Successful tapering of immunosuppression to low-dose monotherapy steroids after living-related human leukocyte antigen-identical renal transplantation

Recommendations for living donor kidney transplantation

This Guide for Living Donor Kidney Transplantation (LDKT) has been prepared with the sponsorship of the Spanish Society of Nephrology (SEN), the Spanish Transplant Society (SET), and the Spanish National Transplant Organization (ONT). It updates evidence to offer the best chronic renal failure treatment when a potential living donor is available. The core aim of this Guide is to supply clinicians who evaluate living donors and transplant recipients with the best decision-making tools, to optimise their outcomes. Moreover, the role of living donors in the current KT context should recover the level of importance it had until recently. To this end the new forms of incompatible HLA and/or ABO donation, as well as the paired donation which is possible in several hospitals with experience in LDKT, offer additional ways to treat renal patients with an incompatible donor. Good results in terms of patient and graft survival have expanded the range of circumstances under which living renal donors are accepted. Older donors are now accepted, as are others with factors that affect the decision, such as a borderline clinical history or alterations, which when evaluated may lead to an additional number of transplantations. This Guide does not forget that LDKT may lead to risk for the donor. Pre-donation evaluation has to centre on the problems which may arise over the short or long-term, and these have to be described to the potential donor so that they are able take them into account. Experience over recent years has led to progress in risk analysis, to protect donors' health. This aspect always has to be taken into account by LDKT programmes when evaluating potential donors. Finally, this Guide has been designed to aid decision-making, with recommendations and suggestions when uncertainties arise in pre-donation studies. Its overarching aim is to ensure that informed consent is based on high quality studies and information supplied to donors and recipients, offering the strongest possible guarantees.

Transcriptomic studies in tolerance: Lessons learned and the path forward

Immunosuppression after solid organ transplantation is a delicate balance of the immune response and is a complex phenomenon with many factors involved. Despite advances in the care of patients receiving organ transplants the adverse effects associated with immunosuppressive agents and the risks of long-term immunosuppression present a series of challenges and the need to weigh the risks and benefits of either over or under-immunosuppression. Ideally, if all transplant recipients could develop donor-specific immunological tolerance, it could drastically improve long-term graft survival without the need for immunosuppressive agents. In the absence of this ideal situation, the next best approach would be to develop tools to determine the adequacy of immunosuppression in each patient, in a manner that would individualize or personalize therapy. Despite current genomics-based studies of tolerance biomarkers in transplantation there are currently, no clinically validated tools to safely increase or decrease the level of IS that is beneficial to the patient. However, the successful identification of biomarkers and/or mechanisms of tolerance that have implications on long-term graft survival and outcomes depend on proper integration of study design, experimental protocols, and data-driven hypotheses. The objective of this article is to first, discuss the progress made on genomic biomarkers of immunological tolerance and the future avenues for the development of such biomarkers specifically in kidney transplantation. Secondly, we provide a set of guiding principles and identify the pitfalls, advantages, and drawbacks of studies that generate genomic data aimed at understanding transplant tolerance that is applicable to all solid transplants.

Nonchimeric HLA-Identical Renal Transplant Tolerance: Regulatory Immunophenotypic/Genomic Biomarkers

We previously described early results of a nonchimeric operational tolerance protocol in human leukocyte antigen (HLA)-identical living donor renal transplants and now update these results. Recipients given alemtuzumab, tacrolimus/MPA with early sirolimus conversion were multiply infused with donor hematopoietic CD34(+) stem cells. Immunosuppression was withdrawn by 24 months. Twelve months later, operational tolerance was confirmed by rejection-free transplant biopsies. Five of the first eight enrollees were initially tolerant 1 year off immunosuppression. Biopsies of three others after total withdrawal showed Banff 1A acute cellular rejection without renal dysfunction. With longer follow-up including 5-year posttransplant biopsies, four of the five tolerant recipients remain without rejection while one developed Banff 1A without renal dysfunction. We now add seven new subjects (two operationally tolerant), and demonstrate time-dependent increases of circulating CD4(+) CD25(+++) CD127(-) FOXP3(+) Tregs versus losses of Tregs in nontolerant subjects (p < 0.001). Gene expression signatures, developed using global RNA expression profiling of sequential whole blood and protocol biopsy samples, were highly associative with operational tolerance as early as 1 year posttransplant. The blood signature was validated by an external Immune Tolerance Network data set. Our approach to nonchimeric operational HLA-identical tolerance reveals association with Treg immunophenotypes and serial gene expression profiles.

Calcineurin inhibitors in HLA-identical living related donor kidney transplantation

BACKGROUND

Given the nephrotoxicity of calcineurin inhibitors (CNIs), we asked whether their addition improved living related donor (LRD) human leukocyte antigen (HLA) identical kidney transplant recipient outcomes.

METHODS

We performed a comprehensive literature review and a single-center study comparing patient survival (PS) and graft survival (GS) of LRD HLA-identical kidney transplants for three different immunosuppression eras: Era 1 (up to 1984): anti-lymphocyte globulin (ALG) induction and maintenance immunosuppression with prednisone and azathioprine (AZA) (n = 114); Era 2a (1984-99): CNI added; evolution from ALG to thymoglobulin; AZA to mycophenolate (n = 262). Era 2b (1999-2011): rapid discontinuation of prednisone (thymoglobulin induction, CNI and mycophenolate) in recipients having first or second transplant and not previously on prednisone (n = 77).

RESULTS

Demographics differed by era: recipient (P < 0.0001) and donor age (P < 0.0001) increased and the proportion of Caucasian donors (P = 0.02) and recipients (P = 0.003) decreased with each advancing era. There was no significant difference in PS (P = 0.6); cause of death (P = 0.5); death-censored GS (P = 0.8) or graft loss from acute rejection by era. Graft loss from chronic allograft nephropathy (P = 0.02) and hypertension (P = 0.005) were greater in the CNI eras. There were no significant differences in the 1/creatinine slopes between eras for the first (P = 0.6), second (P = 0.9) or >2 years post-transplant (P = 0.4). Literature review revealed no clear benefits for CNI in these human leukocyte antigen (HLA) identical LRD graft recipients.

CONCLUSIONS

This study confirmed that there are no benefits of CNIs for HLA-identical LRD recipients. Moreover, we did find evidence of potential harm. Thus, monotherapy or early discontinuation of CNI should be given consideration in these patients.

Effects of obesity on kidney transplantation outcomes: a systematic review and meta-analysis

BACKGROUND

The effects of obesity on outcomes reported after kidney transplantation have been controversial. The purpose of this systematic review and meta-analysis was to elucidate this issue.

METHODS

MEDLINE, EMBASE, Cochrane Library, and gray literature were searched up to August 6, 2013. Studies that compared obese and nonobese patients who underwent kidney transplantation and evaluated one of these outcomes-delayed graft function (DGF), acute rejection, graft or patient survival at 1 or 5 years after transplantation, or death by cardiovascular disease (CVD)-were included. Two independent reviewers extracted the data and assessed the quality of the studies.

RESULTS

From 1,973 articles retrieved, 21 studies (9,296 patients) were included. Obesity was associated with DGF (relative risk, 1.41; 95% confidence interval, 1.26-1.57; I=8%; Pheterogeneity=0.36), but not with acute rejection. Graft loss and death were associated with obesity only in the analysis of studies that evaluated patients who received a kidney graft before year 2000. No association of obesity with graft loss and death was found in the analysis of studies that evaluated patients who received a kidney graft after year 2000. Death by CVD was associated with obesity (relative risk, 2.07; 95% confidence interval, 1.17-3.64; I=0%; Pheterogeneity=0.59); however, most studies included in this analysis evaluated patients who received a kidney graft after year 2000.

CONCLUSION

In conclusion, obese patients have increased risk for DGF. In the past years, obesity was a risk factor for graft loss, death by CVD, and all-cause mortality. However, for the obese transplanted patient today, the graft and patient survival is the same as that of the nonobese patient.

Long-term mycophenolate monotherapy in human leukocyte antigen (HLA)-identical living-donor kidney transplantation

Although recipients of a first HLA-identical living-donor kidney transplant seem to need less immunosuppression, there are no guideline recommendations for these patients, and few prospective trials are available.

METHODS

We analyzed all PRA-negative patients who received a first kidney transplant from an HLA-identical living donor. The patients received no antibody induction. An intraoperative bolus of 500 mg of methylprednisolone was administered. Then, steroid therapy was withdrawn within one week. Tacrolimus and mycophenolate treatment were started 3 days before transplantation with tacrolimus target levels of 4 to 8 ng/mL. In the absence of rejection, tacrolimus was withdrawn between 3 and 12 months post-transplant to reach mycophenolate mofetil monotherapy of 2 g/day or equivalent.

RESULTS

Six patients were treated with the above protocol. At last follow-up, graft and patient survival were 100%. MDRD glomerular filtration rates were 54, 60, and 62 mL/min at 3 months, 12 months and last follow-up, respectively. None of the patients developed PRA post-transplant. One episode of acute rejection Banff IA occurred 9 years after transplantation due to non-adherence with good outcome after treatment. The mean number of concomitant drugs given with mycophenolate was 2.6. Four patients needed antihypertensive drugs.

CONCLUSION

Steroid-free de novo treatment and calcineurin-inhibitor weaning with mycophenolate monotherapy is feasible in first HLA-identical kidney transplantation from a living sibling.

Genomic biomarkers correlate with HLA-identical renal transplant tolerance

The ability to achieve immunologic tolerance after transplantation is a therapeutic goal. Here, we report interim results from an ongoing trial of tolerance in HLA-identical sibling renal transplantation. The immunosuppressive regimen included alemtuzumab induction, donor hematopoietic stem cells, tacrolimus/mycophenolate immunosuppression converted to sirolimus, and complete drug withdrawal by 24 months post-transplantation. Recipients were considered tolerant if they had normal biopsies and renal function after an additional 12 months without immunosuppression. Of the 20 recipients enrolled, 10 had at least 36 months of follow-up after transplantation. Five of these 10 recipients had immunosuppression successfully withdrawn for 16-36 months (tolerant), 2 had disease recurrence, and 3 had subclinical rejection in protocol biopsies (nontolerant). Microchimerism disappeared after 1 year, and CD4(+)CD25(high)CD127(-)FOXP3(+) regulatory T cells and CD19(+)IgD/M(+)CD27(-) B cells were increased through 5 years post-transplantation in both tolerant and nontolerant recipients. Immune/inflammatory gene expression pathways in the peripheral blood and urine, however, were differentially downregulated between tolerant and nontolerant recipients. In summary, interim results from this trial of tolerance in HLA-identical renal transplantation suggest that predictive genomic biomarkers, but not immunoregulatory phenotyping, may be able to discriminate tolerant from nontolerant patients.

Evolving approaches of hematopoietic stem cell-based therapies to induce tolerance to organ transplants: the long road to tolerance

The immunoregulatory properties of hematopoietic stem cells (HSCs) have been recognized for more than 60 years, beginning in 1945, when Owen reported that genetically disparate freemartin cattle sharing a common placenta were red blood cell chimeras. In 1953, Billingham, Brent, and Medawar demonstrated that murine neonatal chimeras prepared by infusion of donor-derived hematopoietic cells exhibited donor-specific tolerance to skin allografts. Various approaches using HSCs in organ transplantation have gradually brought closer to reality the dream of inducing donor-specific tolerance in organ transplant recipients. Several hurdles needed to be overcome, especially the risk of graft-versus-host disease (GVHD), the toxicity of ablative conditioning, and the need for close donor-recipient matching. For wide acceptance, HSC therapy must be safe and reproducible in mismatched donor-recipient combinations. Discoveries in other disciplines have often unexpectedly and synergistically contributed to progress in this area. This review presents a historic perspective of the quest for tolerance in organ transplantation, highlighting current clinical approaches.

Using donor-specific antibodies to monitor the need for immunosuppression

BACKGROUND

Experience with tolerance protocols has shown that none is perfect and that each escape from tolerance must be identified early to prevent graft failure. In addition, some test is needed for patients who are weaned off immunosuppression (IS) to forewarn of weaning failure. The usual measures of function--such as serum creatinine levels--are not sensitive enough to detect rejection in a timely manner.

METHODS

A study was carried out on 72 patients who received living-donor kidney transplants with clonal deletion protocol (total lymphoid irradiation or bortezomib), and followed with reduced doses of maintenance IS. Every month or every 2 months, a test was performed for donor-specific antibodies (DSA) using Luminex mixed and/or single antigen beads.

RESULTS

After transplantation, DSA developed in 17% of the patients at 6 months, 41% at 1 year, and 57% at 2 years, with 95% confidence limits of 10%, 28%; 30%, 55%; and 44%, 71%, respectively. Fifty-three percent of patients weaned IS to less than 10 mg prednisone daily experienced DSA within 3 months. Furthermore, prednisone dose (per 2.5 mg) and years after transplantation were inversely associated with DSA production (risk ratio 0.92 [95% confidence limits: 0.85, 0.99], and 0.70 [0.49, 1.00]).

CONCLUSIONS

DSA monitoring is highly effective for detecting escape from tolerance and reemergence of the immune response in weaned patients. DSA appearance was inversely proportional to the level of maintenance drugs in the weaning process. Measurement of DSA on a monthly basis is adequate for detection of the change in immune reactivity.