Risks and benefits of weaning immunosuppression in liver transplant recipients: long-term follow-up

Time since liver transplant and immunosuppression withdrawal outcomes: Systematic review and individual patient data meta-analysis

BACKGROUND & AIMS

Successful immunosuppression withdrawal (ISW) is possible for a subfraction of liver transplant (LT) recipients but the factors that define the risk of ISW failure are largely unknown. One candidate prognostic factor for ISW success or operational tolerance (OT) is longer time between LT and ISW which we term "pre-withdrawal time". To clarify the impact of pre-withdrawal time span on subsequent ISW success or failure, we conducted a systematic review with meta-analysis.

METHODS

We systematically interrogated the literature for LT recipient ISW studies reporting pre-withdrawal time. Eligible articles from Embase, Medline, and the Cochrane Central Register of Controlled Trials were used for backward and forward citation searching. Pre-withdrawal time individual patient data (IPD) was requested from authors. Pooled mean differences and time-response curves were calculated using random-effects meta-analyses.

RESULTS

We included 17 studies with 691 patients, 15 of which (620 patients) with IPD. Study-level risk of bias was heterogeneous. Mean pre-withdrawal time was greater by 427 days [95% confidence interval (CI) 67-788] in OT compared to non-OT patients. This increase was potentiated to 799 days (95% CI 369-1229) or 1074 days (95% CI 685-1463) when restricting analysis to adult or European study participants. In time-response meta-analysis for adult or European ISW candidates, likelihood of OT increased by 7% (95% CI 4-10%) per year after LT (GRADE low- and moderate-certainty of evidence, respectively).

CONCLUSIONS

Our data support the impact of pre-withdrawal time in ISW decision-making for adult and European LT recipients.

PROSPERO REGISTRATION

CRD42021272995.

Live Vaccines in Pediatric Liver Transplant Recipients: "To Give or Not to Give"

Content available: Author Audio Recording.

Advances in Liver Transplantation: where are we in the pursuit of transplantation tolerance?

Liver transplantation is the ultimate treatment option for end-stage liver disease. Breakthroughs in surgical practice and immunosuppression have seen considerable advancements in survival after transplantation. However, the intricate management of immunosuppressive regimens, balancing desired immunological quiescence while minimizing toxicity has proven challenging. Diminishing improvements in long-term morbidity and mortality have been inextricably linked with the protracted use of these medications. As such, there is now enormous interest to devise protocols that will allow us to minimize or completely withdraw immunosuppressants after transplantation. Immunosuppression withdrawal trials have proved the reality of tolerance following liver transplantation, however, without intervention will only occur after several years at the risk of potential cumulative immunosuppression-related morbidity. Focus has now been directed at accelerating this phenomenon through tolerance-inducing strategies. In this regard, efforts have seen the use of regulatory cell immunotherapy. Here we focus particularly on regulatory T cells, discussing preclinical data that propagated several clinical trials of adoptive cell therapy in liver transplantation. Furthermore, we describe efforts to further optimize the specificity and survival of regulatory cell therapy guided by concurrent immunomonitoring studies and the development of novel technologies including chimeric antigen receptors and co-administration of low-dose IL-2.

Progress in Liver Transplant Tolerance and Tolerance-Inducing Cellular Therapies

Liver transplantation is currently the most effective method for treating end-stage liver disease. However, recipients still need long-term immunosuppressive drug treatment to control allogeneic immune rejection, which may cause various complications and affect the long-term survival of the recipient. Many liver transplant researchers constantly pursue the induction of immune tolerance in liver transplant recipients, immunosuppression withdrawal, and the maintenance of good and stable graft function. Although allogeneic liver transplantation is more tolerated than transplantation of other solid organs, and it shows a certain incidence of spontaneous tolerance, there is still great risk for general recipients. With the gradual progress in our understanding of immune regulatory mechanisms, a variety of immune regulatory cells have been discovered, and good results have been obtained in rodent and non-human primate transplant models. As immune cell therapies can induce long-term stable tolerance, they provide a good prospect for the induction of tolerance in clinical liver transplantation. At present, many transplant centers have carried out tolerance-inducing clinical trials in liver transplant recipients, and some have achieved gratifying results. This article will review the current status of liver transplant tolerance and the research progress of different cellular immunotherapies to induce this tolerance, which can provide more support for future clinical applications.

Tolerance in clinical liver transplantation

While advances in immunosuppressive therapy have lowered the rate of acute rejection following liver transplantation, the consequence has been an increase in morbidity and mortality related to the lifelong need for maintenance immunosuppression. These complications include an increased risk of malignancy, infection, metabolic disorders, and chronic kidney disease, as well as high health care costs associated with these therapies and the required drug monitoring. Given these issues, most clinicians attempt trial and error dose minimization with variable success rates, and there has been significant interest in full drug withdrawal in select patients through research protocols. These strategies would be more successful if immunomodulatory therapies early after transplantation could be developed and if immune activation biomarkers guiding drug tapering were available to personalize these approaches. This review will review the mechanisms of liver transplant tolerance and potential strategies to achieve immunosuppression withdrawal.

Using a weaning immunosuppression protocol in liver transplantation recipients with hepatocellular carcinoma: a compromise between the risk of recurrence and the risk of rejection?

Hepatocellular carcinoma (HCC) recurrence rate after liver transplantation (LT) is still up to 15-20%, despite a careful selection of candidates and optimization of the management within the waiting list. To reduce tumour recurrence, the currently adopted post-transplant strategies are based on the administration of a tailored immunosuppression (IS) regimen. Drug-induced depression of the immune system is essential in preventing graft rejection, however has a well-established association with oncogenesis. The immune system has a key role as a defending mechanism against cancer development, preventing vascular invasion and metastasis. Thus, IS drugs represent one of few modifiable non-oncological risk factors for tumour recurrence. In HCC recipients, a tailored IS therapy, with the aim to minimize drugs' doses, is essential to gain the optimal balance between the risk of rejection and the risk of tumour recurrence. So far, a complete withdrawal of IS drugs after LT is reported to be safely achievable in 25% of patients (defined as "operational tolerant"), without the risk of patient and graft loss. The recent identification of non-invasive "bio-markers of tolerance", which permit to identify patients who could successfully withdraw IS therapies, opens new perspectives in the management of HCC after LT. IS withdrawal could potentially reduce the risk of tumour recurrence, which represents the major drawback in HCC recipients. Herein, we review the current literature on IS weaning in patients who underwent LT for HCC as primary indication and we report the largest experiences on IS withdrawal in HCC recipients.

Fingerprints of transplant tolerance suggest opportunities for immunosuppression minimization

HLA incompatible organ transplant tolerance is the holy grail of transplantation. Stable engraftment of an HLA mismatched allograft and life-long tolerance induction, though feasible in highly selected cohorts with depletional protocols, is not ready for generalized application to the entire transplant recipient pool. It has thus been important to harness biomarkers that can uncover mechanisms and tools for monitoring HLA mismatched recipients that develop a state of operational tolerance, during accidental immunosuppression withdrawal secondary to problems of over-immunosuppression (infection or malignancy) or toxicity (mostly cosmetic or cardiovascular). A restricted and unpredictable group of patients can demonstrate a clinical state of operational tolerance, manifested by state of stable graft function of a graft with HLA mismatches between recipient and donor, intact immune responses to third party antigens and no measurable immunosuppression. These patients have served as the basis for the discovery of clinically correlative biomarkers, in distal biofluids (mainly blood), that can define the existing state of operational clinical tolerance. Operationally tolerant patients are rare, as withdrawal of immunosuppression most often results in rejection and graft loss. Nevertheless, operationally tolerant kidney, liver and heart allograft recipients have been reported. The presence of similar biomarker signature profiles in HLA mismatched transplant recipients on immunosuppression, suggests the feasibility of utilizing these biomarkers for educated immunosuppression minimization with a view to retaining immunological quiescence, while reducing the maintenance immunosuppression burden to a "safe" alloimmune threshold. Though clinical operational tolerance is rare, as immunosuppression cessation most often results in increased alloimmunity and rejection, the biomarker profile studies that have harnessed whole genome profiling suggest that the frequency of this state may be ~8% in kidney allograft recipients, and even more frequent in pediatric recipients and in liver transplantation: 25% in adult liver allograft recipients and ~60% in pediatric liver allograft recipients. In this review we discuss putative molecular mechanisms, cellular players and correlative biomarkers that have been developed through clinically associative studies of tolerant and non-tolerant patients. Through mechanisms of carefully constructed and monitored randomized, prospective clinical trials, the transplant community stands at the cusp of improved quality of recipient life through educated immunosuppression minimization.

Assessment of chronic rejection in liver graft recipients receiving immunosuppression with low-dose calcineurin inhibitors

BACKGROUND & AIMS

Calcineurin inhibitors represent the cornerstone immunosuppressants after liver transplantation despite their side effects. As liver graft is particularly well tolerated, low doses may be proposed. The aim of this study was to assess the prevalence of chronic rejection in patients with low calcineurin inhibitors regimen and to compare their characteristics with patients under standard doses.

METHODS

All patients with liver transplantation between 1997 and 2004 were divided into two groups. Low-dose patients (n=57) had tacrolimus baseline levels <5ng/ml or cyclosporine levels <50ng/ml at t0 or <100ng/ml at t+2h and were prospectively proposed a liver biopsy, searching for chronic rejection according to Banff criteria. The remaining patients constituted the standard-doses group (n=40).

RESULTS

Among the low-dose group, 36 patients in the low-dose group were assessed by biopsy. No chronic rejection was found. Fifty-six percent had only calcineurin inhibitors and 8% received other immunosuppressants only. The median time between liver transplantation and biopsy was 90 months (64-157) and between IS regimen decrease and biopsy was 41 months (11-115). Liver tests were normal in 72% of the patients. Low-dose patients had more often hepatitis B (p=0.045), less past acute rejection episodes (p=0.028), and better renal function (p=0.040). Decrease of calcineurin inhibitors failed in 15% of standard-dose patients without impacting the graft function. In the low-dose group, co-prescription of other immunosuppressants facilitated the decrease (p=0.051).

CONCLUSIONS

The minimization, or even cessation, of calcineurin inhibitors may be an achievable goal in the long term for most of the liver graft recipients.

Health status in young adults two decades after pediatric liver transplantation

We conducted a cross-sectional study of patients who underwent pediatric liver transplant (LT) between 1988 and 1992 to evaluate long-term health status. Survivors completed socio-demographic, medical and Health-Related Quality of Life (HRQOL) surveys by mail including the SF-36v2, PedsQL™4.0 Generic Core Scale, PedsQL™ Cognitive Functioning Scale and PedsQL™3.0 Transplant Module. SF-36 scores were converted to SF6D-based utilities and risk factors for lower outcomes were assessed. Eighty-five of 171 patients had survived. Fifty-six were contacted with a response rate of 66%. Median age at LT was 0.86 years (IQR 0.58-3.0) and 64.3% had biliary atresia. Mean age at survey was 23.0 ± 4.4 years: 62% attended college, 68% lived with parents and 80% of those over 23 were employed. Patient health utilities were lower than norms (0.75 ± 0.12 vs. 0.82 ± 0.18, p < 0.01) and correlated with unemployment (p < 0.042), hospitalizations (p < 0.005) and lower education level (p < 0.016). Lower PedsQL™3.0 Transplant Module and PedsQL™ 4.0 Generic Core Scale scores correlated with unemployment (p = 0.006, p = 0.009) and hospitalizations (p = 0.006, p = 0.02). Pediatric transplant recipients who survive to adulthood have lower physical HRQOL, measurable transplant-related disability and lower health utility. Transplantation is life saving; however, physical and psychological sequelae continue to affect health status up to two decades later.

Calcineurin inhibitor minimisation versus continuation of calcineurin inhibitor treatment for liver transplant recipients

BACKGROUND

The therapeutic success of liver transplantation has been largely attributable to the development of effective immunosuppressive treatment regimens. In particular, calcineurin inhibitors were essential in reducing acute rejection and improving early survival. Currently, more than 90% of all liver transplant recipients are treated with the calcineurin inhibitor cyclosporine or tacrolimus. Unfortunately, calcineurin inhibitors cause adverse events, such as nephrotoxicity, and because of this, minimisation (reduction and withdrawal) regimens of calcineurin inhibitor have been developed and studied. However, the benefits and harms of these minimisation regimens are unclear.

OBJECTIVES

To assess the benefits and harms of calcineurin inhibitor minimisation for liver transplant recipients without substitution by another immunosuppressive agent.

SEARCH METHODS

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register (Gluud 2010), Cochrane Central Register of Controlled Clinical Trials (CENTRAL) in The Cochrane Library, MEDLINE (OvidSP), EMBASE (OvidSP), Science Citation Index Expanded (Royle 2003), and the World Health Organization (WHO) international clinical trials registry platform (www.who.int/ictrp) until August 2011. In addition, we searched bibliographies of relevant articles as well as US Food and Drug Administration (FDA) and European Medicines Agency (EMA) drug approval reviews for additional trials.

SELECTION CRITERIA

We planned to select all randomised clinical trials investigating calcineurin inhibitor reduction or withdrawal in liver transplant recipients, irrespective of blinding, publication status, or language. Quasi-randomised clinical studies and cohort studies that were obtained through the searches were considered only for the reporting of harms. Trials investigating substitution of one calcineurin inhibitor by another calcineurin inhibitor were excluded. Trials investigating calcineurin inhibitor withdrawal concurrently with switching over to a mammalian target of rapamycin (mTOR) inhibitor-based regimen (everolimus or sirolimus) or mycophenolate mofetil-based regimen are the subject of a separate review.

DATA COLLECTION AND ANALYSIS

Search strategies were used to obtain titles and abstracts of studies that were relevant for the review. Two authors independently scanned the references and assessed trial eligibility.

MAIN RESULTS

A total of 1299 references were identified by the searches. After removal of duplicates, 794 references were left. Out of these, two abstract reports of one ongoing randomised trial fulfilled the inclusion criteria of the review. This ongoing trial studies total withdrawal of immunosuppression in patients who receive a calcineurin inhibitor (cyclosporine or tacrolimus) or mycophenolate mofetil as the only immunosuppressive agent. The trial compares withdrawal of calcineurin inhibitor or mycophenolate mofetil with continuation of calcineurin inhibitor or mycophenolate mofetil. However, no trial results on the outcomes of interest to this review were available.

AUTHORS' CONCLUSIONS

This review shows that strategies regarding calcineurin inhibitor minimisation, that is, reduction or withdrawal, without substitution versus continuation of calcineurin inhibitor treatment lack evidence from randomised trials.More research with calcineurin inhibitor reduction and withdrawal regimens is needed to optimise dosing and timing of calcineurin inhibitor treatment in order to achieve optimal patient and graft survival with a minimum of adverse events.Specifically regarding calcineurin inhibitor reduction versus no reduction, we recommend that randomised trials evaluating calcineurin inhibitor reduction versus continuation of calcineurin inhibitor treatment are conducted.Regarding calcineurin inhibitor withdrawal, we recommend that mechanisms for tolerance and 'graft acceptance' are clarified, and patient groups likely to tolerate calcineurin inhibitor withdrawal are identified in order to select the right patients for total withdrawal of calcineurin inhibitors without substitution with another immunosuppressive drug. The randomised trials should only be performed in highly selected patients.

Operational tolerance: past lessons and future prospects

Every liver transplant (LT) center has had patients who either self-discontinue immunosuppressive (IS) therapy or are deliberately withdrawn due to a research protocol or clinical concern (ie, lymphoproliferative disorder [LPD], overwhelming infection). This is understandable because maintenance IS therapy, particularly calcineurin inhibitors (CNI), is associated with significant cost, side effects, and considerable long-term morbidity and mortality. Detrimental effects of IS therapy include increased risk of cardiovascular disease, metabolic syndrome, bone loss, opportunistic and community-acquired infections, and malignancy. In fact, LT recipients have among the highest rates of chronic kidney disease and associated mortality among all nonkidney solid organ recipients. This mortality is only ameliorated by undergoing a curative kidney transplant, usurping costs and valuable organ resources. The search for improved treatment algorithms includes trial and error CNI dose minimization, the use of alternative IS agents (antimetabolites, mammalian target of rapamycin [mTOR] inhibitors), or even complete CNI withdrawal. Yet those who are successful in achieving such operational tolerance (no immunosuppression and normal allograft function) are considered lucky. The vast majority of recipients will fail this approach, develop acute rejection or immune-mediated hepatitis, and require resumption of IS therapy. As such, withdrawal of IS following LT is not standard-of-care, leaving clinicians to currently maintain transplant patients on IS therapy for life. Nonetheless, the long-term complications of all IS therapies highlight the need for strategies to promote immunologic or operational tolerance. Clinically applicable biomarker assays signifying the potential for tolerance as well as tolerogenic IS conditioning are invariably needed if systematic, controlled rather than "hit or miss" approaches to withdrawal are considered. This review will provide an overview of the basic mechanisms of tolerance, particularly in relation to LT, data from previous IS withdrawal protocols and biomarker studies in tolerant recipients, and a discussion on the prospect of increasing the clinical feasibility and success of withdrawal.

Withdrawal of immunosuppression in pediatric liver transplant recipients in Korea

PURPOSE

We identified pediatric liver transplant recipients with successful withdrawal of immunosuppression who developed tolerance in Korea.

MATERIALS AND METHODS

Among 105 pediatric patients who received liver transplantation and were treated with tacrolimus-based immunosuppressive regimens, we selected five (4.8%) patients who had very low tacrolimus trough levels. Four of them were noncompliant with their medication and one was weaned off of immunosuppression due to life threatening posttransplant lymphoproliferative disorder. We reviewed the medical records with regard to the relationship of the donor-recipients, patient characteristics and prognosis, including liver histology, and compared our data with previous reports.

RESULTS

Four patients received the liver transplantation from a parent donor and one patient from a cadaver donor. A trial of withdrawal of the immunosuppressant was started a median of 45 months after transplantation (range, 14 months to 60 months), and the period of follow up after weaning from the immunosuppressant was a median of 32 months (range, 14 months to 82 months). None of the five patients had rejection episodes after withdrawal of the immunosuppression; they maintained normal graft function for longer than 3 years (median, 38 months; range, 4 to 53 months). The histological findings of two grafts 64 and 32 months after weaning-off of the medication showed no evidence of chronic rejection.

CONCLUSION

The favorable markers for successful withdrawal of immunosuppression were 1) long-term (> 3 years) stable graft function, 2) no rejection for longer than 1 year after withdrawal of immunosuppression, 3) non-immune mediated liver diseases, and 4) pediatric patients.

Immunoregulatory profiles in liver transplant recipients on different immunosuppressive agents

We compared peripheral blood immunophenotyping in 31 adult liver transplant recipients on differing long-term immunosuppressive (IS) monotherapy with and without peri-transplantation alemtuzumab (AL) induction. All patients had been stable on monotherapy with either sirolimus (SRL) (n = 10) or without SRL (tacrolimus (TAC) (n = 10), mycophenolate mofetil (MMF) (n = 11)) for more than 6 months. Five-color flow cytometry for putative "regulatory" T and dendritic cells as well as serum assays for soluble HLA-G (sHLA-G) were performed. The SRL monotherapy group had significantly higher percentages of CD4+CD25(high+)Foxp3+ T cells (1.3 +/- 1.0) compared with the non-SRL group (0.7 +/- 0.6) (p = 0.04). The SRL effect was even higher in a subset with prior AL induction and no prior hepatitis C or rejection (1.7 +/- 0.2) compared with all other subgroups (0.7 +/- 0.6) (p = 0.02). TAC patients showed significantly higher "regulatory" DC2:DC1 ratios (10 +/- 7.6) compared with non-TAC patients (4.1 +/- 2.3) (p = 0.04). Although sHLA-G levels appeared higher in TAC patients, the differences were not statistically significant. In conclusion, IS monotherapy provides an opportunity to investigate regulatory roles of individual agents. SRL maintenance and prior AL induction in subsets of patients appeared to show a regulatory T cell immunophenotype. However, TAC patients may have other regulatory characteristics, supporting the need for larger, prospective studies to clarify differences.

Early days of liver transplantation

The early days of liver transplantation were exciting, demanding, subject to terrible disappointments and sadness but occasional elation, and a gradual understanding of the factors necessary to achieve a satisfactory operation. In addition, care of an extremely sick patient, the management of the disease, especially if it was infectious or malignant, and the support of the relatives and the transplant team, required a group of loyal, dedicated and above all optimistic members who could see through the repeated unhappy outcomes that eventually most of the problems would be solved. This in fact has come to pass.

Prope tolerance--the future of organ transplantation from the laboratory to the clinic

This is a short review of tolerance from the point of view of the clinician. Various examples of tolerance occurring in patients and animal models that relate to the clinical experience are described. It is suggested that there may be different mechanisms by which tolerance is achieved, but, from the patient's point of view operational, tolerance is the goal whereby, after a short induction procedure, the patient will maintain good function in the grafted organ indefinitely without maintenance immunosuppression. It is pointed out that such a goal may be difficult to achieve with any given protocol due to the enormous variation between donors and recipients of organ grafts of tissue matching, innate immune reactivity, and susceptibility to disturbance of a tolerant state by infections or allergic reactions. Thus, the case is made for prope or almost tolerance in which graft acceptance is maintained by a low, nontoxic dosage of maintenance immunosuppression which may not be required indefinitely.

Reduction of immunosuppression for transplant-associated skin cancer: rationale and evidence of efficacy

BACKGROUND

Solid organ transplant recipients may develop numerous or life-threatening skin cancers. In addition to aggressive standard treatment of skin cancer, reduction of immunosuppression has been considered an adjuvant therapeutic strategy, albeit without direct proof of efficacy.

OBJECTIVE

To review the rationale for and evidence supporting the efficacy of reduction of immunosuppression for severe skin cancer in transplant recipients.

METHODS

Review of the literature regarding direct and indirect evidence on reduction of immunosuppression for transplant-associated skin cancer.

RESULTS

Although there are no randomized controlled trials of reduction of immunosuppression as a therapeutic intervention for transplant patients with skin cancer, multiple lines of evidence suggest that this strategy may be an effective adjuvant therapy. A randomized trial has demonstrated a lower incidence of skin cancer in transplant recipients after reduction of immunosuppression, albeit in a cohort not previously affected by skin cancer. Case series of reduction or cessation of immunosuppression demonstrate a lower incidence of skin cancer or improved outcomes of preexisting skin cancer. Lower overall immunosuppression is associated with a lower incidence of skin cancer. Multiple cancers affecting the skin have been shown to regress with reduction of immunosuppression.

CONCLUSIONS

Reduction of immunosuppression may be an effective adjuvant therapeutic strategy when confronting severe transplant-associated skin cancer. The risks of reduction of immunosuppression must be better defined, and randomized trials of this strategy are necessary.

Impaired neutralising antibody formation and high transduction efficacy after isolated hepatic perfusion with adenoviral vectors

Local adenoviral gene transfer can be performed by means of isolated hepatic perfusion (IHP). This methodology is a very effective and safe way to deliver adenoviral vectors. We studied the immune response after IHP. A decreased neutralising antibody formation was observed, offering possibilities for further research in the field of gene therapy in isolated perfusion settings.

Prope tolerance—the future of organ transplantation from the laboratory to the clinic

This is a short review of tolerance from the point of view of the clinician. Various examples of tolerance occurring in patients and animal models that relate to the clinical experience are described. It is suggested that there may be different mechanisms by which tolerance is achieved, but from the patient's point of view operational tolerance is the goal whereby, after a short induction procedure, the patient will maintain good function in the grafted organ indefinitely without maintenance immunosuppression. It is pointed out that such a goal may be difficult to achieve with any given protocol due to the enormous variation between donors and recipients of organ grafts of tissue matching, innate immune reactivity and susceptibility to disturbance of a tolerant state by infections or allergic reactions. Thus, the case is made for prope or almost tolerance in which graft acceptance is maintained by a low, non-toxic dosage of maintenance immunosuppression, which may not be required indefinitely.

The concept of “partial” clinical tolerance

The status of "partial" tolerance to organ allografts versus the status of complete tolerance is the main topic of this paper. Progress made in immunosuppression, particularly by use of various lymphocyte depleting agents for "induction therapy", seems to favor the subsequent development of T cells with suppressor/regulatory properties. The effective deletion of alloreactive T helper and cytotoxic cells in conjunction with the expansion of antigen-specific suppressor (CD8 + CD28 - FOXP3+) and regulatory (CD4 + CD25+ FOXP3+) T cells creates a milieu in which the graft is well tolerated under an "umbrella" of low dosage immunosuppression. The most effective induction treatment is Campath-1H, although ATGAM at high dosage is also widely used. Total lymphoid irradiation (TLI) is another very effective pretreatment strategy in spite of the risks which are associated with it. The induction of "partial" tolerance is a step in the right direction for exploring strategies that may lead to the induction of complete tolerance. It is safe for the patients and can prolong significantly the function of the graft, preventing the onset of chronic rejection.

Guidelines for the management of squamous cell carcinoma in organ transplant recipients

BACKGROUND

Solid-organ transplant recipients have a high incidence of cutaneous squamous cell carcinoma (SCC) and often develop multiple and aggressive tumors. There are few published studies or reviews, which provide guidance to the clinician in the treatment of these patients.

OBJECTIVE

The objective was to develop useful clinical guidelines for the treatment of skin cancer in organ transplant recipients (OTRs).

METHODS

The members of the Guidelines Committee of the International Transplant-Skin Cancer Collaborative (ITSCC) carried out a computerized search utilizing the databases of the National Library of Medicine for reports in the literature on SCC in OTRs. These reports were collectively examined by the group and combined with experiences from the members' clinical practices in the development of the guidelines.

RESULTS

More than 300 articles relating to SCC in OTRs were reviewed. In general, reports concerning the prevention and treatment of SCC in OTRs are of individual cases or small case series. They are retrospective in nature, statistically nonrigorous, and lack the complete epidemiologic data necessary to derive definitive conclusions. Combining these studies and collective clinical experience, however, is at present the best available method for devising guidelines for the treatment of SCC in OTRs.

CONCLUSION

Guidelines developed for the treatment of skin cancer in OTRs, supported by the best available data and collective clinical experience, may assist in the management of OTRs with SCC. The development of clinical pathways and complete documentation with rigorous prospective study is necessary to improve and refine future guideline development.

Prope tolerance: the future of organ transplantation--from the laboratory to the clinic

This is a short review of tolerance from the point of view of the clinician. Various examples of tolerance occurring in patients and animal models that relate to the clinical experience are described. There may be different mechanisms by which tolerance is achieved, but from the patient's point of view operational tolerance is the goal whereby, after a short induction procedure, the patient will maintain good function in the grafted organ indefinitely without maintenance immunosuppression. Such a goal may be difficult to achieve with any given protocol because of the enormous variation between donors and recipients of organ grafts in tissue matching, innate immune reactivity, and susceptibility to disturbance of a tolerant state by infections or allergic reactions. Thus the case is made for prope or "almost" tolerance in which graft acceptance is maintained by a low, nontoxic dosage of maintenance immunosuppression that may not be required indefinitely.

Clinical islet transplant: current and future directions towards tolerance

The ultimate goal of islet transplantation is to completely correct the diabetic state from an unlimited donor source, without the need for chronic immunosuppressive drug therapy. Although islet transplantation provides an opportunity to develop innovative strategies for tolerance in the clinic, both alloimmune and autoimmune barriers must be controlled, if stable graft function is to be maintained long-term. After islet extraction from the pancreas, the cellular graft may be stored in tissue culture or cryopreserved for banking, providing an opportunity not only to optimally condition the recipient but also to allow in vitro immunologic manipulation of the graft before transplantation, unlike solid organ grafts. As such, islets may be considered a "special case." Remarkable progress has occurred in the last three years, with dramatic improvements in outcomes after clinical islet transplantation. The introduction of a steroid-free, sirolimus-based, anti-rejection protocol and islets prepared from two (or rarely three) donors led to high rates of insulin independence. The "Edmonton Protocol" has been successfully replicated by other centers in an international multicenter trial. A number of key refinements in pancreas transportation, processing, purification on non-ficoll-based media, storage of islets in culture for two days and newer immunological conditioning and induction therapies have led to continued advancement through extensive collaboration between key centers. This review outlines the historical development of islet transplantation over the past 30 years, provides an update on current clinical outcomes, and summarizes a series of unique opportunities for development and early testing of tolerance protocols in patients.

Reasons for long-term use of steroid in primary adult liver transplantation under tacrolimus

BACKGROUND

Tacrolimus is a potent immunosuppressive agent that provides higher freedom from acute and chronic rejection than cyclosporine after liver transplantation (LTx). Initially, a steroid-free state was observed in about 70% of patients at 1 year; this did not change over the next 5 years. The present study identifies the various reasons why the remaining 30% of adult patients still require steroids even after 5 years after successful LTx.

METHOD

Eight hundred thirty-four consecutive patients who underwent LTx between August 1989 and December 1992 were included in this study. Four hundred ninety-nine patients were alive in January 1999 and were available for this study. The dose of steroid and the reason for steroid use were retrospectively determined from the clinical records.

RESULTS

Three hundred sixty-five patients (73.1%) were off steroid, whereas 134 patients (26.9%) were receiving prednisone (mean dose was 6.4+/-3.7 mg/day) at the time of the study. Four hundred and eight-four patients (97%) were off prednisone at some time after LTx; however, in 119 (23.8%) patients, steroids were reintroduced. Fifteen patients (3%) continued to receive prednisone; eight receive prednisone due to reluctance of the local physician to withdraw the medication; in five patients, the prednisone was not withdrawn because these patients were on cyclosporine; in the remaining two patients, repeated attempts to withdraw steroid resulted in a rise in liver function test. In the 49 (36.6%) of 119 patients in whom the steroid was reintroduced, it was restarted secondary to pathologically proven or clinically suspected rejection (group I). In five patients steroid was reintroduced for abnormal liver function after being off immunosuppression for treatment of a posttransplantation lymphoproliferative disorder. Six patients were noncompliant with their immunosuppressive medication, and the steroid was reintroduced to control rejection. Steroids were reintroduced in 30 patients (22.4%) for recurrence of original disease: primary biliary cirrhosis (n= 19), sclerosing cholangitis (n=6), and autoimmune hepatitis (n=5) (group II). In 24 patients (20.2%), steroids were reintroduced to lower the dose of tacrolimus secondary to nephrotoxicity. Six of these patients received kidney transplantation (group III). In 16 patients (13.4%) the steroid was reintroduced for concomitant medical problems, consisting of ulcerative/Crohn's colitis (n=6), adrenal insufficiency (n=5), hematological disorders (n=3), dermatitis (n=1), and rheumatoid arthritis (n=1) (group IV).

CONCLUSION

Ninety-seven percent of patients under tacrolimus were weaned off steroid; however, 23.8% required steroid reintroduction for late rejection, recurrence of autoimmune process(es), renal impairment, or the concomitant presence of other medical conditions. Although the use of other immunosuppressive agents may reduce the rate of reintroduction of steroid, long-term sustained freedom from steroid may not be possible in all patients under tacrolimus secondary to these conditions.

Reasons why some children receiving tacrolimus therapy require steroids more than 5 years post liver transplantation

Tacrolimus is a potent immunosuppressive agent and has been used in liver transplantation (LTx) for nearly a decade. More than 70% of children can be maintained on tacrolimus monotherapy, without steroids, by the end of 1 yr post-Tx. This freedom from steroids does not appear to change significantly in subsequent years. The use of steroids has obvious metabolic and cosmetic disadvantages, besides affecting linear growth in children. The present study identifies why some children still require steroid therapy after successful LTx. One hundred and sixty-six consecutive pediatric patients who had undergone primary LTx between October 1989 and December 1992, were included in this study. Follow-up ranged from 6 to 9 yr (mean 7.5 +/- 0.8 yr). One hundred and forty-one children were alive in November 1998 and these patients constituted the study group. Their current rate of prednisone use, reason for prednisone use, and prednisone dose were examined retrospectively. Of the 141 patients, 139 (98.5%) had stopped taking steroids at some time-point after LTx. Thirteen patients (9%) were off immunosuppression altogether (group I), 97 were undergoing tacrolimus monotherapy (group II), and the remaining 31 were receiving therapy with steroids and tacrolimus (group III). The mean prednisone dose at the last follow-up was 6.5 +/- 4.9 mg/day (median 5.0 mg/day). In group III, two children were never weaned off steroids because of inadequate follow-up (both lived outside the country), and the remaining 29 children completely stopped steroid therapy at some time-point after LTx; however, prednisone was re-introduced for clinically suspected or biopsy-proven rejection in 24. Seven children in group III had completely stopped immunosuppressive therapy either as part of an immunosuppression reduction protocol (n = 3) or for suspected or proven post-transplant lymphoproliferative disorder (PTLD) (n = 4). In eleven of the 18 children in group III, requirement of steroid for rejection was thought to be related, in part, to non-compliance. In three children in group III, steroids were re-introduced for renal dysfunction, and two of these patients subsequently received a kidney Tx. In one child with cerebral ischemia, steroids were used to reduce brain edema, and another child had features of auto-immune hepatitis. Hence, almost all children can be weaned off steroids when tacrolimus is used as primary immunosuppression after primary LTx. However, approximately 22% of children may need re-institution of steroids because of late acute rejection or renal dysfunction. The concomitant use of other non-steroidal immunosuppressive agents with tacrolimus may further reduce the dose and rate of steroid use.