Lymphoproliferation in children after liver transplantation

Prevention and treatment for Epstein-Barr virus infection and related cancers

Epstein-Barr virus (EBV) was the first herpes virus described as being oncogenic in humans. EBV infection is implicated in post-transplant lymphoproliferative diseases (PTLD) and several other cancers in non-immunocompromised patients, with more than 200,000 new cases per year. While prevention of PTLD is improving, mainly based on EBV monitoring and preemptive tapering of immunosuppression, early diagnosis remains the best current option for the other malignancies. Significant progress has been achieved in treatment, with decreased mortality and morbidity, but some challenges are still to face, especially for the more aggressive diseases. Possible prevention by EBV vaccination would be a more global approach of this public health problem, but further active research is needed before this goal could be reached.

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.

Phase I/II studies to evaluate safety and immunogenicity of a recombinant gp350 Epstein–Barr virus vaccine in healthy adults

Two double-blind randomised controlled studies (phase I and I/II) were performed to assess for the first time the safety and immunogenicity of a recombinant subunit gp350 Epstein-Barr virus (EBV) vaccine in 148 healthy adult volunteers. All candidate vaccine formulations had a good safety profile and were well tolerated, with the incidence of solicited and unsolicited symptoms within a clinically acceptable range. One serious adverse event was reported in the phase I trial which was considered to be of suspected relationship to vaccination. The gp350 vaccine formulations were immunogenic and induced gp350-specific antibody responses (including neutralising antibodies).

Pediatric liver transplantation

Liver transplantation has become the accepted standard of care in the treatment of a child with a failing liver. Advances in the management of critical care and immunosuppression along with the development of innovative operative procedures have improved outcome such that 5-year survival rates of 80% to 90% are expected following liver transplantation. Organ allocation schemes have evolved in an effort to better stratify recipient risk thereby more appropriately distributing deceased donor grafts. A persistent shortage of appropriate donors continues to contribute to patient mortality. The consequences of long-term immunosuppression have become increasingly apparent such that health care providers need to be aware of the side effects of chronic immunosuppression. New strategies need to be defined to minimize the need of continuous immunosuppression. The continued success of pediatric liver transplantation will require multi-disciplinary health care teams comprised of general pediatricians, pediatric hepatologists, transplant surgeons, and transplant coordinators who focus on the complex needs of the transplant recipient.

Post-transplantation lymphoproliferative disorders localizing to the gastrointestinal tract after liver transplantation: report of five pediatric cases

Post-transplantation lymphoproliferative disorder (PTLD) is a life-threatening complication of organ transplantation. PTLD can occur in every kind of organ transplantation. From July 1992 to July 2004, five patients were diagnosed at our transplantation center with PTLD after pediatric liver transplantation. During this period, there were 52 pediatric patients (<18 yr) receiving an orthotopic liver transplantation (OLT) at our center. All five patients had transmural gastrointestinal (GI) PTLD, which occurred mostly in the stomach and duodenum. Epstein-Barr virus (EBV) in situ was demonstrated in each case. EBV viral load was noted to be an important risk factor. Treatment included dose reduction of immunosuppressants and anti-CD20 antibody infusion. Chemotherapy, including cyclophosphamide, doxorubicin, vincristine, and prednisolone, was given to three patients. Four patients have survived more than 10 months until now after treatment. The one who was unresponsive to chemotherapy and anti-CD20 antibody had diffuse metastasis and died of systemic candidiasis. In our series, each PTLD involved the GI tract. The mechanism of this phenomenon is unclear, but these five cases indicate the high incidence of PTLD in pediatric solid organ transplantation.

Pediatric liver transplantation

In the past two decades, pediatric liver transplantation has become the state-of-the-art operation with anticipated success and limited mortality. The future success of pediatric liver transplantation will require thoughtful solutions to the delicate balance of risk to donors and recipients, the complex needs of the acute postoperative patient, and the long-term challenges of chronic immunosuppression in these previously unsalvageable patients.

Low-dose immunosuppression reduces the incidence of post-transplant lymphoproliferative disease in pediatric liver graft recipients

OBJECTIVES

In pediatric solid organ transplantation, the Epstein-Barr virus (EBV)-related lymphoproliferative disorders (PTLD) still play a major role in post-transplant morbidity and mortality. The aim of the study was to determine the incidence of PTLD in pediatric patients with liver transplant who receive low-dose immunosuppression protocols.

METHODS

All pediatric patients (n = 269) received a dual immunosuppression therapy consisting of cyclosporine A (initial trough levels, 170-200 microg/L; trough levels for maintenance immunosuppression after 1 year, 80-100 microg/L) and prednisolone (starting dose, 60 mg/m2). Steroids were reduced to 30 mg/m2 after 1 week, followed by a weekly tapering to 5 mg/m2. Seventy-seven of 269 patients were switched to tacrolimus therapy. The authors evaluated the significance of EBV-DNA monitoring by quantitative polymerase chain reaction in identifying patients at risk for PTLD.

RESULTS

Patient survival was 90.3%; graft survival was 85.9%. Eight patients lost their grafts because of chronic rejection. The incidence of PTLD was low (0.7%), although a significant EBV viral load was found in 42.4% of the patients. One third of the patients with a viral load of 3,000 genomes/10(5) cells or greater had clinical signs of EBV infection.

CONCLUSIONS

The authors conclude that low-dose immunosuppressive protocols significantly reduce the incidence of PTLD. In patients treated with that regimen, the monitoring of EBV viral load seems not to be helpful. It can be assumed that low-dose immunosuppression does not suppress EBV-specific cytotoxic CD8+ T cells, thus allowing the host to control EBV infection without the risk of PTLD. Our low-dose immunosuppression protocol did not increase the risk of chronic rejection.

Overview of pediatric liver transplantation

Liver transplantation is a successful and useful therapy for children with chronic or end-stage liver disease and those with a variety of extrahepatic metabolic diseases that can be corrected by liver replacement. Major developments in medical management, donor availability and procurement, operative techniques, and post-operative management all contributed to the dramatic improvement in outcome and growth of liver transplantation from its inception in 1963 [1,7,21]. The excellent long-term outcomes that have been achieved are the product of the coordinated efforts of liver transplant surgeons, specialists in pediatric hepatology and other medical areas, nurses, local practitioners, and the patients and their families. Future advances in transplant immunobiology, organ availability and infection control are likely to lead to still greater improvements in short and long-term outcome [34].