Immunosuppression, compliance, and tolerance after orthotopic liver transplantation: state of the art

Orthotopic liver transplantation is the treatment of choice for several otherwise irreversible forms of acute and chronic liver diseases. Early implemented immunosuppressant regimens have had disappointing results with high rejection rates. However, new drugs have reduced the daily immunosuppression requirements, thereby improving graft and patient survival as well as kidney function. Liver rejection is a T-cell-driven immune response and is the active target of immunosuppressive agents. Immunosuppressants can be divided into pharmacological or biological drugs: the gold standard is the calcineurin inhibitors, steroids, mycophenolate mofetil, and mechanistic target of rapamycin inhibitors. Compliance with these agents is essential, although they can increase the risk of infections and neoplastic diseases. In some patients, graft tolerance can be achieved. Graft tolerance is defined as the absence of acute and chronic rejection in a graft, with normal function and histology in an immunosuppression-free, fully immunocompetent host, usually as the final result of a successful attempt at immunosuppression withdrawal. The occurrence of immunosuppressive-related complications has led to new protocols aimed at protecting renal function and preventing de novo cancer and dysmetabolic syndrome. The backbone of immunosuppression remains calcineurin inhibitors in association with other drugs, mainly over the short-term period. To avoid rejection and the side effects on renal dysfunction, de novo cancer, and cardiovascular syndrome, optimal long-term immunosuppressive therapy should be tailored in liver transplant recipients.