20-year survival post-liver transplant: much more is needed!

Therapy with regulatory T-cell infusion in autoimmune diseases and organ transplantation: A review of the strengths and limitations

In the last decade, cell therapies have revolutionized the treatment of some diseases, earning the definition of being the "third pillar" of therapeutics. In particular, the infusion of regulatory T cells (Tregs) is explored for the prevention and control of autoimmune reactions and acute/chronic allograft rejection. Such an approach represents a promising new treatment for autoimmune diseases to recover an immunotolerance against autoantigens, and to prevent an immune response to alloantigens. The efficacy of the in vitro expanded polyclonal and antigen-specific Treg infusion in the treatment of a large number of autoimmune diseases has been extensively demonstrated in mouse models. Similarly, experimental work documented the efficacy of Treg infusions to prevent acute and chronic allograft rejections. The Treg therapy has shown encouraging results in the control of type 1 diabetes (T1D) as well as Crohn's disease, systemic lupus erythematosus, autoimmune hepatitis and delaying graft rejection in clinical trials. However, the best method for Treg expansion and the advantages and pitfalls with the different types of Tregs are not fully understood in terms of how these therapeutic treatments can be applied in the clinical setting. This review provides an up-to-date overview of Treg infusion-based treatments in autoimmune diseases and allograft transplantation, the current technical challenges, and the highlights and disadvantages of this therapeutic approaches."

Past, Present, and Future of Regulatory T Cell Therapy in Transplantation and Autoimmunity

Regulatory T cells (Tregs) are important for the induction and maintenance of peripheral tolerance therefore, they are key in preventing excessive immune responses and autoimmunity. In the last decades, several reports have been focussed on understanding the biology of Tregs and their mechanisms of action. Preclinical studies have demonstrated the ability of Tregs to delay/prevent graft rejection and to control autoimmune responses following adoptive transfer in vivo. Due to these promising results, Tregs have been extensively studied as a potential new tool for the prevention of graft rejection and/or the treatment of autoimmune diseases. Currently, solid organ transplantation remains the treatment of choice for end-stage organ failure. However, chronic rejection and the ensuing side effects of immunosuppressants represent the main limiting factors for organ acceptance and patient survival. Autoimmune disorders are chronic diseases caused by the breakdown of tolerance against self-antigens. This is triggered either by a numerical or functional Treg defect, or by the resistance of effector T cells to suppression. In this scenario, patients receiving high doses of immunosuppressant are left susceptible to life-threatening opportunistic infections and have increased risk of malignancies. In the last 10 years, a few phase I clinical trials aiming to investigate safety and feasibility of Treg-based therapy have been completed and published, whilst an increasing numbers of trials are still ongoing. The first results showed safety and feasibility of Treg therapy and phase II clinical trials are already enrolling. In this review, we describe our understanding of Tregs focussing primarily on their ontogenesis, mechanisms of action and methods used in the clinic for isolation and expansion. Furthermore, we will describe the ongoing studies and the results from the first clinical trials with Tregs in the setting of solid organ transplantation and autoimmune disorders. Finally, we will discuss strategies to further improve the success of Treg therapy.

Twenty-year survival post-liver transplant: challenges and lessons

There have been numerous reports on survival outcomes after liver transplantation with short-term and mid-term follow-up. However, only a few reports are available for 20-year long-term survivors after liver transplantation. In Korea, the first successful deceased donor liver transplantation (DDLT) in a 13-year-old Wilson's disease patient was performed in 1988, and the first successful living donor liver transplantation (LDLT) in 9-month biliary atresia patient was performed in 1994. Because of the severe shortage of deceased donors and delayed launching of LDLT from December 1994, only 38 cases of liver transplantation (two pediatric LDLTs and 36 DDLTs) from 1988 to 1994 were included in this study (Strong and Fawcett, Hepatol Int 2015 [1]. doi: 10.1007/s12072-015-9617-1) to investigate more than 20-year survivors. Six adult recipients after DDLT and three pediatric recipients (one DDLT, two LDLTs) are alive now with normal liver function in Korea. Twenty-year survivors after DDLT and LDLT do not show that significant co-morbidities related to long-term immunosuppression and high-dose indefinite HBIG monotherapy has shown the reliable modality to prevent HBV-reinfection for HBV-related liver transplant candidates.