Advances in Liver Transplantation: where are we in the pursuit of transplantation tolerance?

• Published in: European journal of immunology Vol. 51; no. 10; pp. 2373 - 2386
• Main Authors: Safinia, Niloufar, Vaikunthanathan, Trishan, Lechler, Robert Ian, Sanchez‐Fueyo, Alberto, Lombardi, Giovanna
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01-10-2021; John Wiley and Sons Inc
• Subjects: Animals; Cell Communication - immunology; Cell survival; Cell therapy; Chimeric antigen receptors; Clinical Studies as Topic; Clinical trials; Clinical Trials as Topic; Combined Modality Therapy; Hepatocytes; Highlights; Humans; Immunological tolerance; Immunomodulation; Immunoregulation; Immunosuppression; immunosuppression withdrawal; Immunosuppressive agents; Immunotherapy; Liver; Liver - immunology; Liver - metabolism; Liver diseases; Liver Diseases - etiology; Liver Diseases - therapy; Liver transplantation; Liver Transplantation - adverse effects; Liver Transplantation - methods; Liver Transplantation - trends; Liver transplants; Lymphocytes T; Models, Animal; Morbidity; Organ Specificity - immunology; regulatory T cells; Review|Basic; T-Lymphocyte Subsets - immunology; T-Lymphocyte Subsets - metabolism; T-Lymphocytes, Regulatory - immunology; T-Lymphocytes, Regulatory - metabolism; tolerance; Toxicity; Transplantation Immunology; Transplantation Tolerance - immunology; regulatory T cells; liver transplantation; tolerance; immunotherapy; immunosuppression withdrawal
• ISSN: 0014-2980; 1521-4141; 1521-4141
• DOI: 10.1002/eji.202048875

Liver transplantation is the ultimate treatment option for end‐stage liver disease. Breakthroughs in surgical practice and immunosuppression have seen considerable advancements in survival after transplantation. However, the intricate management of immunosuppressive regimens, balancing desired immunological quiescence while minimizing toxicity has proven challenging. Diminishing improvements in long‐term morbidity and mortality have been inextricably linked with the protracted use of these medications. As such, there is now enormous interest to devise protocols that will allow us to minimize or completely withdraw immunosuppressants after transplantation. Immunosuppression withdrawal trials have proved the reality of tolerance following liver transplantation, however, without intervention will only occur after several years at the risk of potential cumulative immunosuppression‐related morbidity. Focus has now been directed at accelerating this phenomenon through tolerance‐inducing strategies. In this regard, efforts have seen the use of regulatory cell immunotherapy. Here we focus particularly on regulatory T cells, discussing preclinical data that propagated several clinical trials of adoptive cell therapy in liver transplantation. Furthermore, we describe efforts to further optimize the specificity and survival of regulatory cell therapy guided by concurrent immunomonitoring studies and the development of novel technologies including chimeric antigen receptors and co‐administration of low‐dose IL‐2.
Long‐term survival in liver transplantation remains suboptimal secondary to the use of toxic immunosuppressants. Here, we review tolerizing immunotherapy strategies centered around the use, optimization, and expansion of regulatory T cells.