS

This immunosuppressive protocol appears reasonably safe for 3 years after renal transplantation but suggests higher incidences of biopsy-proven acute rejection, chronic allograft dysfunction, and borderline poorer renal function among African Americans in comparison with the other patient subgroups.

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MESH Headings

• Adult
• Alemtuzumab
• Antibodies, Monoclonal/therapeutic use
• Antibodies, Monoclonal, Humanized
• Antibodies, Neoplasm/therapeutic use
• Antineoplastic Agents/therapeutic use
• Black People
• Cause of Death
• Female
• Follow-Up Studies
• Graft Rejection/drug therapy
• Graft Rejection/epidemiology
• Graft Survival
• Hispanic or Latino
• Histocompatibility Testing
• Humans
• Immunosuppressive Agents/therapeutic use
• Kidney Transplantation/adverse effects
• Kidney Transplantation/immunology
• Kidney Transplantation/mortality
• Male
• Middle Aged
• Organ Preservation
• Postoperative Complications/epidemiology
• Retrospective Studies
• Survival Analysis
• Tissue Donors/statistics & numerical data
• Black or African American

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Affiliation(s)

Gaetano Ciancio Lillian Jean Kaplan Renal Transplant Center, Division of Transplantation, Department of Surgery, University of Miami Miller School of Medicine, Miami, FL 33101, USA.
George W Burke
Jeffrey J Gaynor
Junichiro Sageshima
Eva Herrada
Lissett Tueros
David Roth
Warren Kupin
Anne Rosen
Violet Esquenazi
Joshua Miller

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Influence of immunosuppressive regimens on short-term morbidity and mortality in heart transplantation

BACKGROUND

The goal of immunosuppressive therapy in heart transplantation is to maximize safety and efficacy while minimizing morbidity and mortality. We now have numerous drug combinations, but few have been compared with each other.

AIM

To compare various immunosuppressive regimens assessing morbidity and mortality at one yr.

METHODS

A total of 351 patients transplanted between 1989 and 2005 were included and grouped by immunosuppressive regimen into group 1 (n = 52): Muronomab (OKT3) 10 d, cyclosporine (CSA), azathioprine (AZA), steroids; group 2 (n = 193): OKT3 seven d, CSA, AZA, steroids; group 3 (n = 22): OKT3 seven d, CSA, mycophenolate mofetil (MMF), steroids; and group 4 (n = 84): interleukin-2 antagonists (IL-2), CSA, MMF, steroids.

RESULTS

The incidence of acute graft failure and treated rejection was similar between groups (17% and 78% respectively). We found a statistically significant difference in the incidence of infections (p < 0.001), renal dysfunction (p = 0.011) and in diabetes mellitus (p = 0.023). There were no differences in survival at 30 d (97%), but differences were found at one yr (p = 0.011). The multivariate analysis showed a strong association between mortality and infection (p = 0.001) and between survival and the group 4 regimen (p < 0.001).

CONCLUSION

There are differences in survival at one yr of heart transplant patients depending on the immunosuppressive regimen used. The best combination was induction with IL-2 antagonists, followed by CSA, MMF and steroids.

Early, abrupt conversion of de novo renal transplant patients from cyclosporine to everolimus: results of a pilot study

In a single-center study, 20 kidney transplant patients without prior rejection were abruptly converted from cyclosporine to everolimus at seven wk post-transplant. All patients received basiliximab induction with maintenance enteric-coated mycophenolate sodium and corticosteroids. Biopsy-proven acute rejection had occurred in three of 20 patients (15.0%) by the end of week seven post-conversion. All episodes were mild and reversible, with subsequent recovery of renal function. Calculated glomerular filtration rate (GFR) improved significantly (51 +/- 11 mL/min at time of conversion, 58 +/- 12 mL/min at week seven post-conversion, 57 +/- 17 mL/min at month six post-conversion; p = 0.001). No patient developed proteinuria in the nephrotic range. Twenty-two adverse events were reported in 10 patients, three of which had a suspected relationship to everolimus. Mean leukocyte and platelet count decreased significantly, and triglyceride level increased. This study suggests that kidney transplant patients without prior rejection can be converted abruptly from cyclosporine to everolimus at seven wk post-transplant, resulting in significantly improved renal function with no apparent increase, in risk of rejection and good tolerability.

Impact of tacrolimus and mycophenolate mofetil combination on cardiovascular risk profile after kidney transplantation

Cardiovascular risk factors after kidney transplantation are enhanced as a result of the chronic use of immunosuppressants. Tacrolimus with mycophenolate mofetil has become the most commonly used combination after kidney transplantation. Cardiovascular risk factors that are related to the use of this combined therapy have been analyzed in various clinical trials in comparison with other immunosuppressive therapies. This review summarizes the main results of these studies regarding arterial hypertension, lipid profile, posttransplantation diabetes, renal function, and even acute rejection rate. The aim is to characterize the cardiovascular risk profile of tacrolimus and mycophenolate mofetil association when compared with older and newer immunosuppressive associations.

Renal function in patients with cadaveric kidney transplants treated with tacrolimus or cyclosporine

INTRODUCTION

Renal function predicts graft survival in kidney transplant patients. This study compared the 2-year evolution of renal function in patients treated with cyclosporine or tacrolimus in combination with mycophenolate mofetil (MMF) and prednisone.

METHODS

We studied 1558 cadaveric renal transplant recipients from 14 Spanish hospitals between January 2000 and December 2002. Of these, 1168 were treated with tacrolimus and 390 with cyclosporine. The primary efficacy endpoint was long-term renal function. Renal function was measured by serum creatinine and glomerular filtration rate (GFR) by creatinine clearance calculated from the Cockcroft-Gault formula. This report summarizes the 2-year results.

RESULTS

At 24 months the tacrolimus group showed significantly better serum creatinine (1.5 +/- 0.7 vs 1.8 +/- 0.8 mg/dL, P < .001) and GFR (60.5 +/- 20.9 mL/min vs 47.9 +/- 10.0, P < .001) than the cyclosporine group. Additionally, recipients with ideal graft donors (23.5 +/- 2.8 vs 24.0 +/- 2.9 years) had a better serum creatinine at 2 years (1.23 +/- 0.2 vs 1.5 +/- 0.4 mg/dL, P < .05). Multivariate analysis showed that tacrolimus was an independent factor associated with better renal function: odds ratio 1.6, 95% confidence interval (1.2 to 2.2), P < .001.

CONCLUSIONS

Patients with a renal transplant treated with tacrolimus in combination with MMF and prednisone displayed better renal function at 2 years than those who received cyclosporine.

T-cell function monitoring in stable renal transplant patients treated with sirolimus monotherapy

BACKGROUND

Sirolimus is an agent with lymphocyte-specific features similar to those of calcineurin inhibitors but with a different mechanism of action and safety profile. To optimize the use of sirolimus-based immunosuppression, further investigation of appropriate pharmacokinetic (sirolimus exposure) and pharmacodynamic (sirolimus T-cell immunomodulator effect) monitoring is required to determine personalized target concentrations.

AIM

The main objective of the study was to evaluate the feasibility and reproducibility of combined pharmacokinetic and pharmacodynamic monitoring and to apply biomarkers of immunosuppression in stable kidney transplant recipients receiving sirolimus monotherapy.

METHODS

Fourteen renal transplant patients treated with sirolimus monotherapy (median 2 years) were included in this study. Pharmacokinetic and pharmacodynamic parameters were evaluated in each patient three times: at inclusion in the study (day 1), then again at 3 and 6 months.

RESULTS

The median sirolimus concentration was 11.5 ng/mL. CD4+ T-cell adenosine triphosphate (ATP) concentrations (150 ng/mL) and interleukin (IL)-10 production (50.9 ng/mL) were significantly lower in treated patients than in healthy controls (n = 95) [301 ng/mL; 278 ng/mL, respectively]. Median inhibition of T-cell proliferation was 60% (31-96%) in treated patients. Interferon-gamma and transforming growth factor-beta production was found to be similar to those in the healthy controls. Our results suggest an association between low ATP and IL-10 concentrations and the presence of infection.

CONCLUSIONS

The sequential measurement of these biomarkers in stable renal transplant recipients treated with monotherapy could be useful to evaluate the biological effect of sirolimus in each patient and to establish personalized therapy taking into account the individual response to the drug.

Immunosuppression of the elderly kidney transplant recipient

The growing number of elderly patients with end-stage kidney disease awaiting transplantation has resulted in a corresponding rise in the number of elderly transplant recipients. In this paper, we review existing literature on age-related changes, transplant outcomes, and complications in the elderly in an attempt to propose a tailored approach to immunosuppression management in this group of patients. Despite the fact that the benefit of transplantation in the elderly is well established, clinical trials evaluating the safety and efficacy of immunosuppression regimens are lacking. Until such data exists, immunosuppression of the elderly transplant recipient should be based on the traditional principles which guide all transplant protocols and consideration of factors that are unique to the elderly. There are limited data regarding age-related changes in immune function and metabolism of immunosuppression agents in this population. Results of registry data analyses suggest that the risk of acute rejection decreases with age; however, the impact of acute rejection on long-term allograft function is greater in this population. There is also an increased risk of infection and adverse events posttransplantation among these patients. Elderly patients are more likely to receive organs from extended criteria donors and the impact of donor factors on transplant outcomes must therefore be considered. Taking these factors into consideration, we propose an approach to immunosuppression in the elderly based on individual risk stratification of treatment failure and the potential for adverse events.

Immunosuppressive strategies to improve outcomes of kidney transplantation

The introduction of several immunosuppressive agents over the past decade has reduced the rate of acute rejection significantly and has improved short-term renal allograft survival. However, their impact on long-term outcomes remains unclear. Current immunosuppressive strategies are focused on improving long-term graft and patient survival along with maintaining allograft function. The approval of the new immunosuppressive agents: rabbit antithymocyte globulin, basiliximab, daclizumab, tacrolimus, mycophenolate, and sirolimus, also has facilitated the development of steroid- and calcineurin inhibitor-sparing regimens in kidney transplantation. We discuss the impact of various immunosuppressive regimens on the outcome measures of kidney transplantation: acute rejection episodes, allograft survival, and renal function.

Hepatitis C virus infection and risk of posttransplantation lymphoproliferative disorder among solid organ transplant recipients

Posttransplantation lymphoproliferative disorder (PTLD) is a serious complication of solid organ transplantation. Hepatitis C virus (HCV) infection has been linked to increased risk of lymphoma among immunocompetent individuals. We therefore investigated the association between HCV infection and PTLD in a retrospective cohort study of all individuals in the United States who received their first solid organ transplant from 1994 to 2005 (N = 210 763) using Scientific Registry of Transplant Recipients data. During follow-up, 1630 patients with PTLD were diagnosed. HCV prevalence at transplantation was 11.3%. HCV infection did not increase PTLD risk in the total cohort (Cox regression model, hazard ratio [HR] = 0.84; 95% confidence interval [CI] 0.68-1.05), even after adjustment for type of organ transplanted, indication for transplantation, degree of HLA mismatch, donor type, or use of immunosuppression medications. Additional analyses also revealed no association by PTLD subtype (defined by site, pathology, cell type, and tumor Epstein-Barr virus [EBV] status). HCV infection did increase PTLD risk among the 2.8% of patients (N = 5959) who were not reported to have received immunosuppression maintenance medications prior to hospital discharge (HR = 3.09; 95% CI, 1.14-8.42; P interaction = .007). Our findings suggest that HCV is not a major risk factor for PTLD, which is consistent with the model in which an intact immune system is necessary for development of HCV-related lymphoproliferation.

Alemtuzumab induction and recurrence of glomerular disease after kidney transplantation

BACKGROUND

An increase in the incidence of autoimmune diseases has been described in patients receiving alemtuzumab.

METHODS

To determine whether induction with alemtuzumab increases recurrence of glomerular disease, we performed a retrospective study in 443 patients with biopsy-proven glomerular diseases undergoing kidney transplantation. Patients receiving alemtuzumab (n=161) were compared with those receiving interleukin (IL)-2-receptor antagonists (n=217) or antithymocyte globulin (n=64).

RESULTS

Biopsy-proven glomerular disease recurrence was similar in patients induced with alemtuzumab or IL-2 receptor antagonists. Patients receiving antithymocyte antibody had a lower recurrence rate than patients treated with other induction agents, with borderline significance (hazard ratio [HR] 0.13, 95% confidence interval [95% CI] 0.02-0.98, P=0.047). Patients with systemic lupus treated with alemtuzumab had a similar re-emergence of autoreactive antibodies to patients treated with other agents. Recurrent disease increased the risk of allograft failure (HR 2.36, 95% CI 1.28-4.32, P=0.0056). The development of acute rejection and the use of deceased (vs. living) donor kidneys were also significant factors influencing graft survival. A greater risk of mortality was detected in those patients with recurrent glomerular disease (HR 3.76, 95% CI 1.37-10.35, P=0.01), whereas increased age at transplantation (HR 1.05) and the use of deceased (vs. living) donor kidneys (HR 3.20) also increased mortality. No specific induction agent significantly affected graft loss or mortality when using adjusted or unadjusted hazard ratios.

CONCLUSIONS

In this retrospective analysis, induction with alemtuzumab did not increase the rate of re-emergence of autoantibodies or biopsy-proven recurrence of glomerular disease. A slight reduction in the incidence of recurrence was observed in patients treated with thymoglobulin, yet this observation can only be validated in a prospective randomized trial.

Calcineurin inhibitor-free immunosuppression in kidney transplantation

The introduction of calcineurin inhibitors (CNI) revolutionized kidney transplantation (KTx). Exceptionally low acute rejection rates and excellent graft survival could be achieved with CNI-based (cyclosporine and tacrolimus) immunosuppressive protocols. However, despite short-term success, long-term graft attrition continues to be a significant problem, thus leaving clinicians looking for possible interventions. CNI nephrotoxicity is but one of numerous factors that may be contributing to long-term damage in transplant kidneys. Therefore, newer immunosuppressive agents such as mycophenolate mofetil and sirolimus (Rapa) have raised the possibility of withdrawing or avoiding CNIs altogether. Protocols exploring these options have gained greater attention over the last few years. Herein, we review studies addressing either CNI withdrawal or CNI avoidance strategies as well as discuss the risks versus benefits of these protocols. Given the accumulated experience to date, in our opinion, the use of CNIs as a part of immunosuppressive regimens remains the proven standard of care for renal transplant patients. The long-term safety and efficacy of CNI withdrawal and avoidance strategies need to be further validated in controlled clinical trials.

Plasma concentrations of mycophenolic acid acyl glucuronide are not associated with diarrhea in renal transplant recipients

The aim of this study was to determine whether plasma concentrations of the acyl (AcMPAG) and phenolic (MPAG) glucuronide metabolites of mycophenolic acid (MPA) were related to diarrhoea in renal transplant patients on mycophenolate mofetil (MMF) with cyclosporine (CsA) or tacrolimus (TCL). Blood samples (0, 30, 120 min) were taken at days 3, 10, week 4, months 3, 6 and 12 for determination of MPA, MPAG and AcMPAG. MPA-AUC was estimated using validated algorithms. Two hour AUCs were calculated for MPAG and AcMPAG. Immunosuppressive therapy consisted of CsA/MMF (n= 110) and of TCL/MMF (n= 180). In 70/290 (24%) patients 86 episodes of diarrhoea were recorded during 12 months. Significantly more patients on TCL (31.1%) suffered from diarrhea compared to CsA (12.7%). MMF dose, MPA-AUC and the 2 h AUCs of MPAG and AcMPAG did not differ between patients with and without diarrhoea. Plasma AcMPAG and MPAG concentrations were substantially higher in patients on CsA compared with TCL, while MPA-AUC was lower in the former group. These data support the concept that CsA inhibits the biliary excretion of MPAG and AcMPAG, thereby potentially reducing the risk of intestinal injury through enterohepatic recycling of MPA and its metabolites.

Liver and intestine transplantation in the United States, 1996-2005

The number of liver transplants performed yearly has slowly and steadily increased over the last 10 years, reaching 6441 procedures in 2005. The number of living donor liver transplants performed rose steadily from 1996 to 2001, when it peaked at 519; since 2003 there have been approximately 320 such procedures performed each year. The continual increase in the size of the waiting list for a liver transplant, which peaked in 2001 at 14 897 patients, was interrupted in 2002 by the implementation of the allocation system based on the model for end-stage liver disease and pediatric end-stage liver disease (MELD/PELD). Activity in all areas of intestinal transplantation continues to increase. One-year patient and graft survival following intestine-alone transplantation now seem to be superior to outcomes following liver-intestine transplantation. Other topics covered here include the recent 'Share 15' component of the MELD allocation system; liver transplantation following donation after cardiac death; simultaneous liver-kidney transplantation and waiting list and post-transplant outcomes for both liver and intestine transplantation, broken out by a variety of clinical and demographic factors.

Prophylactic treatment of antibody-mediated rejection with high-dose mizoribine and pharmacokinetic study

Although mizoribine (MZ), which inhibits inosine monophosphate dehydrogenase in the same way as mycophenolate mofetil, recently proved more effective when higher doses were administered than previously approved, neither the optimal dosage nor blood concentration has yet been clarified. We aimed at investigating the effect of high-doses of MZ on prevention of anti-donor antibody (Ab) production and acute Ab-mediated rejection (AMR) on the basis of the pharmacokinetic profile in a pig kidney transplantation model. Group 1 (n = 5) received cyclosporin microemulsion (6 mg/kg) and prednisolone (0.1 mg/kg). Groups 2, 3 and 4 (each n = 5) were treated, respectively, with 30, 10 and 3 mg/kg of MZ in addition to cyclosporin and prednisolone. The incidences of AMR in groups 1, 2, 3 and 4 were 5/5, 1/5, 3/5 and 5/5, respectively. Anti-donor IgG/IgM Ab levels (relative to pretransplantation levels) on day 14 in groups 1, 2, 3 and 4 were 10.3/9.3, 1.8/1.0, 2.3/1.8 and 6.5/3.5, respectively. While only 2 (28.6%) of seven pigs with Cmax > 3 microg/ml during the first 2 weeks had AMR, 7 (87.5%) of eight pigs with Cmax < 3 microg/ml elicited anti-donor Abs and experienced AMR (P = 0.0406). Effective Cmax seemed to be over 3 microg/ml at minimum. Higher doses of MZ efficiently prevented AMR. However, therapeutic drug monitoring is essential before clinical application.

Mycophenolate mofetil/sirolimus compared to other common immunosuppressive regimens in kidney transplantation

We evaluated outcomes with the sirolimus (SRL) and mycophenolate mofetil (MMF) combination regimen (SRL/MMF) in solitary kidney transplant recipients transplanted between 2000 and 2005 reported to the Scientific Registry of Renal Transplant Recipients. Three-and-a-half percent received SRL/MMF (n = 2040). Six-month acute rejection rates were higher with SRL/MMF (SRL/MMF: 16.0% vs. other regimens: 11.2%, p < 0.001). Overall graft survival was significantly lower on SRL/MMF. SRL/MMF was associated with twice the hazard for graft loss (AHR = 2.0, 95% C.I., 1.8, 2.2) relative to TAC/MMF, also consistent in both living donor transplants (AHR = 2.4, 95% C.I., 1.9, 2.9) and expanded criteria donor transplants (AHR = 2.1, 95% C.I., 1.7-2.5). Among deceased donor transplants, DGF rates were higher in the SRL/MMF cohort (47% vs. 27%, p < 0.001). However, adjusted graft survival was also significantly inferior with SRL/MMF in DGF-free patients (AHR = 1.9, 95% C.I., 1.6-2.3). In analyses restricted to patients who remained on the discharge regimen at 6 months posttransplant, conditional graft survival in deceased donor transplants was significantly lower with SRL/MMF compared to patients on TAC/MMF or CsA/MMF regimens at 5 years posttransplant (64%, 78%, 78%, respectively, p = 0.001) and across all patient subgroups. In conclusion, SRL/MMF is associated with inferior renal transplant outcomes compared with other commonly used regimens.

Clobetasol ameliorates aphthous ulceration in renal transplant patients on sirolimus

Aphthous ulceration is a common side effect of sirolimus. These lesions of the oral mucous membranes are often painful and debilitating, leading to either dose reduction or discontinuation of sirolimus in a significant number of patients. We report that the direct application of clobetasol, a high potency topical steroid, led to prompt resolution of the aphthous ulcers that developed in our renal transplant patients on sirolimus-based immunosuppression.

Report of the First World Transplant Congress

During the past 20 yr, new immunosuppressant medications that reduced the rate of acute rejection became available for transplantation. Long-term survival of transplanted organs, however, did not improve to the extent predicted. Chronic immunosuppression is associated with cardiovascular, metabolic, and renal toxicities that negatively affect patient and graft survival. Therefore, there is a pressing need for new approaches to immunosuppression that might better prevent acute rejection with a safety profile that is superior to current regimens. Moreover, the performance of currently available agents should be largely ameliorated by optimizing drug combinations and dosages. The latter goal can be achieved only through the development of specific immune markers of over- and underimmunosuppression to help tailor the immunosuppressive regimen for individual patients and even to allow safe withdrawal of immunosuppression in selected patients. Recent research has resulted in the discovery of new pathways of alloimmune reactivity, thereby offering novel immunologic targets for more specific and minimally toxic antirejection therapies. Finally, recent achievements pushed transplant medicine forward toward its ultimate goal of achieving a condition of tolerance for allogeneic antigens that prevents acute rejection without maintenance immunosuppression. All of these topics were addressed in the more than 3000 abstracts that were presented at the World Transplant Congress, held in Boston July 22 through 27, 2006.