The IPTA Nashville Consensus Conference on Post-Transplant lymphoproliferative disorders after solid organ transplantation in children: III - Consensus guidelines for Epstein-Barr virus load and other biomarker monitoring

The International Pediatric Transplant Association convened an expert consensus conference to assess current evidence and develop recommendations for various aspects of care relating to post-transplant lymphoproliferative disorders after solid organ transplantation in children. In this report from the Viral Load and Biomarker Monitoring Working Group, we reviewed the existing literature regarding the role of Epstein-Barr viral load and other biomarkers in peripheral blood for predicting the development of PTLD, for PTLD diagnosis, and for monitoring of response to treatment. Key recommendations from the group highlighted the strong recommendation for use of the term EBV DNAemia instead of "viremia" to describe EBV DNA levels in peripheral blood as well as concerns with comparison of EBV DNAemia measurement results performed at different institutions even when tests are calibrated using the WHO international standard. The working group concluded that either whole blood or plasma could be used as matrices for EBV DNA measurement; optimal specimen type may be clinical context dependent. Whole blood testing has some advantages for surveillance to inform pre-emptive interventions while plasma testing may be preferred in the setting of clinical symptoms and treatment monitoring. However, EBV DNAemia testing alone was not recommended for PTLD diagnosis. Quantitative EBV DNAemia surveillance to identify patients at risk for PTLD and to inform pre-emptive interventions in patients who are EBV seronegative pre-transplant was recommended. In contrast, with the exception of intestinal transplant recipients or those with recent primary EBV infection prior to SOT, surveillance was not recommended in pediatric SOT recipients EBV seropositive pre-transplant. Implications of viral load kinetic parameters including peak load and viral set point on pre-emptive PTLD prevention monitoring algorithms were discussed. Use of additional markers, including measurements of EBV specific cell mediated immunity was discussed but not recommended though the importance of obtaining additional data from prospective multicenter studies was highlighted as a key research priority.

The IPTA Nashville consensus conference on Post-Transplant lymphoproliferative disorders after solid organ transplantation in children: II-consensus guidelines for prevention

The International Pediatric Transplant Association (IPTA) convened an expert consensus conference to assess current evidence and develop recommendations for various aspects of care relating to post-transplant lymphoproliferative disorder after solid organ transplantation in children. In this report from the Prevention Working Group, we reviewed the existing literature regarding immunoprophylaxis and chemoprophylaxis, and pre-emptive strategies. While the group made a strong recommendation for pre-emptive reduction of immunosuppression at the time of EBV DNAemia (low to moderate evidence), no recommendations for use could be made for any prophylactic strategy or alternate pre-emptive strategy, largely due to insufficient or conflicting evidence. Current gaps and future research priorities are highlighted.

Operational tolerance after intestine re-transplantation in childhood and immunological correlates. Case report and review

BACKGROUND

Operational tolerance after retransplantation of the intestine has never been reported.

PURPOSE

To two recently described intestine transplant recipients with operational tolerance, we now add a third.

METHODS

Review of case record and immunological testing to confirm donor-specific hyporesponsiveness in multiple immune cell compartments.

RESULTS

Re-transplanted with a multivisceral liver- and kidney-inclusive intestine allograft at age 12 years, this recipient self-discontinued immunosuppression 14 years after the retransplant and has been rejection free for 2 years thereafter. As in the two previous reports, immunological testing demonstrated decreased donor-specific inflammatory response of T-cytotoxic memory cells and B-cells, decreased presentation of donor antigen by B-cells and monocytes, absence of donor-specific anti-HLA antibodies, circulating FOXP3 + T-helper cells, and intact cellular and humoral immunity to cytomegalovirus and Epstein-Barr virus. Additionally, our recipient demonstrated enhanced donor-activation-induced apoptosis of alloreactive T-cytotoxic memory cells.

CONCLUSIONS

Despite variable paths to tolerance which include graft versus host disease in two previous cases, and rejection-related loss of the primary isolated intestinal allograft in our recipient, the three cases with operational tolerance are bound by common themes: a relatively large donor antigenic load transmitted during intestine transplantation, and donor-specific hyporesponsiveness. Cell-based assays suggest enhanced donor-induced apoptosis of recipient T-cells and circulating T-regulatory cells as mechanistic links between antigenic load and donor-specific hyporesponsiveness.

Increased use of split liver grafts in adult recipients following implementation of a pediatric liver transplant program

BACKGROUND

Split liver transplantation (SLT) is a strategy to address organ shortage, but is a technically more demanding procedure than whole graft liver transplantation (LT). We aimed to determine the outcomes following SLT in adult recipients as well as to highlight the impact that having a pediatric LT program has on SLT implementation.

METHODS

All SLTs conducted at a single-center from 2010 to 2019 were identified. Patient data was obtained through retrospective review of the electronic medical record. Kaplan-Meier analysis assessed primary outcomes of 1-,3-, and 5-year graft and patient survival.

RESULTS

We identified 37 SLTs performed at our institution from 2010 to 2019. Twenty-four donated livers resulted in 21 extended right lobes and 16 left lateral segments for adults and pediatrics recipients, respectively. Eighty-one percent (30/37) of the SLTs were performed after introduction of the combined pediatric program in 2016. 13/24 donor livers were split with both grafts allocated and used at our institution and 92% occurred after introduction of the pediatric program. Graft survival rates at 1-, 3-, and 5-years were 94% in adult recipients and 100% for all time periods in pediatric recipients. Actuarial post-transplant patient survival was 100% at 1-, 3-, and 5-years in both.

CONCLUSIONS

The introduction of a pediatric liver transplantation program resulted in more than a fourfold increase in the number of SLTs performed at our center. Increase in allocation and use of both grafts at our institution was also seen.

Long term management of liver transplant rejection in children

The current management of hepatic allograft rejection after liver transplantation in children requires effective baseline immunosuppression to prevent rejection and rapid diagnosis and treatment to manage acute rejection episodes. The subsequent impact on chronic rejection is dependent on the combination of adequate prevention and the treatment of acute rejection. Tacrolimus is a macrolide lactone that inhibits the signal transduction of interleukin-2 (IL-2) via calcineurin inhibition. Introduced in 1989, tacrolimus was first used in the salvage of refractory acute or chronic rejection under cyclosporin or to rescue patients with significant cyclosporin-related complications. The majority of paediatric transplant centres use a combination of steroids with tacrolimus as a basic immunosuppressant regimen following paediatric liver transplantation. This combination has allowed the acute cellular rejection-free rate to increase to between 30 and 60%, while lowering the rate of refractory rejection to less than 5%. Corticosteroid-resistant rejection is commonly treated with monoclonal (muromonab CD3) or polyclonal preparations. Although most episodes of acute cellular rejection occur during the first 6 weeks after liver transplant, the appearance of late acute liver allograft rejection must raise the question of noncompliance, especially in the adolescent population. Chronic rejection is becoming increasingly rare under tacrolimus-based immunosuppression. Tacrolimus is effective in reversing refractory acute cellular rejection or early chronic rejection in patients initially treated with cyclosporin-based regimens. Patients with a history of noncompliance as well as children with autoimmune liver disease are at risk of chronic rejection. Retransplantation therapy for chronic rejection has, fortunately, become more rare in the tacrolimus era with only 3% of retransplants being performed for this indication. Newer immunosuppressive agents are further modifying the long term management of liver allograft rejection. These include mycophenolate mofetil, rapamycin and IL-2 antibodies such as daclizumab. The development of these agents is allowing patient-specific immunosuppressive management to minimise rejection as well as the complications related to immunosuppression.

Intestine transplantation in the United States, 1999-2008

Improving short-term results with intestine transplantation have allowed more patients to benefit with nearly 700 patients alive in the United States with a functioning allograft at the end of 2007. This success has led to an increase in demand. Time to transplant and waiting list mortality have significantly improved over the decade, but mortality remains high, especially for infants and adults with concomitant liver failure. The approximately 200 intestines recovered annually from deceased donors represent less than 3% of donors who have at least one organ recovered. Consent practice varies widely by OPTN region. Opportunities for improving intestine recovery and utilization include improving consent rates and standardizing donor selection criteria. One-year patient and intestine graft survival is 89% and 79% for intestine-only recipients and 72% and 69% for liver-intestine recipients, respectively. By 10 years, patient and intestine survival falls to 46% and 29% for intestine-only recipients, and 42% and 39% for liver-intestine, respectively. Immunosuppression practice employs peri-operative antibody induction therapy in 60% of cases; acute rejection is reported in 30%-40% of recipients at one year. Data on long-term nutritional outcomes and morbidities are limited, while the cause and therapy for late graft loss from chronic rejection are areas of ongoing investigation.

Long-term management of the liver transplant patient: recommendations for the primary care doctor

No official document has been published for primary care physicians regarding the management of liver transplant patients. With no official source of reference, primary care physicians often question their care of these patients. The following guidelines have been approved by the American Society of Transplantation and represent the position of the association. The data presented are based on formal review and analysis of published literature in the field and the clinical experience of the authors. These guidelines address drug interactions and side effects of immunosuppressive agents, allograft dysfunction, renal dysfunction, metabolic disorders, preventive medicine, malignancies, disability and productivity in the workforce, issues specific to pregnancy and sexual function, and pediatric patient concerns. These guidelines are intended to provide a bridge between transplant centers and primary care physicians in the long-term management of the liver transplant patient.

Liver and intestine transplantation in the United States 1998-2007

Liver transplantation numbers in the United States remained constant from 2004 to 2007, while the number of waiting list candidates has trended down. In 2007, the waiting list was at its smallest since 1999, with adults > or =50 years representing the majority of candidates. Noncholestatic cirrhosis was most commonly diagnosed. Most age groups had decreased waiting list death rates; however, children <1 year had the highest death rate. Use of liver allografts from donation after cardiac death (DCD) donors increased in 2007. Model for end-stage liver disease (MELD)/pediatric model for end-stage liver disease (PELD) scores have changed very little since 2002, with MELD/PELD <15 accounting for 75% of the waiting list. Over the same period, the number of transplants for MELD/PELD <15 decreased from 16.4% to 9.8%. Hepatocellular carcinoma exceptions increased slightly. The intestine transplantation waiting list decreased from 2006, with the majority of candidates being children <5 years old. Death rates improved, but remain unacceptably high. Policy changes have been implemented to improve allocation and recovery of intestine grafts to positively impact mortality. In addition to evaluating trends in liver and intestine transplantation, we review in depth, issues related to organ acceptance rates, DCD, living donor transplantation and MELD/PELD exceptions.

Late graft loss or death in pediatric liver transplantation: an analysis of the SPLIT database

Late graft loss (LGL) and late mortality (LM) following liver transplantation (LT) in children were analyzed from the studies of pediatric liver transplantation (SPLIT) database. Univariate and multivariate associations between pre- and postoperative factors and LGL and LM in 872 patients alive with their primary allografts 1 year after LT were reviewed. Thirty-four patients subsequently died (LM) and 35 patients underwent re-LT (LGL). Patients who survive the first posttransplant year had 5-year patient and graft survival rates of 94.2% and 89.2%, respectively. Graft loss after the first year was caused by rejection in 49% of the cases with sequelae of technical complications accounting for an additional 20% of LGL. LT for tumor, steroid resistant rejection, reoperation in the first 30 days and >5 admissions during the first posttransplant year were independently associated with LGL in multivariate analysis. Malignancy, infection, multiple system organ failure and posttransplant lymphoproliferative disease accounted for 61.8% of all late deaths after LT. LT performed for FHF and tumor were associated with LM. Patients who are at or below the mean for weight at the time of transplant were also at an increased risk of dying. Frequent readmission was also found to be associated with LM.

Elective liver transplantation for the treatment of classical maple syrup urine disease

An 8.5-year-old girl with classical maple syrup urine disease (MSUD) required liver transplantation for hypervitaminosis A and was effectively cured of MSUD over an 8-year clinical follow-up period. We developed a collaborative multidisciplinary effort to evaluate the effects of elective liver transplantation in 10 additional children (age range 1.9-20.5 years) with classical MSUD. Patients were transplanted with whole cadaveric livers under a protocol designed to optimize safe pre- and post-transplant management of MSUD. All patients are alive and well with normal allograft function after 106 months of follow-up in the index patient and a median follow-up period of 14 months (range 4-18 months) in the 10 remaining patients. Leucine, isoleucine and valine levels stabilized within 6 hours post-transplant and remained so on an unrestricted protein intake in all patients. Metabolic cure was documented as a sustained increase in weight-adjusted leucine tolerance, normalization of plasma concentration relationships among branched-chain and other essential and nonessential amino acids, and metabolic and clinical stability during protein loading and intercurrent illnesses. Costs and risks associated with surgery and immune suppression were similar to other pediatric liver transplant populations.

Conversion from cyclosporin to tacrolimus in paediatric liver transplant recipients

Substitution of cyclosporin with tacrolimus should be considered for paediatric liver transplant recipients with cyclosporin-associated complications such as hypertension, gum hyperplasia, hirsutism, gynaecomastia and growth retardation, as well as recurrent or refractory acute rejection, chronic duct injury or chronic rejection. Continued experience with well tolerated drug administration and careful monitoring during drug substitution has limited drug toxicity associated with tacrolimus to a level comparable to or less than that associated with cyclosporin. Successful outcome with long term graft salvage has been reported in up to 80% of patients converted to tacrolimus because of acute rejection and 50% of patients converted because of chronic rejection. Nearly all children converted because of cyclosporin-related complications have a successful outcome. Additional benefits of conversion to tacrolimus include improvement in growth and resolution of hypertension, hirsutism and cushingoid facies. Complete corticosteroid withdrawal is possible in up to 78% of children post-conversion. Long term outcome in these patients may be optimised by conversion to tacrolimus at an early stage of acute or chronic transplant rejection in order to minimise the cumulative amount of immunosuppression. Avoidance of cyclosporin-related toxicity and minimisation of corticosteroid therapy may further improve patient compliance to drug therapy.

Clinical and laboratory evaluation of the safety of a bioartificial liver assist device for potential transmission of porcine endogenous retrovirus

BACKGROUND

The potential risk of transmission of porcine endogenous retroviruses (PERV) from xenogeneic donors into humans has been widely debated. Because we were involved in a phase I/II clinical trial using a bioartificial liver support system (BLSS), we proceeded to evaluate the biosafety of this device.

MATERIALS AND METHODS

The system being evaluated contains primary porcine hepatocytes freshly isolated from pathogen-free, purpose-raised herd. Isolated hepatocytes were installed in the shell, which is separated by a semipermeable membrane (100-kD nominal cutoff) from the lumen through which the patients' whole blood is circulated. Both before and at defined intervals posthemoperfusion, patients' blood was obtained for screening. Additionally, effluent collected from a clinical bioreactor was analyzed. The presence of viral particles was estimated by reverse transcriptase-polymerase chain reaction (RT-PCR) and RT assays. For the detection of pig genomic and mitochondrial DNA, sequence-specific PCR (SS-PCR) was used. Finally, the presence of infectious viral particles in the samples was ascertained by exposure to the PERV-susceptible human cell line HEK-293.

RESULTS

PERV transcripts, RT activity, and infectious PERV particles were not detected in the luminal effluent of a bioreactor. Culture supernatant from untreated control or mitogen-treated porcine hepatocytes (cleared of cellular debris) also failed to infect HEK-293 cell lines. Finally, RT-PCR, SS-PCR, and PERV-specific RT assay detected no PERV infection in the blood samples obtained from five study patients both before and at various times post-hemoperfusion.

CONCLUSION

Although longer patient follow-up is required and mandated to unequivocally establish the biosafety of this device and related bioartificial organ systems, these analyses support the conclusion that when used under standard operational conditions, the BLSS is safe.

Monitoring the patient off immunosuppression. Conceptual framework for a proposed tolerance assay study in liver transplant recipients

The mission of the recently established Immune Tolerance Network includes the development of protocols for the induction of transplant tolerance in organ allograft recipients and the development of assays that correlate with and may be predictive of the tolerant state. The state of clinical organ transplant tolerance seems to already exist in a small minority of conventionally immunosuppressed liver and, more rarely, kidney transplant patients. Immunosuppressive drug therapy has been withdrawn from these patients for a variety of reasons, including protocolized weaning for a uniquely large group of liver patients at the University of Pittsburgh. In this study, we propose to evaluate the validity of a variety of in vitro immunologic and molecular biologic tests that may correlate with, and be predictive of, the state of organ transplant tolerance in stable liver patients off immunosuppression. Only peripheral blood will be available for the execution of these tests. Both adult and pediatric liver graft recipients will be studied, in comparison to appropriate controls. We shall examine circulating dendritic cell (DC) subsets [precursor (p) DC1 and p DC2] including cells of donor origin, and assess both the frequency and function of donor-reactive T cells by ELISPOT and by trans-vivo delayed-type hypersensitivity analysis in a surrogate murine model. Cytokine gene polymorphism and alloantibody titers will also be investigated. It is anticipated that the results obtained may provide physicians with a tolerance assay "profile" that may determine those patients from whom immunosuppressive therapy may be safely withdrawn.

Primary tacrolimus (FK506) therapy and the long-term risk of post-transplant lymphoproliferative disease in pediatric liver transplant recipients

While the overall incidence of post-transplant lymphoproliferative disease (PTLD) in pediatric liver transplant recipients has been reported to be 4-11%, the long-term risk of PTLD associated with primary tacrolimus therapy is unknown. Therefore, in order to determine the incidence and long-term risk of PTLD, the present study examined 131 pediatric recipients who underwent liver transplantation (LTx) between October 1989 and December 1991 and received primary tacrolimus therapy. This cohort of children was evaluated over an extended time-period (until December 31 1996) with a mean follow-up of 6.3 yr. Actuarial Kaplan-Meier analysis was utilized to determine the risk of PTLD over time. The overall incidence of PTLD was 13% (17/131) with an average age of 4.3 +/- 0.75 yr at diagnosis. Pretransplant Epstein-Barr virus (EBV) serologies were negative in 82%, positive in 12%, and not available in 6% of the patients. The median time to diagnosis of PTLD post-Tx was 11.9 months (mean 16.4 +/- 3.9, range 1.7-63.0 months). Mean tacrolimus dose and plasma trough level (as evaluated by enzyme-linked immunosorbent assay [ELISA]) at the time of diagnosis was 0.32 +/- 0.06 mg/kg/day and 1.3 +/- 0.3 ng/mL, respectively. The cumulative long-term risk of PTLD was found to increase over time: 3% at 6 months, 8% at 1 yr, 12% at 2 yr, 14% at 3 yr, and 15% at 4 and 5 yr. Mortality from PTLD was 12% (two of 17 patients). Primary tacrolimus use in pediatric LTx has a long-term risk of PTLD approaching 15%, with the majority of episodes (78%) occurring in the first 2 yr, suggesting that intense EBV surveillance should occur early post-transplantation.

Safety observations in phase I clinical evaluation of the Excorp Medical Bioartificial Liver Support System after the first four patients

A Phase I clinical safety evaluation of the Excorp Medical, Inc, Bioartificial Liver Support System (BLSS) is in progress. Inclusion criteria are patients with acute liver failure of any etiology, presenting with encephalopathy deteriorating beyond Parson's Grade 2. The BLSS consists of a blood pump, heat exchanger to control blood temperature, oxygenator to control oxygenation and pH, bioreactor, and associated pressure and flow alarm systems. Patient liver support is provided by 70-100 g of porcine liver cells housed in the hollow fiber bioreactor. A single support period evaluation consists of 12 hour extracorporeal perfusion with the BLSS sandwiched between 12 hours of pre (baseline) and 12 hours of post support monitoring. Blood chemistries and hematologies are obtained every 6 hours during monitoring periods and every 4 hours during perfusion. Physiologic parameters are monitored continuously. The patient may receive a second treatment at the discretion of the clinical physician. Preliminary evaluation of safety considerations after enrollment of the first four patients (F, 41, acetaminophen induced, two support periods; M, 50, Wilson's disease, one support period; F, 53, acute alcoholic hepatitis, two support periods; F, 24, chemotherapy induced, one support period) is presented. All patients tolerated the extracorporeal perfusion well. All patients presented with hypoglycemia at the start of perfusion, treatable by IV dextrose. Transient hypotension at the start of perfusion responded to an IV fluid bolus. Only the second patient required heparin anticoagulation. No serious or unexpected adverse events were noted. Moderate biochemical response to support was noted in all patients. Completion of the Phase I safety evaluation is required to fully characterize the safety of the BLSS.

Analysis of patients with longitudinal intestinal lengthening procedure referred for intestinal transplantation

BACKGROUND/PURPOSE

Longitudinal intestinal lengthening procedures (LILP) in patients with short gut syndrome (SGS) enhances small intestinal peristalsis and decreases bacterial overgrowth without reducing absorptive surface. Therefore, patients theoretically may be easily weaned off TPN. The aim of this study was to evaluate the impact of failed LILP in SGS patients referred for intestinal transplantation.

METHODS

Twenty-seven (11%) of 230 children with SGS and total parenteral nutrition (TPN) dependency evaluated for intestinal transplantation at our institution had undergone LILP. This was performed at a mean age of 1.7 years (range, 1 day to 14.7 years); the mean age at the time of evaluation was 3.3 years (range, 0.4 to 17 years). Two patients underwent LILP immediately after birth. The principle diagnoses producing SGS were gastroschisis (n = 8), intestinal atresia (n = 11), neonatal volvulus (n = 7) and necrotizing enterocolitis (n = 1). Before LILP, the mean length of intestine was 32 cm (range, 8 to 70 cm). Fifteen (56%) patients had jaundice at the time of evaluation.

RESULTS

All but one child were considered candidates for intestinal transplantation. The mean intestinal length achieved after LILP was 48 cm (range, 16 to 100). The mean follow-up from the date of LILP was 876 days (range, 109 to 4,109 days). After LILP, only 9 (33%) patients increased their caloric intake through the enteral route by > or =50%, and only 1 patient could be weaned off TPN. In the patients with liver dysfunction at the time of LILP, none recovered. Most of the patients had multiple episodes of sepsis after LILP. Fourteen (52%) of 27 patients underwent intestinal transplantation, 7 combined with a liver allograft because of TPN-induced end-stage liver disease. Six of the transplanted patients are alive and TPN free. Of the remaining 13 (48%) nontransplanted patients, 9 patients died. The main cause of death was TPN-induced liver failure. Three patients are on partial TPN, and only 1 patient was weaned off TPN. The presence of an ileocecal valve did not impact on outcome. Surprisingly, patients with > or =50% of colon at the time of LILP had poorer survival than those with less. Twelve (44%) of 27 patients had surgical complications, and in both patients with LILP performed in the neonatal period it failed immediately with acute complications. There were no differences in patient survival rate for patients with SGS without LILP (n = 203) and those with LILP (n = 27).

CONCLUSION

Based on patients with unsuccessful LILP referred for intestinal transplantation, we believe this procedure should be avoided in the neonatal period, in those patients with liver dysfunction, and when intestinal length is <50 cm.

Management of hepatic venous obstruction after split-liver transplantation

Stenosis of the hepatic vein anastomosis is an unusual but critical complication after liver transplantation. In pediatric liver transplantation, the scarcity of size-matched donors has required the use of segmental liver allografts, either as reduced-size or split-liver grafts. This report illustrates the primary use of a hepatic vein stent to manage hepatic venous outflow obstruction in a pediatric split-liver recipient, and reviews experience in the management of hepatic venous outflow obstruction after liver transplant using stent methods.

Intrahepatic chemoembolization in unresectable pediatric liver malignancies

OBJECTIVE

To determine the effectiveness of a new multidisciplinary approach using neoadjuvant intrahepatic chemoembolization (IHCE) and liver transplant (OLTx) in patients with unresectable hepatic tumors who have failed systemic chemotherapy.

MATERIALS AND METHODS

From November 1989 to April 1998, 14 children (2-15 years old) were treated with 50 courses of intra-arterial chemotherapy. Baseline and post-treatment contrast-enhanced CT and alpha-fetoprotein levels were performed. Seven had hepatoblastoma, and 7 had hepatocellular carcinoma (1 fibrolamellar variant). All patients had subselective hepatic angiography and infusion of cisplatin and/or adriamycin (36 courses were followed by gelfoam embolization). The procedure was repeated every 3-4 weeks based on hepatic function and patency of the hepatic artery.

RESULTS

Six of 14 children received orthotopic liver transplants (31 courses of IHC). Pretransplant, 3 of 6 showed a significant decrease in alpha-fetoprotein, while only 1 demonstrated a significant further reduction in tumor size). Three of 6 patients are disease free at this time. Three of 6 patients died of metastatic tumor 6, 38, and 58 months, respectively post-transplant. One of 14 is currently undergoing treatment, has demonstrated a positive response, and is awaiting OLTx. Three of 14 withdrew from the program and died. Four of 14 patients developed an increase in tumor size, developed metastatic disease, and were not transplant candidates. Two hepatic arteries thrombosed, and one child had a small sealed-off gastric ulcer as complications of intrahepatic chemoembolization.

CONCLUSION

The results of intrahepatic chemoembolization are promising and suggest that some children who do not respond to systemic therapy can be eventually cured by a combination of intrahepatic chemoembolization orthotopic liver transplant. Alpha-fetoprotein and cross-sectional imaging appear to be complementary in evaluating tumor response. IHCE does not appear to convert an anatomically unresectable lesion to a candidate for partial hepatectomy.

Liver transplantation and chemotherapy for hepatoblastoma and hepatocellular cancer in childhood and adolescence

OBJECTIVE

To describe our experience with total hepatectomy and liver transplantation as treatment for primary hepatoblastoma (HBL) and hepatocellular carcinoma (HCC) in children.

STUDY DESIGN

A retrospective analysis of the perioperative course of 31 children with unresectable primary HBL (n = 12) and HCC (n = 19) who underwent transplantation between May 1989 and December 1998. Systemic (n = 18) and intraarterial (n = 7) neoadjuvant chemotherapy were administered; follow-up ranged from 1 to 185 months.

RESULTS

For HBL, 1-year, 3-year, and 5-year posttransplantation survival rates were 92%, 92%, and 83%, respectively. Intravenous invasion, positive hilar lymph nodes, and contiguous spread did not have a significant adverse effect on outcome; distant metastasis was responsible for 2 deaths. Intraarterial chemotherapy was effective in all patients treated. For HCC, the overall 1-year, 3-year, and 5-year disease-free survival rates were 79%, 68%, and 63%, respectively. Vascular invasion, distant metastases, lymph node involvement, tumor size, and gender were significant risk factors for recurrence. Intraarterial chemotherapy was effective in 1 of 3 patients. Six patients died of recurrent HCC, and 3 deaths were unrelated to recurrent tumor.

CONCLUSION

Liver transplantation for unresectable HBL and HCC can be curative. Risk factors for recurrence were significant only for HCC, with more advanced stages amenable to cure in the HBL group.

Acute liver failure: clinical features, outcome analysis, and applicability of prognostic criteria

Acute liver failure (ALF) is an uncommon condition associated with high morbidity and mortality. We performed a retrospective analysis of patients evaluated for ALF. The aim of our study is to determine the clinical features and outcome of such patients and to assess the validity of King's College Hospital (KCH) prognostic criteria. One hundred seventy-seven patients were evaluated for ALF during a period of 13 years. Mean age was 39 years, and 63% were women. The causes included viral hepatitis (31%), acetaminophen toxicity (19%), idiosyncratic drug reactions (12%), miscellaneous causes (11%), and an indeterminate group (28%). Twenty-five patients (14%) recovered with medical therapy (group I), 65 patients (37%) died without orthotopic liver transplantation (OLT; group II), and 87 patients (49%) underwent OLT (group III). Patients in group II were older and often had advanced encephalopathy, whereas those in group I had less hyperbilirubinemia and often had hyperacute failure. KCH criteria had high specificity and positive predictive value but low negative predictive value for a poor outcome. We conclude that early prognostication is needed in patients with ALF to assist decision making regarding OLT. The fulfillment of KCH criteria usually predicts a poor outcome, but a lack of fulfillment does not predict survival.

Split-liver transplantation: a comparison of ex vivo and in situ techniques

BACKGROUND/PURPOSE

The expanding applicability of liver transplantation as treatment for end-stage liver disease has fostered a disproportionate increase in liver transplant candidates in the face of an unchanging pool of donor organs. This has resulted in disparities in pretransplant waiting times and deaths. The splitting of a liver allograft allows for the transplantation of 2 recipients, usually an adult and a child, thus providing a means to expand the cadaveric donor pool.

METHODS

The authors present their results on the performance of an ex vivo (back table) split and in situ (in a hemodynamically stable cadaveric donor) split to evaluate safety, applicability, and effectiveness. Between November 1989 through April 1998, 54 split-liver transplant recipient operations were performed (24 pediatric and 30 adult). Thirty donors were procured: the ex vivo splitting yielded 25 grafts from 13 donors (donor age, 24.6+/-11 years), and the in-situ technique yielded 29 grafts from 17 donors (mean donor age of 25.5+/-10.4 years). Five donors involved interinstitutional sharing for which the left side of the graft was kept at the host hospital and the right side grafts were utilized at our center.

RESULTS

Overall 1-year patient survival was 85%, with a graft survival of 72%. Patient survival was similar with ex vivo (74%) as compared with the in situ splitting group (96%; P = .06), as was graft survival in ex vivo (61 %) versus in situ (81%) splitting (P = .15). The pediatric population benefited most from the in situ technique, with a 1-year patient survival rate of 100% with the in situ technique versus the ex vivo technique survival rate of 64% at 1 year (P = .02). The 1-year graft survival comparing these 2 techniques was 83% for the in situ group versus 45% for the ex vivo group. Analysis of the program evolution of split-liver transplantation suggested a time-dependent learning curve, which was applicable to surgical splitting technique, implantation, and recipient selection.

CONCLUSIONS

The principle of splitting livers from cadaveric donors is fundamentally sound and technically feasible. The authors' outcomes analysis using 2 different procurement techniques suggests that the in situ technique is clinically efficacious, can be used alternatively with the ex vivo technique, and is comparable to whole-liver allograft transplantation.

What's new in pediatric organ transplantation

Current progress in organ transplantation is offering new hope for children who have end-stage heart, lung, liver, intestinal, and renal failure. Immunosuppressive regimens have been improved, and newer immunomodulatory strategies are evolving. New areas of investigation, such as genetic modification of xenograft tissues and organs, and strategies to induce tolerance of organs will be key areas of discovery in the next years, leading to increasing involvement of the generalist in the care of children requiring or recovering from transplantation.

An analysis of pretransplantation variables associated with long-term allograft outcome in pediatric liver transplant recipients receiving primary tacrolimus (FK506) therapy

BACKGROUND

The present study analyzes pretransplantation variables associated with long-term liver allograft survival in 278 children who underwent transplantation under primary tacrolimus (FK506) therapy at a single center between October 1989 and October 1996.

METHODS

The influence of 17 pretransplantation variables on long-term liver allograft outcome was analyzed. Donor variables included age, weight, gender, and cold ischemia time. Recipient variables included age, weight, gender, original liver disease, pretransplantation waiting time, previous abdominal surgery, United Network of Organ Sharing (UNOS) status, ABO blood group, bilirubin level, prothrombin time, ammonia level, creatinine level, and reduced-size/split liver grafts.

RESULTS

Overall actuarial graft survival was 79.9% at 1 year, 79.1% at 2 years, and 78.3% at 3, 4, and 5 years. Retransplantation rate was 10.8%. Pretransplantation variables with a significant adverse effect on graft survival by univariate analysis were donor age < or = 1 year (P<0.004), donor weight < or = 10 kg (P<0.003), UNOS status I and II (P<0.007), ABO type O, B, and AB (P<0.03), and reduced-size/split liver grafts (P<0.02). Pretransplantation variables significant by multivariate analysis and therefore independent predictors of inferior graft outcome were donor weight '10 kg (relative risk [RR] 2.91, confidence interval [CI] 1.53-5.51); reduced-size/split liver grafts (RR 2.53, CI 1.30-5.64); and UNOS status I (RR 2.22, CI 1.11-4.43).

CONCLUSIONS

Pediatric liver transplant recipients receiving primary tacrolimus therapy have long-term graft survival rates approaching 80%. UNOS status, donor weight, and the use of reduced-size/split liver grafts are the most important factors affecting survival.

Hyperbaric oxygen therapy for hepatic artery thrombosis after liver transplantation in children

Early hepatic artery thrombosis (HAT) after pediatric orthotopic liver transplantation (OLT) can cause significant morbidity and mortality, leading to liver failure or septic complications requiring urgent retransplantation. Experimental evidence that hyperbaric oxygen (HBO) may ameliorate hepatic ischemic-reperfusion injury led to this study of HBO in pediatric liver transplant recipients who developed HAT. Children undergoing OLT under primary tacrolimus immunosuppression and University of Wisconsin organ preservation between August 1, 1989, and December 31, 1998, who developed HAT were the basis for this study. Patients who developed HAT between March 1, 1994, and December 31, 1998, were treated with HBO therapy until signs of ischemia resolved (absence of fever, normalizing liver injury test results) or for 2 weeks. The pediatric OLTs performed from August 1, 1989, to February 28, 1994, who developed HAT served as a control group. Primary outcome measures were survival, retransplantation rate, time to retransplantation, incidence of hepatic gangrene, and days to collateral formation. Three hundred seventy-five consecutive pediatric patients underwent 416 OLTs between August 1, 1989, and December 31, 1998. Thirty-one patients (7.5%) developed HAT at a mean time of 8.2 days (range, 1 to 52 days) post-OLT. In 17 patients, HBO treatment was begun within 24 hours of HAT or immediately after the revascularization attempt and performed twice daily for 90 minutes at 2.4 atmospheres pressure. Fourteen patients were treated without HBO. None of the HBO-treated patients developed hepatic gangrene. Eight HBO patients (47%) were bridged to retransplantation at a mean time of 157 days (range, 3 to 952 days) after initial OLT and all survived. Mean time to retransplant in the control group was 12.7 days (range, 1 to 64 days). HBO was well tolerated without significant complications. Although there was no significant difference in survival or retransplantation rates, HBO significantly delayed retransplantation, potentially by hastening the development of hepatic artery collaterals.

Novel bioartificial liver support system: preclinical evaluation

Preclinical safety and efficacy evaluation of a novel bioartificial liver support system (BLSS) was conducted using a D-galactosamine canine liver failure model. The BLSS houses a suspension of porcine hepatocytes in a hollow fiber cartridge with the hepatocytes on one side of the membrane and whole blood flowing on the other. Porcine hepatocytes harvested by a collagenase digestion technique were infused into the hollow fiber cartridge and incubated for 16 to 24 hours prior to use. Fifteen purpose-bred male hounds, 1-3 years old, 25-30 kg, were administered a lethal dose, 1.5 g/kg, of D-galactosamine. The animals were divided into three treatment groups: (1b) no BLSS treatment (n = 6); (2b) BLSS treatment starting at 24-26 h post D-galactosamine (n = 5); and (2c) BLSS treatment starting at 16-18 h post D-galactosamine (n = 4). While maintained under isoflurane anesthesia, canine supportive care was guided by electrolyte and invasive physiologic monitoring consisting of arterial pressure, central venous pressure, extradural intracranial pressure (ICP), pulmonary artery pressure, urinary catheter, and end-tidal CO2. All animals were treated until death or death-equivalent (inability to sustain systolic blood pressure > 80 mmHg for 20 minutes despite massive fluid resuscitation and/or dopamine administration), or euthanized at 60 hours. All animals developed evidence of liver failure at 12-24 hours as evidenced by blood pressure lability, elevated ICP, marked hepatocellular enzyme elevation with microscopic massive hepatocyte necrosis and cerebral edema, elevated prothrombin time, and metabolic acidosis. Groups 2b and 2c marginally prolong survival compared with Group 1b (pairwise log rank censored survival time analysis, p = 0.096 and p = 0.064, respectively). Since survival times for Groups 2b and 2c are not significantly different (p = 0.694), the groups were combined for further statistical analysis. Survival times for the combined active treatment Groups 2b and 2c are significantly prolonged versus Group 1b (p = 0.047). These results suggest the novel BLSS reported here can have a significant impact on the course of liver failure in the D-galactosamine canine liver failure model. The BLSS is ready for Phase I safety evaluation in a clinical setting.

Early complications after orthotopic liver transplantation

The cost and impact of early post-transplant complications continue to be high. Diagnosis and management involves a high index of suspicion, rapid diagnostic and therapeutic interventions, and elimination of technical problems. Preoperative assessment of the donor and recipient medical condition and meticulous attention to detail during the technical performance of OLTx are the mainstays in achieving a good outcome.

Pediatric transplantation

Advances in organ preservation, surgical technique, and postoperative care have permitted the rapid development of liver transplantation in children. Consequently, the applicability of this procedure has gone beyond the treatment of life-threatening complications of chronic liver disease and now includes disabling morbidities and quality-of-life issues. The use of hepatic segments for transplantation with reduced or split cadaveric grafts and living-related donors has decreased the mortality of children awaiting liver transplantation. We are presently armed with a new potent immunosuppressive drug, tacrolimus, and an understanding that the migration and grafting of passenger leukocytes of bone marrow origin is the seminal explanation for allograft acceptance. The next forefront will involve manipulation of the process not only for the transplantation of already successful whole organs--such as the liver, kidney, pancreas, and heart--but also in the development of the intestinal transplantation program. Thus, augmentation of leukocyte traffic in unconditioned recipients of cadaver allografts with concomitant intravenous infusion of donor bone marrow cells under the same immunosuppressive management of tacrolimus-prednisone treatment will be the path into the future.

Fulminant hepatic failure

Fulminant hepatic failure is a disease of varied causes and a high mortality rate. A sudden onset, jaundice, hepatic encephalopathy, and multiorgan failure are the hallmarks of this syndrome. The management of patients with FHF requires a multidisciplinary approach and intense monitoring. The availability of liver transplantation has provided the means to rescue such patients from near-certain death. Early prognostication and timely availability of donor livers are requirements for a successful outcome. The development of effective artificial liver support devices may greatly prolong the window of opportunity to provide a donor liver, or alternatively, to allow the native liver to regenerate.

Factors impacting the survival of children with intestinal failure referred for intestinal transplantation

PURPOSE

The aim of this study was to analyze factors impacting on the survival of pediatric patients with intestinal failure referred for intestinal transplantation (ITx).

METHODS

Two hundred fifty-seven children (mean age, 3.4+/-0.26 years) with intestinal failure were evaluated for ITx between 1990 and 1998. All patients were dependent on total parenteral nutrition (TPN) for a mean of 31+/-2.7 months. The mean follow-up time from the date of evaluation was 9.2+/-0.9 months.

RESULTS

Eighty-two (32%) children underwent ITx with a mean waiting time of 10.1+/-1.3 months (simultaneous liver-intestinal allograft in 68% instances). Of the 175 patients who did not undergo transplantation, 120 died, 23 were lost to follow-up, and 32 are alive. Younger patients (< or =1 year) had poorer survival rates than patients older than 1 year (P<.0001). The patients with the worse prognosis were those with necrotizing enterocolitis, and those with the best prognosis were those with Hirschsprung's disease. Patients with "surgical" causes had poorer survival rates than those with "nonsurgical" causes (P<.04). Patients with bridging fibrosis or established cirrhosis had an earlier mortality than patients with portal fibrosis (P<.003). The worst survival rate was found for patients with bilirubin levels of greater than 3 mg/dL (P<.0001), plateletcounts less than 100.000/mL (P<.0001), prothrombin time greater than 15 seconds (P = .03) or partial thromboplastin time greater than 40 seconds (P<.04). Children who at the time of evaluation needed only an isolated intestinal allograft had a better prognosis than those who required a combined liver-intestine allograft (P<.00001). With multivariate analysis independent prognosis risk factors of poor outcome were hyperbilirubinemia and severity of histopathologic damage.

CONCLUSIONS

Early referral for ITx should occur before the development of liver dysfunction, taking into consideration the aforementioned risk factors that would facilitate the development and ominous evolution to liver failure.

The role of portosystemic shunting in children in the transplant era

PURPOSE

Variceal bleeding in children generally presents in the setting of cirrhosis but may also occur in the absence of liver disease and after successful liver transplantation. The authors reviewed their experience with portosystemic shunting in children to better define its efficacy in sclerotherapy failures, as primary therapy, and its role before and after liver transplantation.

METHODS

Between 1983 and 1997, 21 children with recurrent variceal bleeding underwent portosystemic shunting at the authors' institution. Patients were divided into two groups: 13 patients in group I presented with intrinsic liver disease (cirrhosis) as a cause for portal hypertension; eight patients in group II with no liver disease had extrahepatic portal venous thrombosis, five of which occured after successful liver transplantation. The mean age was 8.6 years (range, 3 to 18). Shunt procedures were semielective, and were performed successfully in all children without any operative morbidity or mortality. Follow-up ranged from 6 months to 15 years.

RESULTS

Shunt procedures included splenorenal (n = 15), splenocaval (n = 1), side-to-side splenorenal (n = 1), inferior mesenteric vein to renal vein (n = 1), mesocaval (n = 1), and transcutaneous intrahepatic portosystemic shunt (TIPS; n = 2). All patients in group II are alive and well with no further bleeding or occlusions. Of the 13 patients in group I, three had bleeding postshunt, and three patients went on to require liver transplantation because of worsening liver disease. One child died of liver failure with encephalopathy 4 years after shunting. There were two shunt occlusions.

CONCLUSIONS

Portosystemic shunting is effective therapy in patients with intrinsic liver disease, with salvage amenable by liver transplantation in the treatment failures. It is definitive therapy in patients with extrahepatic venous thrombosis.

Serial measurement of Epstein-Barr viral load in peripheral blood in pediatric liver transplant recipients during treatment for posttransplant lymphoproliferative disease

BACKGROUND

Few data are available describing the natural history of the Epstein-Barr virus (EBV) viral load after the diagnosis of EBV-associated posttransplant lymphoproliferative disease (PTLD). Accordingly, we prospectively followed the EBV viral load after the diagnosis of EBV/PTLD in seven pediatric orthotopic liver transplant recipients.

METHODS

EBV viral loads were serially measured by quantitative competitive polymerase chain reaction of the peripheral blood from pediatric patients with PTLD and correlated with the clinical course of these children. Viral loads >200 genome copies/10(5) peripheral blood lymphocytes were considered consistent with an increased risk of PTLD. Viral loads <200 obtained during treatment for PTLD were considered evidence of "clearance" of EBV; subsequent loads >200 were considered evidence of virologic "rebound."

RESULTS

The mean EBV viral load at the time of diagnosis of PTLD was 1029. All patients "cleared" their EBV viral load during the treatment of PTLD; patient and graft survival in this series was 100%. The mean time to clearance of EBV from the peripheral blood (18.8 days) was similar to the mean time to onset of first rejection (13.8 days). EBV viral load at the time of diagnosis of rejection after PTLD was always <100. A rebound in the EBV viral load to >200 was noted in five of seven patients a median of 3.5 months (range 2.3-13 months) after the diagnosis of EBV/PTLD. However, none of these children has had any evidence of PTLD recurrence.

CONCLUSIONS

Clearance of the EBV viral load from the peripheral blood seems to correlate with restoration of the host's immune response as noted both by the regression of the PTLD and the onset of rejection. Late rebound of the EBV viral load is common and does not seem to predict disease recurrence.

A technique for distal splenoadrenal shunting in pediatric portal hypertension

Technical modification of the DSRS by using the end-to-end splenoadrenal anastomosis allows for effective selective decompression of portal hypertension in children, can be accomplished with no perioperative mortality, and has demonstrated longterm patency and minimal morbidity. Clinical encephalopathy was seen in only 1 patient although 3 additional patients required lactulose therapy.

Management of posttransplant lymphoproliferative disease in pediatric liver transplant recipients receiving primary tacrolimus (FK506) therapy

BACKGROUND

Posttransplant lymphoproliferative disease (PTLD) after pediatric liver transplantation has been associated with high mortality rates.

METHODS

The present study examined 282 consecutive pediatric liver transplant recipients from October 1989 to June 1996 who received primary tacrolimus immunosuppression. The aim was to determine the incidence of PTLD, management strategies, and patient outcome.

RESULTS

The incidence of PTLD was 13% (361282) with a mean age of 5.5+/-0.7 years (range 0.6 to 15) at diagnosis. The average time from transplantation to PTLD was 10.1+/-2.1 months. Initial treatment of PTLD consisted of reduction (3 patients) or discontinuation (33 patients) of tacrolimus and initiation of antiviral therapy (intravenous ganciclovir, 14 patients; intravenous acyclovir, 22 patients; or both, 5 patients). Alpha-interferon was used in four patients (two successfully). One patient also received gamma-interferon, chemotherapy, and radiation for a central nervous system lesion. Chemotherapy was also used in one patient with Burkitt's, whereas one patient with a pulmonary lesion received additional radiation therapy. Three patients received supportive surgery for gastrointestinal involvement, and one patient had a splenectomy for hemolysis. Overall mortality was 22% (8/36) with 5 (14%) PTLD-related deaths (disseminated disease, 4 patients; bowel perforation, 1 patient). Of 31 survivors, 23 had acute rejection at a median time of 24 days after PTLD, with 2 patients developing chronic rejection. One patient required retransplantation. Present immunosuppression consists of tacrolimus monotherapy in 14 patients, tacrolimus/prednisone in 8 patients, and none in 6 patients.

CONCLUSION

In summary, PTLD can be successfully treated with reduction of immunosuppression and administration of antiviral agents in most patients. The management of rejection after PTLD requires reassessment of disease status and judicious reintroduction of immunosuppression therapy.

Weaning of immunosuppression in liver transplant recipients

Immunosuppression has been sporadically discontinued by noncompliant liver allograft recipients for whom an additional 4 1/2 years of follow-up is provided. These anecdotal observations prompted a previously reported prospective drug withdrawal program in 59 liver recipients. This prospective series has been increased to 95 patients whose weaning was begun between June 1992 and March 1996, 8.4+/-4.4 (SD) years after liver replacement. A further 4 1/2 years follow-up was obtained of the 5 self-weaned patients. The prospectively weaned recipients (93 livers; 2 liver/kidney) had undergone transplantation under immunosuppression based on azathioprine (AZA, through 1979), cyclosporine (CsA, 1980-1989), or tacrolimus (TAC, 1989-1994). In patients on CsA or TAC based cocktails, the adjunct drugs were weaned first in the early part of the trial. Since 1994, the T cell-directed drugs were weaned first. Three of the 5 original self-weaned recipients remain well after drug-free intervals of 14 to 17 years. A fourth patient died in a vehicular accident after 11 years off immunosuppression, and the fifth patient underwent retransplantation because of hepatitis C infection after 9 drug-free years; their allografts had no histopathologic evidence of rejection. Eighteen (19%) of the 95 patients in the prospective series have been drug free for from 10 months to 4.8 years. In the total group, 18 (19%) have had biopsy proved acute rejection; 7 (7%) had a presumed acute rejection without biopsy; 37 (39%) are still weaning; and 12 (13%, all well) were withdrawn from the protocol at reduced immunosuppression because of noncompliance (n=8), recurrent PBC (n=2), pregnancy (n=1), and renal failure necessitating kidney transplantation (n=1). No patients were formally diagnosed with chronic rejection, but 3 (3%) were placed back on preexisting immunosuppression or switched from cyclosporine (CsA) to tacrolimus (TAC) because of histopathologic evidence of duct injury. Two patients with normal liver function died during the trial, both from complications of prior chronic immunosuppression. No grafts suffered permanent functional impairment and only one patient developed temporary jaundice. Long surviving liver transplant recipients are systematically overimmunosuppressed. Consequently, drug weaning, whether incomplete or complete, is an important management strategy providing it is done slowly under careful physician surveillance. Complete weaning from CsA-based regimens has been difficult. Disease recurrence during drug withdrawal was documented in 2 of 13 patients with PBC and could be a risk with other autoimmune disorders.