Erythropoietin Therapy to Induce Regulatory T Cells in Liver Transplant Recipients

This is a single-center, proof-of-concept study that will evaluate EPO in stable, liver transplant participants on immunosuppression monotherapy with Tacrolimus or Everoliumus to \\\[primary objective\]. Approximately 20 participants will be enrolled who are males or females aged 18 to 74 years with a history of liver transplantation performed more than two years ago for non-immune causes. They must be receiving a stable immunosuppressive monotherapy regimen (tacrolimus or everolimus) for at least three months before enrollment. Participants will receive a single dose of erythropoietin 10,000 IU. The study duration is 12 weeks. The primary outcome is to define EPO effects on Treg induction in liver transplant recpients in vivo. We will use flow cytometry to analyze the phenotype of peripheral blood monocluear cells (PBMC) collected before and 4 and 12 weeks after EPO administration. Data will be analyzed to extract changes in lympohocyte subset frequencies, including Tregs. Secondary outcome is to delineate the regulatory functional capabilities of EPO induced Tregs in liver transplant recipients, in vivo. We will determineTREG function at baseline and after treatment in both arms by suppression assays. Finally, we will confirm the safety of EPO in liver transplant recipients by monitoring CBC and liver parameters, as well as any clinical symptoms, at weeks 4 and 12 visits.