Chronic Rejection of Cardiac Allografts Is Associated With Increased Lymphatic Flow and Cellular Trafficking

Cardiac transplantation is an excellent treatment for end-stage heart disease. However, rejection of the donor graft, in particular, by chronic rejection leading to cardiac allograft vasculopathy, remains a major cause of graft loss. The lymphatic system plays a crucial role in the alloimmune response, facilitating trafficking of antigen-presenting cells to draining lymph nodes. The encounter of antigen-presenting cells with T lymphocytes in secondary lymphoid organs is essential for the initiation of alloimmunity. Donor lymphatic vessels are not anastomosed to that of the recipient during transplantation. The pathophysiology of lymphatic disruption is unknown, and whether this disruption enhances or hinders the alloimmune responses is unclear. Although histological analysis of lymphatic vessels in donor grafts can yield information on the structure of the lymphatics, the function following cardiac transplantation is poorly understood.