Liver Transplantation With Tregs at MGH

The researchers in this study plan to enroll 9 participants who will receive at least the target Treg product (arTreg-CSB) dose of 2.5 x 10\^6 cells. Participants who receive at least 1 x 10\^6 cells but \< 2.5 x 10\^6 cells as a result of low cell yield will be included in intent-to-treat (ITT) analysis. Participants who successfully withdraw from all immunosuppression will undergo a research biopsy at 52 weeks following drug discontinuation to determine whether they meet the primary efficacy outcome of operational tolerance. Participants determined to be operationally tolerant will be followed until 104 weeks following drug discontinuation and have a research biopsy at that time to confirm that they remain operationally tolerant. Participants who fail drug withdrawal after 52 weeks but before 104 weeks will be followed until week 104 or 12 weeks after resuming immunosuppression, whichever is longer. The research biopsy at week 104 will be optional for these participants. Participants who do not successfully withdraw from all immunosuppression will complete 104 weeks of High Intensity Safety Follow-up after failing immunosuppression withdrawal. \*\*\* IMPORTANT NOTICE: \*\*\* The National Institute of Allergy and Infectious Diseases and the Immune Tolerance Network do not recommend the discontinuation of immunosuppressive therapy for recipients of cell, organ, or tissue transplants outside of physician-directed, controlled clinical studies. Discontinuation of prescribed immunosuppressive therapy can result in serious health consequences and should only be performed in certain rare circumstances, upon the recommendation and with the guidance of your health care provider.