Pathological features of antibody-mediated rejection

Area of Science:

• Transplantation immunology
• Vascular biology

Background:

• Antibody-mediated rejection (AMR) is increasingly recognized as a major cause of graft loss in organ transplantation and xenotransplantation.
• AMR contributes to hyperacute, acute, and chronic rejection of allografts and xenografts.
• AMR often shows poor response to conventional anti-rejection therapies.

Purpose of the Study:

• To review the role of microvascular injury in antibody-mediated rejection (AMR).
• To discuss the pathological features of AMR in allografts and xenografts.
• To highlight the contribution of endothelial cell activation and death to graft loss in AMR.

Main Methods:

• Review of existing literature on antibody-mediated rejection and microvascular injury.
• Analysis of histopathological findings in graft rejection.
• Discussion of immunological barriers in xenotransplantation.

Main Results:

• Microvascular injury is a hallmark of AMR across hyperacute, acute, and chronic rejection phases.
• Endothelial cell activation and death in microvasculature lead to capillary destruction, hemorrhage, and microthrombi.
• These processes contribute to fibrotic scarring and ultimate graft loss.

Conclusions:

• Antibody-mediated rejection, characterized by microvascular injury, is a critical factor in graft failure.
• Understanding endothelial cell dynamics in AMR is crucial for developing new therapeutic strategies.
• Histopathology remains essential for diagnosing AMR in both allotransplantation and xenotransplantation.