Everolimus Rescue Treatment for Chronic Rejection After Pediatric Living Donor Liver Transplantation: 2 Case Reports

The New Challenge in Pediatric Liver Transplantation: Chronic Antibody-Mediated Rejection

Antibody-mediated rejection (AMR) of liver allograft transplantation was considered as anecdotal for many decades. However recently, AMR has gained clinical awareness as a potential cause of chronic liver injury, leading to liver allograft fibrosis and eventual graft failure. (1) Methods: Literature on chronic AMR (cAMR) in pediatric post-liver transplant patients was reviewed for epidemiologic data, physiopathology, diagnosis, and treatment approaches. (2) Results: Accurate incidence of cAMR in pediatric liver transplantation remains unknown. Diagnostic criteria of cAMR were suggested by the Banff Working Group in 2016 and are based on standardized histopathological findings, C4d staining pattern, associated with the presence of donor-specific antibodies (DSA). Physio-pathological mechanisms are not clear for the technically difficult-to-obtain animal models reproducing cAMR. Treatment protocols are not established, being limited to case reports and case series, based on experience in ABO incompatible transplantation and kidney transplantation. Immunosuppression compliance with adequate dose adjustment may prevent cAMR. Conversion of Cyclosporine to Tacrolimus may improve pathological findings if treated in early phase. The association of steroids, Mycophenolate Mofetil (MMF) and mTOR inhibitors have shown some synergistic effects. Second-line treatments such as intravenous immunoglobulin (IVIG) and plasma exchange may decrease antibody titers based on ABO incompatible transplant protocols. The use of anti-CD20 (Rituximab) and proteasome inhibitors (Bortezomib) is controversial due to the lack of qualified studies. Therefore, multicenter randomized trials are needed to establish the best therapeutic strategy. In refractory cases, re-transplantation is the only treatment for allograft failure. (3) Conclusions: This literature review collects recent clinical, histopathological, and therapeutical advances of cAMR in liver allograft transplantation of pediatric patients. There are many physio-pathological aspects of cAMR to be clarified. Further efforts with multicenter prospective protocols to manage patients with cAMR are needed to improve its outcome.

Safety and Efficacy of Everolimus Rescue Treatment After Pediatric Living Donor Liver Transplantation

PURPOSE

Everolimus (EVR) is a derivative of sirolimus with a similar mechanism of action. The safety and efficacy of EVR after pediatric living donor liver transplantation (LDLT) are currently unknown. The purpose of this study was to examine the safety and efficacy of EVR as rescue therapy after pediatric LDLT.

METHODS

This study included patients younger than 19 years of age who received EVR after LDLT at our institution. EVR was administered as rescue treatment in addition to tacrolimus. In 21 patients, EVR dose, trough level, outcomes, and adverse effects were assessed.

RESULTS

Original diseases of patients consisted of biliary atresia (n = 11), Alagille syndrome (n = 3), fulminant hepatitis (n = 3), hepatoblastoma (n = 2), and other (n = 2). Mean age at transplant was 2.0 years (range 0.6-6.2 years). Mean age at initial EVR administration was 8.0 years (range 0.9-18.9 years). Indications for EVR use were graft fibrosis (n = 8), refractory acute cellular rejection (n = 5), renal sparing (n = 4), hepatoblastoma (n = 2), and chronic rejection (CR) (n = 2). Mean duration of administration was 17.1 months (range 2.1-60.4 months). Mean dose was 0.5 mg/m² twice daily. Mean EVR trough level was 2.5 ng/mL (range 1.5-5.0 ng/mL). Liver function improved and fibrosis did not progress in all patients with CR. However, 14 patients (67%) experienced adverse effects that required EVR dose reduction or discontinuation.

CONCLUSION

EVR is tolerable for pediatric patients after LDLT with dose adjustment. EVR had a certain effect to relieve progression on CR. Further follow-up is required.

Effect of everolimus rescue therapy for acute cellular rejection following pediatric living donor liver transplantation: Report of one case

Acute cellular rejection (ACR) after pediatric living donor liver transplantation (LDLT) is often curable with steroid pulse therapy, but a few pediatric patients show steroid-resistant ACR, which is difficult to control. We report the effect of everolimus as a rescue therapy for ACR in a case of pediatric LDLT. The patient was a 11-year-old girl who was admitted due to subacute liver failure of unknown cause. LDLT operation using a modified right liver graft from her mother was performed. The graft-recipient weight ratio was 1.30. The explant liver showed massive hepatic necrosis. The patient recovered uneventfully with immunosuppression using tacrolimus and low-dose steroid. However, at postoperative day (POD) 20, the liver enzyme levels began to increase. The first liver biopsy taken at POD 25 showed moderate ACR with rejection activity index (RAI) score of 7. At that time, steroid pulse therapy was performed, but the patient did not respond and the liver enzyme levels increased further. The second liver biopsy taken at POD 40 showed moderate ACR with RAI score of 7. At this time, everolimus was administered, and soon after that, liver enzyme levels had gradually improved. Currently, the patient is doing well for 44 months to date without any abnormal findings. The maintenance target trough concentrations were tacrolimus 5 ng/ml and everolimus 3 ng/ml. Our case demonstrated the effect of rescue therapy using everolimus for ACR following pediatric LDLT. Further studies are needed to assess the role of everolimus in pediatric liver transplant recipients suffering from ACR.