Intestinal Transplantation. A procedure still in development. Advances in Immunomodulation

The large mass of foreign lymphoid tissue transferred to the host with intestinal transplantation (IT) increases the risk of rejection and requires higher levels of immunosuppression compared to other solid organ transplants (SOT), and consequently, impacting the outcome negatively. Operational tolerance (OT), characterized by stable graft function in the absence of immunosuppression in an immunocompetent individual, is the desired but unattained “Holy Grail” for all SOT. However, there are examples in nature, and clinical observations of spontaneous OT, or occurring after an unexpected event which suggest the possibility of achieving OT through sophisticated therapeutic approaches. These approaches can be very diverse but are encompassed under the generic term immunomodulation, which refers to the set of therapies aimed at producing changes in the host’s immune system, with the aim of activating or weakening it. In this paper, we discuss the various immunomodulation strategies, whether already implemented or in different stages of development, and, for the sake of clarity, we have categorized them into four groups: 1. Advances in immunosuppression; 2. Tolerance induction through cell therapies; 3. Non-cellular therapies; and 4. Interventions on the donor or donor organs. These strategies can be applied to all SOT, but they are most needed in the IT, being children undergoing transplantation, due to their longer life expectancy, those who will benefit the most.