Intestinal transplantation: Significance of immune responses

Intestinal allografts, with many resident immune cells and as a destination for circulating lymphocytes of the recipient, appear to be the most challenging solid organ transplants. The high incidence of acute rejection and frequent reports of fatal graft-versus-host disease (GvHD) after intestinal transplantation call for more research to describe the molecular mechanisms involved in the immunopathogenesis of post-transplant complications to define new therapeutic targets. In addition, according to the rapid development of immunosuppressive agents, it is time to consider novel therapeutic approaches in managing treatment-refractory patients with rejection or severe GvHD. Herein, the main immunological challenges before and after intestinal transplant including, brain-dead donor inflammation, acute rejection, antibody-mediated, and chronic rejections, as well as GvHD have been described. Besides, the new immune-based therapies used in experimental and clinical settings to improve tolerance toward intestinal allograft, and cases of operational tolerance have been reviewed.