Immune tolerance induction: Vascularized composite allografts and solid organ transplants

Abstract

Introduction: Immune tolerance induction could solve problems associated with lifelong immunosuppression, necessary to avoid allograft rejection. Objectives: To review immunological aspects, clinical models used and results achieved and to compare the results with solid organ transplantation and vascularized composite allotransplants. Materials and methods: A literature review was made in the PubMed database, yielding 299 results. The bibliography of the articles was reviewed and the pertinent documents were consulted. Finally, 83 articles were selected. Results: There are central and peripheral mechanisms to maintain tolerance to self-produced antigens. In clinical practice, central tolerance has been widely used through strategies that involve bone marrow transplantation. Several clinical trials, mostly in kidney transplant patients, have shown promising but inconsistent results. Conclusions: Immunosuppression was successfully suspended in renal transplantation patients, while its use was reduced considerably in hand transplantation patients. Immunological chimerism seems to be essential to develop tolerance to allografts, so it is necessary to elaborate protocols to induce persistent mixed chimerism.