Inducción de tolerancia inmunológica: alotrasplantes compuestos vascularizados y trasplantes de órgano sólido / Immune tolerance induction: vascularized composite allografts and solid organ transplants

Resumen Introducción. La inducción de tolerancia inmunológica solucionaría los problemas asociados con la inmunosupresión de por vida, necesaria para evitar el rechazo de aloinjertos. Objetivos. Revisar aspectos inmunológicos, modelos clínicos utilizados y resultados obtenidos en la tolerancia y comparar los resultados obtenidos con trasplante de órgano sólido y alotrasplante compuesto vascularizado. Materiales y métodos. Se realizó una búsqueda en la base de datos PubMed que arrojó 299 resultados; se revisaron las bibliografías de los artículos y se consultaron las referencias pertinentes. Al final se seleccionaron 83 artículos. Resultados. Existen mecanismos centrales y periféricos para mantener la tolerancia a antígenos propios; en la práctica clínica, la tolerancia central ha sido más utilizada, esto se ha hecho mediante estrategias que utilizan trasplante conjunto de medula ósea. Varios ensayos clínicos, la mayoría en pacientes con trasplante renal, han mostrado resultados prometedores pero inconsistentes. Conclusiones. En trasplantes renales fue posible suspender de forma exitosa la inmunosupresión, mientras que en trasplantes de mano se logró disminuirla considerablemente. El quimerismo inmunológico parece ser indispensable para el desarrollo de tolerancia a aloinjertos, por lo que es necesario desarrollar protocolos para inducir quimerismo mixto persistente.

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.

Surgical-allogeneic facial reconstruction: facial transplants.

Several factors including cancer, malformations and traumas may cause large facial mutilation. These functional and aesthetic deformities negatively affect the psychological perspectives and quality of life of the mutilated patient. Conventional treatments are prone to fail aesthetically and functionally. The recent introduction of the composite tissue allotransplantation (CTA), which uses transplanted facial tissues of healthy donors to recover the damaged or non-existent facial tissue of mutilated patients, resulted in greater clinical results. Therefore, the present study aims to conduct a literature review on the relevance and effectiveness of facial transplants in mutilated subjects. It was observed that the facial transplants recovered both the aesthetics and function of these patients and consequently improved their quality of life.