Minimization of steroids in liver transplantation

New insights in immunomodulation for intestinal transplantation

Tolerance is the Holy Grail of solid organ transplantation (SOT) and remains its primary challenge since its inception. In this topic, the seminal contributions of Thomas Starzl at Pittsburgh University outlined foundational principles of graft acceptance and tolerance, with chimerism emerging as a pivotal factor. Immunologically, intestinal transplantation (ITx) poses a unique hurdle due to the inherent characteristics and functions of the small bowel, resulting in increased immunogenicity. This necessitates heavy immunosuppression (IS) while IS drugs side effects cause significant morbidity. In addition, current IS therapies fall short of inducing clinical tolerance and their discontinuation has been proven unattainable in most cases. This underscores the unfulfilled need for immunological modulation to safely reduce IS-related burdens. To address this challenge, the Leuven Immunomodulatory Protocol (LIP), introduced in 2000, incorporates various pro-tolerogenic interventions in both the donor to the recipient, with the aim of facilitating graft acceptance and improving outcome. This review seeks to provide an overview of the current understanding of tolerance in ITx and outline recent advances in this domain.

Metabonomic Profile of Macrosteatotic Allografts for Orthotopic Liver Transplantation in Patients With Initial Poor Function: Mechanistic Investigation and Prognostic Prediction

BACKGROUND

Our previous study revealled amplified hazardous effects of macrosteatosis (MaS) on graft failure (GF) in recipients with severe liver damage in short post-operative days, with vague mechanism inside.

AIM

We aimed to uncover the molecular mechanism of donor MaS on GF, and construct the predictive model to monitor post-transplant prognosis based on "omics" perspective.

METHODS

Ultra-performance liquid chromatography coupled to mass spectrometry metabolomic analysis was performed in allograft tissues from 82 patients with initial poor function (IPF) from multi-liver transplant (LT) centers. Pathway analysis was performed by on-line toolkit Metaboanalyst (v 3.0). Predictive model was constructed based on combinative metabonomic and clinical data extracted by stepwised cox proportional analysis.

RESULTS

Principle component analysis (PCA) analysis revealled stratification on metabolic feature in organs classified by MaS status. Differential metabolits both associated with MaS and GF were significantly enriched on pathway of glycerophospholipid metabolism (P < 0.05). Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) involved in glycerophospholipid metabolism was significantly decreased in cases with MaS donors and GF (P < 0.05). Better prediction was observed on graft survival by combinative model (area under the curve = 0.91) and confirmed by internal validation.

CONCLUSION

Metabonomic features of allografts can be clearly distinguished by MaS status in patients with IPF. Dysfunction on glycerophospholipid metabolism was culprit to link donor MaS and final GF. Decrement on PC and PE exerted the fatal effects of MaS on organ failure. Metabonomic data might help for monitoring long-term graft survival after LT.

Clinical Operational Tolerance and Immunosuppression Minimization in Kidney Transplantation: Where Do We Stand?

BACKGROUND

The 20th century represents a breakthrough in the transplantation era, since the first kidney transplantation between identical twins was performed. This was the first case of tolerance, since the recipient did not need immunosuppression. However, as transplantation became possible, an immunosuppression-free status became the ultimate goal, since the first tolerance case was a clear exception from the hard reality nowadays represented by rejection.

METHODS

A plethora of studies was described over the past decades to understand the molecular mechanisms responsible for rejection. This review focuses on the most relevant studies found in the literature where renal tolerance cases are claimed. Contrasting, and at the same time, encouraging outcomes are herein discussed and a glimpse on the main renal biomarkers analyzed in this field is provided.

RESULTS

The activation of the immune system has been shown to play a central role in organ failure, but also it seems to induce a tolerance status when an allograft is performed, despite tolerance is still rare to register. Although there are still overwhelming challenges to overcome and various immune pathways remain arcane; the immunosuppression minimization might be more attainable than previously believed.

CONCLUSION

. Multiple biomarkers and tolerance mechanisms suspected to be involved in renal transplantation have been investigated to understand their real role, with still no clear answers on the topic. Thus, the actual knowledge provided necessarily leads to more in-depth investigations, although many questions in the past have been answered, there are still many issues on renal tolerance that need to be addressed.

Longterm Survival and Cost-Effectiveness of Immunosuppression Withdrawal After Liver Transplantation

Lifelong immunosuppression (IS) after liver transplantation is associated with severe adverse effects and increased recipients' morbidity and mortality. Clinical operational tolerance has been reported in up to 40% in very well-selected recipients. Longterm survival and cost savings within the Italian national health system in operational tolerant recipients is reported. Seventy-five liver recipients were enrolled for IS withdrawal at our institution during the period from April 1998 to December 2015. The study population comprised 32 (42.7%) tolerant patients; 41 (54.7%) nontolerant patients needing uptake of IS after clinical or biopsy-proven rejection; and 2 (2.7%) immediate nontolerant patients who developed early rejection after the first drug reduction. The primary endpoint of the study was to assess the longterm patients and graft outcome; the secondary endpoint was the assessment of cost savings in the context of IS withdrawal. The follow-up was 95.0 months (interquartile range, 22.5-108.5 months). IS withdrawal did not result in patient nor graft loss and resulted in a major cost savings reaching about €630,000. In conclusion, longterm IS withdrawal represents a remarkable cost savings in the health care of liver recipients without exposing them to graft loss.

Is minimal, [almost] steroid-free immunosuppression a safe approach in adult liver transplantation? Long-term outcome of a prospective, double blind, placebo-controlled, randomized, investigator-driven study

OBJECTIVE

To investigate the safety of minimal immunosuppression (IS) in liver transplantation (LT).

BACKGROUND

The lack of long-term follow-up studies, including pathologic data, has led to a protean handling of IS in LT.

METHODS

Between February 2000 and September 2004, 156 adults were enrolled in a prospective, randomized, double-blind, placebo-controlled minimization trial comparing tacrolimus placebo (TAC-PLAC) and TAC short-term steroid (TAC-STER) IS. All patients had a minimum clinical, biochemical, and histological follow-up of 5 years.

RESULTS

Five-year actual patient and graft survival rates in TAC-PLAC and TAC-STER groups were 78.1% and 82.1% (P=0.89) and 74.2% and 76.9% (P=0.90), respectively. Five-year biopsies were available in 112 (89.6%) of 125 survivors. Twelve patients refused a biopsy because of their excellent evolution; tissue material was insufficient in 1 patient; 11 had normal liver tests; and 2 patients had developed alcoholic and secondary biliary cirrhosis. Histology was normal in 44 (39.3%) patients; 35 (31.3%) had disease recurrence. The remaining biopsies showed nonspecific chronic hepatitis (14.3%), mild inflammatory infiltrates (10.7%), and steatosis (3.5%). All findings were equally distributed between both groups. In each group, 3 patients (4.8%) presented with acute cellular rejection after the first year and only 1 (0.9%) TAC-PLAC patient developed chronic rejection after IS withdrawal because of pneumonitis. Arterial hypertension, diabetes mellitus, renal insufficiency, hypercholesterolemia, gout, and obesity were equally low in both groups.

CONCLUSIONS

Excellent long-term results can be obtained under minimal IS and absence of steroids. TAC-based monotherapy is feasible in most adult liver recipients until 5 years of follow-up.

Steroid-free and steroid withdrawal protocols in heart transplantation: the review of literature

Corticosteroids (CSs) are still the mainstay of induction, rescue, and maintenance in heart transplantation (HTx). However, their use is associated with significant and well-documented side effects usually related to the dose administered and the duration of therapy. Moreover, CSs interfere with the recipient's quality of life and with the active process of graft tolerance. Physicians have been exploring ways to avoid or reduce CSs in association with other immunosuppressive drugs, minimizing side effects and costs. The regimens are classified as steroid-free or steroid withdrawal protocols. The studies analyzed in this review come to similar conclusions as benefits and adverse consequences: steroid-free protocols should be advisable and mandatory in pediatric patients, insulin-dependent diabetes mellitus (IDDM), presence of infection, familial metabolic disorders/obesity, severe osteoporosis, and in the elderly. On the other hand, steroid withdrawal can be successfully achieved in 50-80%, with late better than early withdrawal, no increase in rejection-related mortality, no adverse impact on survival, and probably a better quality of live. Safety and efficacy can certainly be improved by an individualized approach to the transplant recipient.

Immunosuppression minimization vs. complete drug withdrawal in liver transplantation

Despite the increase in long-term survival, liver transplant recipients still exhibit higher morbidity and mortality than the general population. This is in part attributed to the lifelong administration of immunosuppression and its associated side effects. Several studies reported in the last decades have evaluated the impact of immunosuppression minimization in liver transplant recipients, but results have been inconsistent due to the heterogeneity of study designs and insufficient sample sizes. On the other hand, complete immunosuppression withdrawal has proven to be feasible in approximately 20% of carefully selected liver transplant recipients, especially in older patients and those with longer duration after transplantation. The long-term risks and clinical benefits of this strategy, however, also need to be clarified. As a consequence, and despite the general perception that a large proportion of liver recipients are over-immunosuppressed, it is currently not possible to derive evidence-based guidelines on how to manage long-term immunosuppression to improve clinical outcomes. Large clinical trials of drug minimization and/or withdrawal focused on clinically-relevant long-term outcomes are required. Development of personalized medicine tools and a deeper understanding of the pathogenesis of idiopathic inflammatory graft lesions will be pre-requisites to achieve these goals.

Early steroid withdrawal regimen prevents new-onset diabetes mellitus in old-age recipients after living donor liver transplantation

BACKGROUND

Steroid use after liver transplantation is known to increase the risk of new-onset diabetes mellitus (NODM). In this study, we tried to identify a patient subgroup who would benefit with regard to NODM by an early steroid withdrawal regimen (ESWR) after living donor liver transplantation (LDLT) METHODS: Among 100 adult LDLT patients, 65 were on a conventional immunosuppressive regimen (CIR), and 35 were on an ESWR. With the ESWR, the steroid was tapered off mostly within 7 days with induction of basiliximab in combination with tacrolimus and mycophenolate mofetil (MMF). The CIR was a combination of tacrolimus and steroid. MMF was added in selected patients. Steroid was tapered off 2-6 months after LT. The presence of NODM was investigated cross-sectionally 6 months after LT.

RESULTS

There was no significant difference in terms of acute cellular rejection, sepsis, or death during follow-up. NODM had developed in 13 patients (13 %). Old recipient age (≥ 55) and pretransplant history of hypertension were significant risk factors for NODM. The type of immunosuppression was the single risk factor for NODM in subgroup of old-age recipients (≥ 55 years) on the CIR (hazard ratio 13.34, p = 0.04).

CONCLUSIONS

ESWR can safely reduce the incidence of NODM after LDLT in old-age recipients. Therefore, ESWR should be considered first in old-age recipients undergoing LDLT.

The Tor Vergata weaning of immunosuppression protocols in stable hepatitis C virus liver transplant patients: the 10-year follow-up

We report herein the 10-year outcome of the Tor Vergata weaning off immunosuppression protocol in hepatitis C virus (HCV) liver transplant patients. Thirty-four patients who had received a liver graft for HCV-related cirrhosis were enrolled in a prospective study in which they were progressively weaned off immunosuppression. The primary endpoints were feasibility and safety of the weaning; the second aim was to assess fibrosis progression. At the 10-year follow-up, of the eight original tolerant patients, six remained IS-free. Of the 26 individuals who could not be weaned, 22 were alive. When the baseline biopsies were compared with the 10-year biopsies, the tolerant group showed no differences in staging, whereas the nontolerant group showed a significant increase in staging. The fibrosis progression rates calculated for the tolerant and the nontolerant groups were -0.06 ± 0.12 and 0.1 ± 0.2, respectively (P = 0.04). Furthermore, with the last taken biopsies, nine nontolerant patients were showing frank cirrhosis versus no cirrhosis among the tolerant patients. After a 10-year follow-up of a Tor Vergata weaning protocol, 6/34 patients completed follow-up without reinstitution of immunosuppression and this appeared beneficial regarding a reduction in fibrosis progression.

Safety and efficacy of four steroid-minimization protocols in liver transplant recipients: 3-year follow-up in a single center

OBJECTIVE

To evaluate the safety and efficacy of steroid-minimization therapy in liver transplantation (LT) recipients with hepatitis B virus-related diseases in China.

METHODS

From March 2000 to June 2007, 502 adult LT recipients, mostly with hepatitis B (HBV)-related diseases, were enrolled in our study. Four study groups were setup according to the steroid-minimization protocols: tacrolimus (TAC) with 6 months steroids withdrawal (6M SW), TAC with 3 months SW (3M SW), TAC with 14 days SW (14d SW), and TAC with basiliximab induction and steroids avoidance (Bas SA). All patients were followed up for at least 36 months after LT.

RESULTS

There were no significant differences in the overall 3-year survival rates of the patients and graft, and chronic rejection among the four groups (P = 0.092, P = 0.113 and P = 0.684, respectively). There was also no difference in acute rejection within 12 months after LT (P = 0.514). The 3-year recurrence rates of HBV infection and hepatocellular carcinoma (HCC) after LT were significantly different among all the groups (lowest in TAC/Bas SA group; P = 0.037 and P = 0.029, respectively). The overall incidence of infection was significantly higher in the 6M SW group (62.2% vs 56.1% in 3M SW, 30.5% in 14d SW, 20.5% in Bas SA; P < 0.01). By the end of the 3-year follow-up, more than 90% of the surviving patients could safely receive TAC monotherapy.

CONCLUSION

Bas SA immunosuppressive protocol can be achieved safely in LT and reduce HBV infection and HCC recurrence and side effects of steroids after LT.

The impact of early corticosteroid withdrawal on graft survival in liver transplant recipients

BACKGROUND

There has been increased interest in recent years in reducing or eliminating steroids from the immunosuppression regimen of transplant recipients to reduce adverse effects associated with their use. The purpose of this study was to compare clinical outcomes between early versus late steroid withdrawal after liver transplant to determine the optimal duration of steroid use in this population.

METHODS

This large-scale, retrospective analysis of liver transplants occurred at our institution between 2000 and 2009. Patients were excluded if they were <18 years old, received a multiorgan transplant, or remained on steroids for >1 year. The early steroid withdrawal group had steroids eliminated by 3 months posttransplant; late steroid withdrawal patients had steroids withdrawn between 3 and 12 months posttransplant.

RESULTS

A total of 586 liver transplants occurred during the study period; 330 patients were included in the analysis. Graft survival was significantly lower in the early steroid withdrawal group. There was no difference in patient survival or overall acute rejection. However, the late steroid withdrawal group had a significantly higher rate of early acute rejection episodes. There was no difference with regard to new-onset diabetes after transplant, hyperlipidemia, or cardiovascular events between groups.

CONCLUSION

The results of this study suggest that late corticosteroid withdrawal is associated with better long-term graft survival without increasing the rates of diabetes, hyperlipidemia, or cardiovascular events in liver transplant recipients. A prospective study is warranted to confirm these findings.

Liver transplantation for hepatocellular cancer: UCL experience in 137 adult cirrhotic patients. Alpha-foetoprotein level and locoregional treatment as refined selection criteria

Liver transplantation (LT) is a validated treatment for selected cirrhotics with hepatocellular cancer (HCC). A retrospective single center study including 137 recipients having proven HCC was done to refine inclusion criteria for LT as well as to look at impact of locoregional treatment (LRT) on outcome. At pre-LT imaging, 42 (30.6%) patients were Milan criteria (MC)-OUT; 28 (20.4%) were University of California San Francisco criteria (UCSFC)-OUT. Pre-LT LRT was performed in 109 (79.6%) patients. Multivariate analysis identified four factors to be independently predictive of recurrence: tumour number >3, AFP level ≥400 ng/ml, microvascular invasion and rejection needing anti-lymphocytic antibodies. When considering pre-transplant variables only, AFP level ≥400 ng/ml (HR = 5.13; P < 0.0001) was the unique risk factor for recurrence; conversely, application of LRT was protective (HR = 0.42; P = 0.04). MC-IN patients having LRT (n = 79) had the best 5-year tumour-free survival (TFS) (91.6%). MC-IN patients without LRT (n = 16) and MC-OUT patients with LRT (n = 30) had similar good TFS (72.7% vs.77.5%); finally MC-OUT patients without LRT (n = 12) had the worst results (45.0%; vs. 1st group: P < 0.0001). Immediate pre-LT AFP and aggressive pre-transplant LRT strategy, especially in MC-OUT patients, are both important elements to further expand inclusion criteria without compromising long-term results of HCC liver recipients.

The failure of immunosuppression withdrawal: patient benefit is not detectable, inducible, or reproducible

(1) Immunosuppression is responsible for excellent patient outcomes. (2) Immunosuppression withdrawal fails in most patients. (3) Patients who may benefit from immunosuppression withdrawal cannot currently be identified. (4) No data suggest that immunosuppression withdrawal decreases patient morbidity (ie, nephrotoxicity). (5) The minimization of immunosuppression instead of withdrawal may be adequate for improving patient outcomes.

Long-term results of liver transplantation

Liver transplantation (LT) is an established therapy associated with a dramatic improvement in patients life expectancy. With improved early-term management, current 10-year patient survival rates in many indications exceed 70%. Life-long immunosuppressive therapy may, however, be accompanied by considerable longterm toxicity: most importantly, renal dysfunction, cardiovascular disease, and cancer, which, in addition to recurrence of the primary liver disease, emerge as key contributors to late mortality. Chronic kidney disease cumulatively affects up to 28% of patients by ten years after LT. Various factors can contribute to renal impairment, but perioperative acute kidney injury, calcineurin inhibitor toxicity, hypertension, and diabetes are considered most important. LT patients demonstrate 3-fold risk for cardiovascular events, which seems to result mostly from an excess of traditional risk factors, mainly hypertension and diabetes. The cumulative cancer incidence reaches 16-42% by 20 years after LT, and cancer rates are 2- to 4-fold higher among LT patients than among matched controls. Highest rates are for nonmelanoma skin cancer (3- to 70-fold) and lymphoma (8- to 29-fold). The liver graft usually displays uncomplicated function in the long term. Most common causes for chronic graft dysfunction include disease recurrence and biliary problems. LT generally restores patients quality of life to a level comparable with that of the general population, with only minor deficits in some areas. Thus, long-term survival after LT is impressive, and despite these long-term complications, patients quality of life remains comparable with that of the general population.

Finding the right time for weaning off immunosuppression in solid organ transplant recipients

Solid organ transplantation (SOT) requires lifelong immunosuppression (IS) to prevent rejection and graft loss. The currently adopted immunosuppressive protocols are numerous and are based on the administration of at least two molecules with diverse mechanisms of action. Owing to the fact that the majority of immunosuppressants act non-selectively, the immune system is normally oversuppressed, and as a result is less able to both defend the host against infection and to control the spread of malignant cells. Consequently, long-term IS is burdened by chronic toxicity, which may be highly invalidating and may significantly influence patient's quality of life, compliance to treatment, overall success rate, and patient and graft survival. In an ideal scenario, SOT recipients should initially receive just enough IS to favor the onset of clinical operational tolerance (COT), a condition where the immune system of the host does not attack the graft in the absence of any immunosuppressant. COT has been documented after liver transplantation (LT) and renal transplantation (RT). First, COT was accidentally detected in patients who were nonadherent to treatment and who spontaneously decided to stop all IS without any medical guidance or surveillance. Later, it was described in recipients who required IS withdrawal following the occurrence of malignant diseases. Based on strikingly convincing experimental data, several tolerogenic protocols have recently been applied in patients but overall the results have been disappointing. The current literature demonstrates that COT can be safely achieved in stable LT recipients, with completely different strategies. Importantly, the onset of an episode of acute rejection during the attempt of IS withdrawal would not worsen the clinical outcome. On the contrary, COT remains a major challenge after RT because the onset of acute rejection will substantiate in graft loss. Currently, a major field of investigation aims to define markers of COT, which will allow the selection of individuals who are more prone to develop COT. Preliminary results in both RT and LT have just been announced; however, these markers will require validation in prospective studies.

Biomarker assessment of the immunomodulator effect of atorvastatin in stable renal transplant recipients and hypercholesterolemic patients

BACKGROUND

HMG-CoA reductase inhibitors (statins) have effects beyond lipid lowering, including immunomodulatory and anti-inflammatory properties. Statins are frequently combined with immunosuppressive agents in transplant recipients to modulate the hyperlipidemic side effects of the immunosuppressants. However, the role of statins in the immunosuppressive response that is achieved in individual patients remains to be assessed.

OBJECTIVE

The aim of this study was to evaluate the immunomodulatory effect of atorvastatin given alone and in combined treatment with tacrolimus and mycophenolate mofetil.

STUDY DESIGN

Two patient groups were studied: renal transplant recipients receiving tacrolimus and mycophenolate mofetil therapy, and hypercholesterolemic patients (the control group). Fasting blood samples were taken from participants before and 1 month after atorvastatin treatment was started to study a small battery of biomarkers that are able to reflect the range of the effects of immunosuppressive therapy and atorvastatin.

SETTING

All patients in the study were enrolled at the Hospital Clinic of Barcelona.

PATIENTS

All patients enrolled in the study were candidates for treatment with atorvastatin because of high cholesterol levels. One group consisted of 25 stable renal transplant recipients with low-density lipoprotein (LDL) cholesterol levels above 100 mg/dL after 3 months of therapeutic lifestyle changes, according to the guidelines of the National Kidney Foundation - Kidney Disease Outcomes Quality Initiative. The other group included 25 hypercholesterolemic patients with LDL cholesterol levels above target values for the patients' overall risk, as derived from the National Cholesterol Education Program Adult Treatment Panel III criteria.

INTERVENTION

Atorvastatin (Lipitor®) treatment was started at a fixed dose of 20 mg daily.

MAIN OUTCOME MEASURE

The studied biomarkers were lymphocyte proliferation, intracellular adenosine triphosphate (ATP) synthesis in CD4+ T cells, intralymphocytary cytokine expression (interleukin [IL]-2, interferon [IFN]-γ), soluble cytokine production (IL-2, IFN-γ, IL-10, IL-17, and transforming growth factor-β) and regulatory T (T(reg)) cells.

RESULTS

Atorvastatin proved to be an immunomodulatory agent, significantly decreasing lymphocyte proliferation by 15% (p = 0.001), increasing ATP levels by 16% (p = 0.0004), and showing a trend toward increasing T(reg) cells in hypercholesterolemic patients (p = 0.09). In the renal transplant recipients, atorvastatin therapy did not modify any of the biomarkers of immunosuppression that were studied.

CONCLUSION

Atorvastatin showed immunoregulatory effects on T cells in hypercholesterolemic patients. These effects were absent in renal transplant recipients, suggesting that the beneficial effects of atorvastatin in this patient group do not relate to immunoregulation. Therefore, statin treatment cannot be considered as a means to reduce the dose of immunosuppressive agents.

Biomarker assessment of the immunomodulator effect of atorvastatin in stable renal transplant recipients and hypercholesterolemic patients

BACKGROUND

HMG-CoA reductase inhibitors (statins) have effects beyond lipid lowering, including immunomodulatory and anti-inflammatory properties. Statins are frequently combined with immunosuppressive agents in transplant recipients to modulate the hyperlipidemic side effects of the immunosuppressants. However, the role of statins in the immunosuppressive response that is achieved in individual patients remains to be assessed.

OBJECTIVE

The aim of this study was to evaluate the immunomodulatory effect of atorvastatin given alone and in combined treatment with tacrolimus and mycophenolate mofetil.

STUDY DESIGN

Two patient groups were studied: renal transplant recipients receiving tacrolimus and mycophenolate mofetil therapy, and hypercholesterolemic patients (the control group). Fasting blood samples were taken from participants before and 1 month after atorvastatin treatment was started to study a small battery of biomarkers that are able to reflect the range of the effects of immunosuppressive therapy and atorvastatin.

SETTING

All patients in the study were enrolled at the Hospital Clinic of Barcelona.

PATIENTS

All patients enrolled in the study were candidates for treatment with atorvastatin because of high cholesterol levels. One group consisted of 25 stable renal transplant recipients with low-density lipoprotein (LDL) cholesterol levels above 100 mg/dL after 3 months of therapeutic lifestyle changes, according to the guidelines of the National Kidney Foundation - Kidney Disease Outcomes Quality Initiative. The other group included 25 hypercholesterolemic patients with LDL cholesterol levels above target values for the patients' overall risk, as derived from the National Cholesterol Education Program Adult Treatment Panel III criteria.

INTERVENTION

Atorvastatin (Lipitor®) treatment was started at a fixed dose of 20 mg daily.

MAIN OUTCOME MEASURE

The studied biomarkers were lymphocyte proliferation, intracellular adenosine triphosphate (ATP) synthesis in CD4+ T cells, intralymphocytary cytokine expression (interleukin [IL]-2, interferon [IFN]-γ), soluble cytokine production (IL-2, IFN-γ, IL-10, IL-17, and transforming growth factor-β) and regulatory T (T(reg)) cells.

RESULTS

Atorvastatin proved to be an immunomodulatory agent, significantly decreasing lymphocyte proliferation by 15% (p = 0.001), increasing ATP levels by 16% (p = 0.0004), and showing a trend toward increasing T(reg) cells in hypercholesterolemic patients (p = 0.09). In the renal transplant recipients, atorvastatin therapy did not modify any of the biomarkers of immunosuppression that were studied.

CONCLUSION

Atorvastatin showed immunoregulatory effects on T cells in hypercholesterolemic patients. These effects were absent in renal transplant recipients, suggesting that the beneficial effects of atorvastatin in this patient group do not relate to immunoregulation. Therefore, statin treatment cannot be considered as a means to reduce the dose of immunosuppressive agents.

Immunosuppressants: what's new?

PURPOSE OF REVIEW

Advances in surgical techniques and combinations of conventional immunosuppressants have made paediatric liver transplantation the success story it is today. However, the increasing numbers of survivors reaching adulthood highlight important issues of long-term quality of life and drug induced complications. The aim of this review is to describe the trends and advances in immunosuppression for paediatric liver transplantation over the last 12 months.

RECENT DEVELOPMENTS

As our knowledge of the immune cell populations and intracellular mechanisms involved in alloreactivity improves, induction immunosuppression has emerged as a powerful therapeutic manoeuvre to counter the initial alloimmune response. Many centres have adopted a more focused use of biological agents at induction to improve immunosuppression in the critical peritransplant period and to reduce the level of subsequent maintenance requirements. Corticosteroid avoidance and calcineurin inhibitors minimization trials have obtained encouraging results. New immunosuppressive strategies have evolved towards the goal of inducing operational tolerance, and paediatric liver transplant recipients seem to be a particularly promising target. New strategies are being developed also to improve quality of life and reduce nonadherence in adolescents and young adults who underwent liver transplantation. New drugs target B-cell and complement driven rejection and new monoclonal antibodies and small molecules are under trial to inhibit specific signals in the immune response.

SUMMARY

We review current trends of immunosuppressive protocols in paediatric liver transplantation, focusing on induction agents, corticosteroid avoidance and calcineurin inhibitor sparing protocols, protocols for adult transition and new drugs currently under development.

Clinical operational tolerance after renal transplantation: current status and future challenges

In solid organ transplantation, the achievement of an immunosuppression (IS)-free state [also referred to as clinical operational tolerance (COT)] represents the ultimate goal. Although COT is feasible and safe in selected cases after liver transplantation, it is an exceptional finding after other types of solid organ transplantation. In the field of renal transplantation (RT), approximately 100 cases of COT have been reported to date, mainly in patients who were not compliant with their immunosuppressive regimens or in individuals who had previously received a bone marrow transplant for hematological disorders. On the basis of promising results obtained in animal models, several tolerogenic protocols have been attempted in humans, but most have failed to achieve robust and stable COT after RT. Molecule-based regimens have been largely ineffective, whereas cell-based regimens have provided some encouraging results. In these latter regimens, apart from standard IS, patients usually receive perioperative infusion of donor bone marrow-derived stem cells, which are able to interact with the immune cells of the host and mitigate their response to engraftment. Unfortunately, most renal transplant patients who developed acute rejection-occurring either during the weaning protocol or after complete withdrawal of IS-eventually lost their grafts. Currently, the immune monitoring necessary for predicting the presence and persistence of donor-specific unresponsiveness is not available. Overall, the present review will provide a conceptual framework for COT and conclude that stable and robust COT after RT remains an elusive goal and that the different strategies attempted to date are not yet reproducibly safe or effective.

Safety and efficacy of steroid-free immunosuppression with tacrolimus and daclizumab in liver transplant recipients: 6-year follow-up in a single center

BACKGROUND

Avoidance of steroid therapy after solid-organ transplantation has become a major challenge. Corticosteroid (CS)-free maintenance immunosuppression not only eliminates the well-known adverse effects but also may improve long-term outcome.

OBJECTIVE

To investigate whether a CS-free regimen of tacrolimus (Tac) in combination with daclizumab (Dac) induction therapy provides adequate coverage after orthotopic liver transplantation.

PATIENTS AND METHODS

This 6-year, single-center, retrospective study included 25 liver transplant recipients randomized to a Tac/CS regimen (n = 18) vs a Tac/Dac regimen (n = 7) according to the protocol of the MASTER (Monoclonal Antibodies vs STERoids) Study.

RESULTS

No significant difference was observed in patient and graft survival between treatment arms: 94.4% in the Tac/CS group vs 71.4% in the Tac/Dac group. The incidence of biopsy-proved acute rejection episodes was 23.5% in the Tac/CS group vs 14.3% in the Tac/Dac group (P = NS). Total duration of hospitalization did not differ significantly between groups: 46.5 days in the Tac/CS group vs 73.9 days in the Tac/Dac group. Liver function as estimated using serum alanine aminotransferase and aspartate aminotransferase activity and bilirubin concentration, was not significantly different between the groups during 5 years posttransplantation. However, after 6 years, alanine aminotransferase activity was significantly greater in the Tac/Dac group compared with the Tac/CS group.

CONCLUSIONS

A CS-free regimen of Tac/Dac is as effective as Tac/Cs in achieving good patient and graft survival. However, no substantial benefits insofar as the safety of Tac/Dac therapy were evident during long-term follow-up.

Ab initio calcineurin inhibitor-based monotherapy immunosuppression after liver transplantation reduces the risk for Pneumocystis jirovecii pneumonia

At the Tor Vergata University of Rome, ab initio calcineurin inhibitor-based monotherapy immunosuppression (IS) is the standard of treatment after liver transplantation (LT). As the net state of IS determines the onset of Pneumocystis jirovecii pneumonia (PCP), we hypothesized that, in the presence of weak impairment of the immune function, as determined by the above-mentioned IS, the host is not overexposed to the risk for PCP and consequently the specific anti-PCP prophylaxis is unnecessary. In a single-cohort descriptive study, we retrospectively investigated the incidence of PCP in 203 LT patients who did not receive anti-PCP prophylaxis because they were under monotherapy IS. The primary endpoint of the study was the incidence of PCP during the first 12 months following LT; secondary endpoints were the incidence of acute rejection requiring additional IS and of CMV infection. No cases of PCP were recorded. The incidence of CMV and acute rejection was 3.9% and 0.9%, respectively. Our data suggest that monotherapy IS after LT may nullify the risk for PCP even in the absence of any specific prophylaxis.

Fatty liver and liver transplantation

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis are common complications of overnutrition and obesity. In the setting of worsening epidemics of obesity in developed and developing countries, the global prevalence and impact of NAFLD seems likely to increase. The large number of patients at risk will translate into major challenges for the liver transplant community, affecting donors and recipients. The comorbidities and hepatic effects of obesity and NAFLD present important new challenges in the management of donors and recipients. This article addresses some of these challenges.