Pediatric liver transplantation with daclizumab induction

Meta-analysis of two studies in the presence of heterogeneity with applications in rare diseases

Random-effects meta-analyses are used to combine evidence of treatment effects from multiple studies. Since treatment effects may vary across trials due to differences in study characteristics, heterogeneity in treatment effects between studies must be accounted for to achieve valid inference. The standard model for random-effects meta-analysis assumes approximately normal effect estimates and a normal random-effects model. However, standard methods based on this model ignore the uncertainty in estimating the between-trial heterogeneity. In the special setting of only two studies and in the presence of heterogeneity, we investigate here alternatives such as the Hartung-Knapp-Sidik-Jonkman method (HKSJ), the modified Knapp-Hartung method (mKH, a variation of the HKSJ method) and Bayesian random-effects meta-analyses with priors covering plausible heterogeneity values; R code to reproduce the examples is presented in an appendix. The properties of these methods are assessed by applying them to five examples from various rare diseases and by a simulation study. Whereas the standard method based on normal quantiles has poor coverage, the HKSJ and mKH generally lead to very long, and therefore inconclusive, confidence intervals. The Bayesian intervals on the whole show satisfying properties and offer a reasonable compromise between these two extremes.

Meta-analysis of few small studies in orphan diseases

Meta-analyses in orphan diseases and small populations generally face particular problems, including small numbers of studies, small study sizes and heterogeneity of results. However, the heterogeneity is difficult to estimate if only very few studies are included. Motivated by a systematic review in immunosuppression following liver transplantation in children, we investigate the properties of a range of commonly used frequentist and Bayesian procedures in simulation studies. Furthermore, the consequences for interval estimation of the common treatment effect in random-effects meta-analysis are assessed. The Bayesian credibility intervals using weakly informative priors for the between-trial heterogeneity exhibited coverage probabilities in excess of the nominal level for a range of scenarios considered. However, they tended to be shorter than those obtained by the Knapp-Hartung method, which were also conservative. In contrast, methods based on normal quantiles exhibited coverages well below the nominal levels in many scenarios. With very few studies, the performance of the Bayesian credibility intervals is of course sensitive to the specification of the prior for the between-trial heterogeneity. In conclusion, the use of weakly informative priors as exemplified by half-normal priors (with a scale of 0.5 or 1.0) for log odds ratios is recommended for applications in rare diseases. © 2016 The Authors. Research Synthesis Methods published by John Wiley & Sons Ltd.

Current developments in pediatric liver transplantation

In 1953, the pioneer of human orthotopic liver transplantation (LT), Thomas E Starzl, was the first to attempt an orthotopic liver transplant into a 3 years old patient suffering from biliary atresia. Thus, the first LT in humans was attempted in a disease, which, up until today, remains the main indication for pediatric LT (pLT). During the last sixty years, refinements in diagnostics and surgical technique, the introduction of new immunosuppressive medications and improvements in perioperative pediatric care have established LT as routine procedure for childhood acute and chronic liver failure as well as inherited liver diseases. In contrast to adult recipients, pLT differs greatly in indications for LT, allocation practice, surgical technique, immunosuppression and post-operative life-long aftercare. Many aspects are focus of ongoing preclinical and clinical research. The present review gives an overview of current developments and the clinical outcome of pLT, with a focus on alternatives to full-size deceased-donor organ transplantation.

Interleukin-2 receptor antagonists for pediatric liver transplant recipients: a systematic review and meta-analysis of controlled studies

IL-2RA are frequently used as induction therapy in liver transplant recipients to decrease the risk of AR while allowing the reduction of concomitant immunosuppression. The exact association with the use of IL-2RA, however, is uncertain. We performed a systematic literature search for relevant studies. Random effects models were used to assess the incidence of AR, steroid-resistant rejection, graft loss, patient death, and adverse drug reaction, with or without IL-2RA. Six studies (two randomized and four non-randomized) met the eligibility criteria. Acute rejection at six months or later favored the use of IL-2RA significantly (RR 0.38; 95% CI 0.22-0.66, p = 0.0005). Although not statistically significant, IL-2RA showed a substantial reduction of the risk of steroid-resistant rejection (RR 0.32; CI 0.19-1.03, p = 0.0594). Graft loss and patient death showed a reductive tendency through the use of IL-2RA. The use of IL-2RA is safe and is associated with a statistically significantly lower incidence of AR after transplantation and substantial reduction of steroid-resistant rejection, graft loss, and patient death.

Risk of serious opportunistic infections after solid organ transplantation: interleukin-2 receptor antagonists versus polyclonal antibodies. A meta-analysis

BACKGROUND

We aimed to evaluate and quantify the risk of serious opportunistic infections after induction with polyclonal antibodies versus IL-2 receptor antagonists (IL-2RAs) in randomized clinical trials.

METHODS

PRISMA guidelines were followed and random-effects models were performed.

RESULTS

70 randomized clinical trials (10,106 patients) were selected: 36 polyclonal antibodies (n = 3377), and 34 IL-2RAs (n = 6729). Compared to controls, polyclonal antibodies showed higher risk of serious opportunistic infections (OR: 1.93, 95% CI: 1.34-2.80; p < 0.0001); IL-2RAs were associated with lower risk of serious opportunistic infections (OR: 0.80, 95% CI: 0.68-0.94; p = 0.009). Polyclonal antibodies were associated with higher risk of bacterial (OR: 1.58, 95% CI: 1.00-2.50; p = 0.049) and viral infections (OR: 2.37, 95% CI: 1.60-3.49; p < 0.0001), while IL-2RAs were associated with lower risk of cytomegalovirus (CMV) disease (OR: 0.73, 95% CI: 0.56-0.97; p = 0.032). Adjusted indirect comparison: compared to polyclonal antibodies, IL-2RAs were associated with lower risk of serious opportunistic infections (OR: 0.41, 95% CI: 0.34-0.49; p < 0.0001), bacterial infections (OR: 0.51, 95% CI: 0.39-0.67; p < 0.0001) and CMV disease (OR: 0.58, 95% CI: 0.34-0.98; p = 0.043). Results remained consistent across allografts.

CONCLUSION

The risk of serious opportunistic infections, bacterial infections and CMV disease were all significantly decreased with IL-2RAs compared to polyclonal antibodies.

Prevalence of renal dysfunction in tacrolimus-treated pediatric transplant recipients: a systematic review

Renal dysfunction after non-renal transplantation in adult tacrolimus-treated transplant patients is well documented. Little is known about its prevalence in children. Age-related changes in both disposition and effect of tacrolimus as well as renal function may preclude extrapolation of adult data to children. To systematically review the literature on renal dysfunction in non-renal pediatric transplant recipients treated with tacrolimus. PubMed/Medline, Embase, and Google were searched from their inception until April 19, 2012, with the search terms "tacrolimus," "renal function," "transplantation," and "children." Eighteen of 385 retrieved papers were considered relevant. Twelve dealt with liver, four with heart transplant, one with heart and lung transplant, and one with intestinal recipients. Reported prevalences of mild and severe chronic kidney disease ranged from 0% to 39% and 0% to 71.4%, respectively, for liver, and from 22.7% to 40% and 6.8% to 46%, respectively, for heart and/or lung transplant recipients. Ranges remained wide after adjusting for follow-up time and disease severity. Possible explanations are inclusion bias and definitions used for renal dysfunction. A considerable proportion of pediatric non-renal transplant patients who receive tacrolimus-based immunosuppression, appear to suffer from chronic kidney disease. This conclusion warrants further research into the real risk, its risk factors, and individualization of immunosuppressant therapy.

The kidney in pediatric liver transplantation: an updated perspective

CKD continues to detract from the success of improved survival in pediatric liver transplantation, and its presence is likely under recognized. Here we review the literature regarding the prevalence, etiology, and management of renal dysfunction in pediatric liver transplant recipients. Long-term studies suggest the prevalence of CKD to be 25-38% by 5-10 yr post-transplant. While important, sole use of serum creatinine overestimates renal function in this population. Screening for and treatment of persistent proteinuria and hypertension as well as minimization of nephrotoxic insults are the mainstays to delay or prevent CKD progression. Office-based blood pressure measures are less sensitive than ABPM, which is specifically recommended by the American Heart Association for its ability to diagnose masked hypertension in pediatric liver transplant recipients. Long-term risk of CKD is predominantly secondary to CNI toxicity. CNI minimization protocols have shown promise in slowing progression of CKD while maintaining graft function, but large-scale randomized control trials with long-term follow-up are needed.

Monitoring of nonsteroidal immunosuppressive drugs in patients with lung disease and lung transplant recipients: American College of Chest Physicians evidence-based clinical practice guidelines

OBJECTIVES

Immunosuppressive pharmacologic agents prescribed to patients with diffuse interstitial and inflammatory lung disease and lung transplant recipients are associated with potential risks for adverse reactions. Strategies for minimizing such risks include administering these drugs according to established, safe protocols; monitoring to detect manifestations of toxicity; and patient education. Hence, an evidence-based guideline for physicians can improve safety and optimize the likelihood of a successful outcome. To maximize the likelihood that these agents will be used safely, the American College of Chest Physicians established a committee to examine the clinical evidence for the administration and monitoring of immunosuppressive drugs (with the exception of corticosteroids) to identify associated toxicities associated with each drug and appropriate protocols for monitoring these agents.

METHODS

Committee members developed and refined a series of questions about toxicities of immunosuppressives and current approaches to administration and monitoring. A systematic review was carried out by the American College of Chest Physicians. Committee members were supplied with this information and created this evidence-based guideline.

CONCLUSIONS

It is hoped that these guidelines will improve patient safety when immunosuppressive drugs are given to lung transplant recipients and to patients with diffuse interstitial lung disease.

Current status of immunosuppressive agents for solid organ transplantation in children

Immunosuppression after organ transplantation is complex and ever evolving. Over the past two decades, newer immunosuppressive agents have been introduced with an aim to provide better patient and graft survival. Improved therapeutic strategies have been developed offering the option to use combinations of drugs with non-overlapping toxicities. There are, however, only a few clinical studies with robust data to rationalize the use of these agents in children. This review will discuss the newer immunosuppressive agents used for solid organ transplant, their current status in post-transplant management and prevention of allograft rejection.

A therapeutic exploratory study to determine the efficacy and safety of calcineurin-inhibitor-free de-novo immunosuppression after liver transplantation: CILT

Background

Immunosuppression with calcineurin inhibitors (CNI) increases the risk of renal dysfunction after orthotopic liver transplantation (OLT). Controlled trials have shown improvement of renal function in patients that received delayed and/or reduced-dose CNI after OLT. Delaying immunosuppression with CNI in combination with induction therapy does not increase the risk of acute rejection but reduces the incidence of acute renal dysfunction. Based on this clinical data this study protocol was designed to assess the efficacy and safety of calcineurin-inhibitor-free de-novo immunosuppression after liver transplantation.

Methods/Design

A prospective therapeutic exploratory, non-placebo controlled, two stage monocenter trial in a total of 29 liver transplant patients was designed to assess the safety and efficacy of de-novo CNI-free immunosuppression with basiliximab, mycophenolate sodium, prednisolone and everolimus. The primary endpoint is the rate of steroid resistant rejections. Secondary endpoints are the incidence of acute rejection, kidney function (assessed by incidence and duration of renal replacement therapy, incidence of chronic renal failure, and measurement glomerular filtration rate), liver allograft function (assessed by measurement of AST, ALT, total bilirubin, AP, GGT), treatment failure, (i. e., re-introduction of CNI), incidence of adverse events, and mortality up to one year after OLT.

Discussion

This prospective, two-stage, single-group pilot study represents an intermediate element of the research chain. If the data of the phase II study corroborates safety of de-novo CNI-free immunosuppressive regimen this should be confirmed in a randomized, prospective, controlled double-blinded clinical trial. The exploratory data from this trial may then also facilitate the design (e. g. sample size calculation) of this phase III trial.

Trial registration number

NCT00890253 (clinicaltrials.gov)

Pediatric liver transplantation for acute liver failure at a single center: a 10-yr experience

Children transplanted for ALF urgently require an optimal graft and have lower post-transplant survival compared with children transplanted for chronic liver disease. Over 10 yr, 33 consecutive children transplanted for ALF were followed. Demographics, encephalopathy, intubation, dialysis, laboratory values, graft type ABOI, XL (GRWR > 5%), DDSLT, LDLT and WLT were evaluated. Complications and survival were determined. ALF accounted for 33/201 (16.4%) of transplants during this period. Twelve of 33 received ABOI, five XL grafts, 18 DDSLT, and three LDLT. Waiting time pretransplant was 2.1 days. One- and three-yr patient survival in the ALF group was 93.4% and 88.9%, and graft survivals were 86.4% and 77.7%. Median follow-up was 1452 days. ABOI one- and three yr patient and graft survival in the ALF was 91.6% and 78.6%. No difference in graft or patient survival was noted in the ALF and chronic liver disease group or the ABOI and the ABO compatible group. A combination of ABO incompatible donor livers, XL grafts, DDSLT, LDLT and WLT led to a short wait time and subsequent graft and patient survival comparable to patients with non-acute disease.

Calcineurin inhibitor minimization in pediatric liver allograft recipients

The use of CNI in pediatric LTx has dramatically improved the outcome for children with end-stage liver disease by significantly reducing the rate of acute and chronic rejection. Long-term concerns about CNI-induced nephrotoxicity and other adverse effects remain an issue, particularly as the emphasis moves from short-term survival to long-term quality of life. This review summarizes lessons learnt from pediatric and adult solid organ transplantation in minimizing CNI use in immunosuppression protocols in children following LTx. There are three models for CNI minimization: dose reduction, withdrawal or avoidance, supplemented by the use of IL-2 receptor blocking antibodies in the peri-transplant period, and early transition to alternate drugs such as MMF or SRL. Prospective studies evaluating reduction or withdrawal protocols in adult and pediatric LTx indicate that rejection rates are comparable with traditional CNI-based immunosuppression and that two and five yr patient and graft survival are similar, with recovery in renal function. There are few studies evaluating complete avoidance of CNI, apart from that in renal transplantation, although the benefits of long-term reduction in cardiovascular, metabolic, and possibly neoplastic side effects may justify this approach. It is not clear yet how CNI minimization will affect the development of tolerance but experimental and preliminary clinical studies indicate that CNI and steroid avoidance or minimization in the peri-operative period may favor the development of long-term graft tolerance. In summary, CNI minimization may be safe and effective in the short term but large-scale pediatric randomized studies are required to evaluate the long-term efficacy of these regimes in the development of chronic rejection, PTLD, and graft tolerance.

Pediatric liver transplantation

In previous decades, pediatric liver transplantation has become a state-of-the-art operation with excellent success and limited mortality. Graft and patient survival have continued to improve as a result of improvements in medical, surgical and anesthetic management, organ availability, immunosuppression, and identification and treatment of postoperative complications. The utilization of split-liver grafts and living-related donors has provided more organs for pediatric patients. Newer immunosuppression regimens, including induction therapy, have had a significant impact on graft and patient survival. Future developments of pediatric liver transplantation will deal with long-term follow-up, with prevention of immunosuppression-related complications and promotion of as normal growth as possible. This review describes the state-of-the-art in pediatric liver transplantation.

Calcineurin inhibitor sparing in paediatric solid organ transplantation : managing the efficacy/toxicity conundrum

Despite their efficacy, the calcineurin inhibitors (CNIs) ciclosporin and tacrolimus carry a risk of debilitating adverse effects, especially nephrotoxicity, that affect the long-term outcome and survival of children who are given organ transplants. Simple reduction in dosage of CNI has little or no long-term benefit on their adverse effects, and complete withdrawal without threatening graft outcome may only be possible after liver transplantation. Until the last decade, the only option was to increase corticosteroid and/or azathioprine doses, which imposed additional long-term hazards. Considered here are the emerging generation of new agents offering an opportunity for improving long-term graft survival, minimizing CNI-related adverse events and ensuring patient well-being.A holistic, multifaceted strategy may need to be considered - initial selection and optimized use and monitoring of immunosuppressant regimens, early recognition of indicators of patient and graft dysfunction, and, where applicable, early introduction of CNI-sparing regimens facilitating CNI withdrawal. The evidence reviewed here supports these approaches but remains far from definitive in paediatric solid organ transplantation. Because de novo immunosuppression uses CNI in more than 93% of patients, reduction of CNI-related adverse effects has focused on CNI sparing or withdrawal.A recurring theme where sirolimus and mycophenolate mofetil have been used for this purpose is the importance of their early introduction to limit CNI damage and provide long-term benefit: for example, long-term renal function critically reflects that at 1 year post-transplant. While mycophenolic acid shows advantages over sirolimus in preserving renal function because the latter is associated with proteinuria, sirolimus appears the more potent immunosuppressant but also impairs early wound healing. The use of CNI-free immunosuppressant regimens with depleting or non-depleting antibodies plus sirolimus and mycophenolic acid needs much wider investigation to achieve acceptable rejection rates and conserve renal function. The adverse effects of the alternative immunosuppressants, particularly the dyslipidaemia associated with sirolimus, needs to be minimized to avoid replacing one set of adverse effects (from CNIs) with another. While we can only conjecture that judicious combinations with the second generation of novel immunosuppressants currently in development will provide these solutions, a rationale of low-dose therapy with multiple immunosuppressants acting by complementary mechanisms seems to hold the promise for efficacy with minimal toxicity until the vision of tolerance achieves reality.

Safety and pharmacokinetics of daclizumab in pediatric renal transplant recipients

This study examined the safety and pharmacokinetics/pharmacodynamics of daclizumab in combination with mycophenolate mofetil (or azathioprine), corticosteroids, and cyclosporine or tacrolimus, in 61 pediatric renal allograft recipients in three age groups: less than or equal to five yr (n = 18), 6-12 yr (n = 18), and 13-17 yr (n = 25). The dosing regimen was daclizumab 1.0 mg/kg before transplantation, followed by four biweekly doses. The pharmacokinetics of daclizumab were described using NONMEM software. Median (range) estimated trough daclizumab levels achieved on day 56 (before dose 5) were 3.88 microg/mL (2.48-8.78), 4.54 microg/mL (1.79-18.7), and 4.94 microg/mL (0.05-10.6) in the less than or equal to five yr (n = 15), 6-12 yr (n = 17), and 13-17 yr (n = 22) age groups, respectively. Steady-state median (range) daclizumab exposures were 2040 mg x h/mL (1585-3778), 2757 mg x h/mL (1873-3494) and 3297 mg x h/mL (1705-6453), respectively. Saturation of the IL-2R occurred rapidly and was maintained for greater than or equal to three months after transplantation. Daclizumab was generally well-tolerated with no acute allergic or anaphylactic reactions, deaths or malignancies during the study. The proportion of patients who developed acute rejection at six and 12 months was 8.5% and 16.7%, respectively. This study shows that adding daclizumab at 1 mg/kg to standard immunosuppressive therapy provides safe and effective IL-2R blockade.

Risk factors for rejection and infection in pediatric liver transplantation

Rejection and infection are important adverse events after pediatric liver transplantation, not previously subject to concurrent risk analysis. Of 2291 children (<18 years), rejection occurred at least once in 46%, serious bacterial/fungal or viral infections in 52%. Infection caused more deaths than rejection (5.5% vs. 0.6% of patients, p < 0.001). Early rejection (<6 month) did not contribute to mortality or graft failure. Recurrent/chronic rejection was a risk in graft failure, but led to retransplant in only 1.6% of first grafts. Multivariate predictors of bacterial/fungal infection included recipient age (highest in infants), race, donor organ variants, bilirubin, anhepatic time, cyclosporin (vs. tacrolimus) and era of transplant (before 2002 vs. after 2002); serious viral infection predictors included donor organ variants, rejection, Epstein-Barr Virus (EBV) naivety and era; for rejection, predictors included age (lowest in infants), primary diagnosis, donor-recipient blood type mismatch, the use of cyclosporin (vs. tacrolimus), no induction and era. In pediatric liver transplantation, infection risk far exceeds that of rejection, which causes limited harm to the patient or graft, particularly in infants. Aggressive infection control, attention to modifiable factors such as pretransplant nutrition and donor organ options and rigorous age-specific review of the risk/benefit of choice and intensity of immunosuppressive regimes is warranted.

Daclizumab

Daclizumab is a humanized monoclonal antibody which binds to the IL-2 receptor on activated lymphocytes and blocks the production of IL-2. Its use is well established in solid organ transplantation as induction therapy, especially in high-risk patients where reduction or delayed dose of standard immunosuppression would be beneficial. It has been used effectively in both 2-dose and 5-dose regimens in conjunction with other standard immunosuppressive agents. The incidence of acute rejection appears reduced without increasing the rates of infection or post-transplant lympho-proliferative disorders. The agent is generally well tolerated in adults and children and there is no need for additional monitoring. Daclizumab has also been used outside the transplant arena in a variety of immune-mediated diseases with limited success.

Medical and surgical treatment of neonatal hemochromatosis: single center experience

NH is a rare disorder of iron storage in newborns resulting in rapid liver failure. Outcomes are dismal with 20-30% survival. We report our experience in eight children with NH. Assessment of liver function included admission PT and serum levels of FV and FVII. Medical treatment (antioxidant cocktail) was started in all patients, with chelation therapy in six. Of these six, three survived with medical treatment alone. The other three underwent liver transplant. One died 158 days after transplant to sepsis: two are well more than five yr after transplant. The two neonates who did not receive chelation therapy, died to multi-organ failure and sepsis. In summary, five children (62.5%) survived long-term. In the three transplanted, one- and five-yr-survival was 66%. Older children with compromised synthetic liver function (FVII levels < or = 15%) required liver replacement for survival. Early referral to a tertiary care center is essential to increase survival of these children with a rare and otherwise fatal disease. Single center experience of children with NH is here presented. Potentials for survival improvement with of medical and surgical treatment are examined.

The challenge of renal function in heart transplant children

Renal dysfunction may occur after pediatric heart transplantation and impacts on long-term prognosis. This study aims to review the incidence and mechanisms of chronic nephropathy following heart transplantation, and suggest therapeutic directions. The proportion of pediatric heart-transplant recipients with impaired renal function varies from 22 to 57%, and end-stage renal failure from 3 to 10%, depending on the method used for estimating the glomerular filtration rate. The pathophysiology of renal dysfunction is in part due to calcineurin inhibitor-induced renal vasoconstriction, through activation of the intrarenal renin-angiotensin system, TGF-beta1 upregulation and TGF-beta1 gene polymorphisms. Overproduction of angiotensin II, associated with angiotensin-converting-enzyme genotype, might be associated with poor prognosis and pharmacological factor gene polymorphisms, and may contribute to variation of calcineurine inhibitor exposure in the kidney. Strategies to prevent renal dysfunction include reducing calcineurine inhibitor exposure or delaying calcineurine inhibitor administration from the early post-transplant period. Calcium channel blockers and angiotensin-converting-enzyme inhibitors, blockade of angiotensin II, or anti-TGF-beta1 antibodies might limit nephrotoxicity. No accurate marker can predict the potential of renal lesions to develop. Lowering calcineurine inhibitors levels with immunosuppressive agents that are either less nephrotoxic or non-nephrotoxic should be formally studied. Of high interest is the impact of genetic polymorphism on the development of renal dysfunction.

Liver transplantation in children

Liver transplantation (LT) is now a standard treatment for children with end-stage liver disease with excellent 1- and 5-year survival. This has been achieved through improvement of surgical techniques and anti-rejection treatment and management. The donor pool for children has been extended by the use of cut-down, split, living-related and, recently, non-heart-beating donor and isolated hepatocyte transplantation. Though the majority of transplanted children enjoy an excellent quality of life, there remain a high number of possible complications, including short-term primary non-function, vascular and biliary problems, bowel perforation, severe rejection, infection, hypertension and long-term renal impairment, chronic rejection, de novo autoimmunity, lymphoproliferative disease and cancer, most of which are related to anti-rejection drug toxicity. Hence, the focus of research for paediatric LT should be induction of tolerance, avoiding long-term immunosuppression and its toxicity.

Immunosuppression in pediatric solid organ transplantation: opportunities, risks, and management

The pediatric transplant community stands at a time of unprecedented choice of immunosuppressive agents - and with a legacy of morbidity from those agents used in the previous two decades. This review considers the clinical utility and side-effect profiles of immunosuppressants used widely in current practice (e.g., glucocorticoids, azathioprine, ciclosporin, tacrolimus, mycophenolate, and sirolimus) and those agents which are in increasing use or in evaluation (e.g., IL-2 receptor antibodies, everolimus, FTY720, LEA29Y, and deoxyspergualin). Further consideration is given to the wider drug interactions likely during the use of new immunosuppressant regimens and to our growing awareness of the influences of genetic heterogeneity on drug efficacy and handling. Finally, we consider the new demands being placed on the use of drug monitoring to regulate dosage of this new repertoire of immunosuppressants.

Immunosuppression in pediatric solid organ transplantation

This report reviews the immunosuppressive regimens that are used in pediatric transplantation. There are predominant themes developing in the field involving the minimization of the total exposure of immunosuppression through limiting the number of agents and newer pharmacokinetic modeling. Calcineurin inhibitors are the foundation of most immunosuppressive regimens. However, there are new pharmacologic monitoring techniques to reduce the potential for long-term side effects of this class of agents. Although tacrolimus remains one of the mainstays of current protocols, there are strides being made to reduce the patient's long-term exposure to it with transitioning to sirolimus. Corticosteroids are still used predominantly, but there is growing evidence of successful steroid-sparing protocols that are as effective and avoid the chronic morbidity of steroids. Antibody induction therapy remains a standard with clearer evidence of the efficacy of IL-2 receptor antagonists. There is preliminary clinical evidence that polyclonal antibody therapy is efficacious in pediatric transplantation. Future studies will determine the best way to assess the functional immune status of a pediatric transplant recipient to maintain the fine balance and avoid the complications of either excessive or inadequate immunosuppression.

Randomized trial of basiliximab induction versus steroid therapy in pediatric liver allograft recipients under tacrolimus immunosuppression

Avoidance of corticosteroids could be beneficial after pediatric liver transplantation (LTx). To test this hypothesis, we performed a randomized prospective study to compare immunosuppression with tacrolimus (TAC) and steroids versus TAC and basiliximab (BAS) after pediatric LTx. Seventy-two patients were recruited, 36 receiving TAC and steroids and 36 TAC and BAS. The primary endpoint was the occurrence of the first rejection episode. Secondary endpoints were the cumulative incidence and severity of rejection, patient and graft survival, and incidence of adverse events. Overall 1-year patient and graft survival rates were 91.4% and 85.5% in the steroid group, and 88.6% and 80% in the BAS group (p = NS). Patients free from rejection were 87.7% in the BAS group and 67.7% in the steroid group (p = 0.036). The use of BAS was associated with a 63.6% reduction in incidence of acute rejection episodes. Overall incidence of infection was 72.3% in the steroid group and 50% in the BAS group (p = 0.035). We conclude that the combination of TAC with BAS is an alternative to TAC and steroid immunosuppression in pediatric LTx, which allows for a significant reduction in the incidence of acute rejection and infectious complications.

Liver transplant in a four-month-old child with biliary atresia, unilateral pulmonary agenesis, and diaphragmatic hernia: first case report

Bilateral pulmonary agenesis (PA) is a rare embryological defect incompatible with life. Unilateral PA has a wide range of clinical presentations: its prognosis depends on the presence and severity of other associated anomalies. Fetal biliary atresia has been associated with a number of congenital anomalies, but the etiology is still not understood. An unusual case of a child with right PA, right diaphragmatic hernia, and delayed diagnosed biliary atresia leading to liver failure is presented herein. At the age of 4 months the patient was referred to the Transplant Department at Children Healthcare of Atlanta at Egleston with cholestasis and failure to thrive. With a rapidly progressive liver insufficiency, this child was evaluated for liver transplantation. In the absence of any respiratory symptom, the patient received a deceased donor size-matched left lateral segment liver transplant, which covered the diaphragmatic defect, with no further repair required. Twenty-seven months post-transplant, the patient has good graft function, a normal Z-score and is thriving. In spite of the increased physiological and surgical challenges (absence of right lung tissue, hemi-diaphragm, and ectopic position of the liver in the right chest), liver transplantation was performed with positive outcome in this high-risk child. Whether PA, may have developmentally contributed to expression of biliary atresia will need further investigation.

Anti-interleukin 2 receptor antibodies and mycophenolate mofetil for treatment of steroid-resistant rejection in adult liver transplantation

BACKGROUND

Steroid-resistant rejection (SRR) results in significant morbidity and mortality from the adverse effects of rescue therapy and in graft loss from chronic rejection. In our knowledge, the efficacy and safety of anti-interleukin (IL) 2r antibodies (daclizumab and basiliximab) for the treatment of SRR in adult liver transplantation has not previously been evaluated.

METHODS

Twenty-five patients received either daclizumab or basiliximab as rescue therapy for SRR. Outcome and biochemical parameters were recorded before and after treatment with an anti-IL-2r antibody.

RESULTS

The median time from transplantation to SRR was 25 days. Secondary immunosuppression included mycophenolate mofetil in 18 patients. Twelve patients (48%) had complete resolution of SRR. Aspartate transaminase levels normalized at a median of 37 days (range, 1-168 days). In 13 patients (52%) progressive hepatic dysfunction developed. Four of these patients received another transplant, and 6 patients had chronic rejection. Three patients died with graft failure. Of 16 patients with acute cellular rejection, 12 (75%) had resolution, 2 had chronic rejection, 1 required a repeat transplantation, and 1 died with graft failure. In contrast, all 9 patients with established chronic rejection in their pretreatment biopsy continued to have significant graft dysfunction, with 4 having persistent chronic graft dysfunction, 3 requiring repeat transplantation, and 2 dying with graft failure.

CONCLUSION

Twelve (48%) of 25 patients who received an anti-IL-2r antibody because of SRR were successfully treated. All successfully treated patients had ongoing acute cellular rejection at liver biopsy (75%), whereas patients with histologic evidence of chronic rejection responded poorly.

The renal-sparing efficacy of basiliximab in adult living donor liver transplantation

The purpose of this study is to find out whether basiliximab administration will improve postoperative renal function by delaying the start of tacrolimus and decreasing of dosage requirement for tacrolimus in adult living donor liver transplantation (LDLT). Forty-five adult LDLT recipients were enrolled in the study. The induction group (n = 27) was given basiliximab 20 mg on days 0 and 4; tacrolimus administration was delayed until renal function improved. The control group (n = 18) did not receive basiliximab; tacrolimus was given on the first postoperative day. Trough levels of tacrolimus in the induction and control groups were aimed to be maintained at 5-10 ng/ml and 10-15 ng/ml during the first week after transplant, respectively. The median follow-up was 22 months (range 10-34 months). The preoperative conditions were poorer in the induction group (Child C, 56% vs. 33%, P = 0.01; UNOS 2a, 15% vs. 0%, P = 0.02). The intraoperative blood loss was also higher in the induction group than in the control group (median 2,180 ml vs. 495 ml, P < 0.01). The median delay in tacrolimus administration in the induction group was 36 hours (range 24-108 hours). Serum creatinine levels at second and third postoperative months were significantly lower in the induction group. The creatinine clearance rate in the induction group was higher at the third month posttransplant (median 72 vs. 57 ml/minute, P = 0.04). The incidence of renal insufficiency was significantly lower in the induction group at the third month posttransplant (26% vs. 67%, P < 0.01). Blood cholesterol level at the sixth month posttransplant was lower in the induction group (median 152 vs. 196 mg/dl P = 0.03). The incidences of acute cellular rejection, bacteremia, and cytomegalovirus (CMV) infection were similar in both groups. In conclusion, for pretransplant critical patients with more intraoperative blood loss, basiliximab induction could prevent early renal dysfunction by delaying the start of tacrolimus and reducing the dose requirement of tacrolimus without increasing graft rejection and infection. Furthermore, it also improved renal function as well as lowered cholesterol levels within 6 months after transplantation.

Infectious risk in pediatric organ transplant recipients: is it increased with the new immunosuppressive agents?

The risk of infection in pediatric organ transplant recipients is determined by several factors, including age, the types of organ transplanted and the immunosuppressive treatment which has dramatically changed over the past 10 yr. Little information has been reported regarding the infectious complications related to the current immunosuppressive protocols used in these children. This paper reviews (i) the immunosuppressive agents, focusing on their mechanisms of action and on the new regimens, (ii) the infections related to excessive immunosuppression and also anti-infectious properties or infectious adverse reactions associated with specific immunosuppressive agents. With the new immunosuppressive protocols, the advances in immunologic monitoring, microbiological diagnosis, anti-infectious prophylactic and preemptive treatments, strategies to minimize the risk of infection related to the immunosuppressive therapy are proposed.

Anti-IL-2 receptor antibody vs. polyclonal anti-lymphocyte antibody as induction therapy in pediatric transplantation

Current concerns in pediatric transplantation focus on chronic rejection which commonly leads to graft loss, and on long-term maintenance immunosuppression toxicity. Acute rejection has been associated with the subsequent development of chronic rejection. Therefore, induction therapy may provide potential benefits by preventing early acute rejection episodes and allowing delayed administration of calcineurin inhibitors or steroid avoidance. This review of the literature showed that induction therapy can reduce early and recurrent acute rejection episodes after pediatric solid organ transplantation. Whether this might result in better long-term graft survival has still to be confirmed. However, induction therapy has beneficial effects in high-risk recipients and allows steroid avoidance or calcineurin inhibitor minimization. Because they are very well tolerated, anti-IL-2 receptor antibodies are increasingly preferred to rabbit-antithymocyte globulin, but the former have not yet been proven to be more effective or to have less late toxicity than polyclonal agents. Benefits in early outcome and no increase in adverse events lead to recommend the use of IL-2 receptor antagonists as induction therapy after pediatric organ transplantation.

Enhanced donor-specific alloreactivity occurs independently of immunosuppression in children with early liver rejection

To determine whether early acute cellular rejection (ACR) is associated with sub-optimal immunosuppression in children with liver transplants (LTx).

METHODS

Twenty-five children with primary LTx after pre-transplant rabbit anti-thymocyte globulin (rATG), and steroid-free tacrolimus (TAC) were evaluated. Mitogen-stimulated T- and B-cell responses and mixed lymphocyte response to donor and third-party antigens were performed at several time points between two consecutive TAC doses. TAC concentrations (C) associated with half-maximal effect (EC(50)) on lymphocytes was determined by pharmacodynamic equations.

RESULTS

Mean age was 7.2 +/- 6.2 years, mean time to lymphocyte function studies was 25 +/- 19 days. Acute rejection occurred at a mean interval of 31 +/- 19 days after LTx. Rejectors (n = 16) demonstrated significantly higher EC(50) of TAC for the intra-cellular IFN-gamma in T cells (p = 0.005) and its CD8+ sub-population (p = 0.027) as well as the co-stimulatory/activation receptor CD54 on B cells (p = 0.0001). The response of recipient lymphocytes to donor antigen was significantly higher in rejectors, compared with non-rejectors (p = 0.015). The patient groups demonstrated no differences in third-party MLR, or in C of TAC.

CONCLUSIONS

Independent of the amount of immunosuppressant, ACR of liver allografts in children is associated with enhanced donor-specific alloreactivity. This is accompanied by a cytotoxic T-cell sub-population with increased requirement for TAC.

Early postoperative complications in recipients of living donor liver transplantation

PURPOSE

Complications are common in the early postoperative period after living donor liver transplantation (LDLT). The aims of this analysis were to describe and identify risk factors for early postoperative complications.

METHODS

Between June 1994 and June 2003, 140 consecutive LDLT patients were divided into 3 groups: group I was small infants <9 kg (n = 30); group II, pediatric patients (n = 63); and group III, adult patients (n = 47). The complications within 3 months after operation were analyzed.

RESULTS

The mortality rate was 1.4%. Surgical complications requiring relaparotomy occurred in 7.9% of patients. Intraoperative portal vein thrombosis requiring immediate thrombectomy, which occurred in 10 patients, was significantly more frequent in the small infant group (23.1% vs 3.2% vs 2.1%; P < .01). Acute hepatic artery thrombosis that occurred in 2 patients was remedied successfully using operative rearterilization. Hepatic outflow obstruction requiring radiological interventions developed in 5 subjects. Medical complications included the following: pulmonary (14.3%), renal (19.3%), bacteremia (10.7%), cytomegalovirus infection (9.3%), and drain-related infections (20.7%). The incidence of hospital-acquired renal insufficiency was significantly higher in adult patients (3.3% vs 14.3% vs 36.2%; P < .01). There was no significant difference in the incidence of acute cellular rejection between members of the 3 groups (10.0% vs 17.5% vs 17%; P = .63).

CONCLUSIONS

Sophisticated postoperative care with multiple disciplinary involvements may achieve a low early mortality rate in LDLT. Small infants weighing <9 kg may carry a greater risk of intraoperative portal vein thrombosis. Pulmonary complications and renal function impairments were the most troublesome in pediatric and adult recipients, respectively.

Pediatric liver transplantation

PURPOSE OF REVIEW

Pediatric liver transplantation is a challenging and exciting field for all healthcare providers involved with children who have end-stage liver disease. Graft and patient survival continue to improve due to improvements in medical, surgical, and anesthetic management, organ availability, immunosuppression, and identification and treatment of postoperative complications. This review will describe recent advances in pediatric liver transplantation.

RECENT FINDINGS

Although pediatric cases only represent approximately 10% of the total patients on the waiting list, the number of deaths on the waiting list increased from 196 to 1753 between 1988 and 1999. Recently, a new pediatric liver allocation policy was instituted. The utilization of cut down "reduced" livers, split liver grafts, and living-related donors has provided more organs for pediatric patients. Newer immunosuppression regimens, including induction therapy, continue to have a significant impact on graft and patient survival. Excellence in peri-operative management and identification and treatment of complications or infections also has had an impact on graft and patient survival. Finally, investigation and analysis of the postoperative quality of life, for both the patient and parents, is being conducted.

SUMMARY

Pediatric liver transplantation is a challenging and rewarding field with continued improvements in patient and graft survival. A multidisciplinary team approach coupled with improvements in organ availability, immunosuppression, and peri-operative management has had a dramatic impact on survival.

Evolution of immunosuppression in liver transplantation: contribution of cyclosporine

Liver transplantation has become the standard therapy for patients with end-stage liver disease or acute liver failure, with excellent outcomes in terms of quality of life and length of survival. The use of immunosuppressive agents, without any doubt, has played a crucial role in the establishment of this technique and improved short- and long-term survival rates. Eventually, mortality from acute or chronic rejection may be entirely eliminated. Minimizing the adverse effects of immunosuppressive agents is essential to improve long-term survival and quality of life. In this chapter, we review the history of immunosuppressive agents for liver transplantation with consideration of the pre- and the postcyclosporine eras. We also review the development and contributions of cyclosporine, the excellent outcomes from C2 monitoring, comparisons between the cyclosporine microemulsion and the oil-based formula, as well as between cyclosporine microemulsion versus tacrolimus. In addition, details are provided on the newer immunosuppressive agents: mycophenolate mofetil, sirolimus, and the IL-2 receptor antagonists, as well as agents in development: CAMPATH 1-H, thymoglobulin, everolimus, FT720, and FK778.

Peripheral eosinophilia and eosinophilic gastroenteritis after pediatric liver transplantation

Reports indicate peripheral eosinophilia (PE) and gastrointestinal eosinophilic inflammation can occur after pediatric liver transplantation. The incidence of these conditions, potential risk factors, and the impact of PE and gastrointestinal eosinophilic inflammation on liver transplant outcome were determined in this pediatric liver transplant program. Medical records of liver transplant recipients from 1 to 97 and from 12 to 99 were reviewed. Fifty-seven transplants on 54 patients were performed during the study period. Fifty-three patients were evaluated; all had normal pre-transplantation peripheral eosinophil counts. PE of > 10% developed in 28% of patients. Using this definition, all such identified patients had absolute eosinophil counts of > 350/mm3. History of immediate hypersensitivity did not differ between patients with or without eosinophilia. Gastrointestinal endoscopy and biopsy was performed in 23 patients with gastrointestinal complaints. Of those, six had eosinophilic gastroenteritis and all six had PE. Compared with patients without eosinophilia, those with PE were younger at the time of transplantation (p < 0.05), had more frequent rejection (p < 0.01), were more commonly managed with tacrolimus-based immunosuppression (p < 0.001), and experienced more frequent episodes of detectable EBV viral load (p < 0.04). Patients with eosinophilic gastroenteritis were more frequently retransplanted (p < 0.006). PE associated with symptomatic eosinophilic gastroenteritis is common after pediatric liver transplantation. Age at transplant, frequency of rejection episodes, tacrolimus-based immunosuppression, and EBV viral load may be associated with the development of this condition. There may be higher rates of graft loss in such patients. Whether innate immune responsiveness or an acquired immune dysregulation accounts for these findings merits further evaluation.