Acute Transplant Rejection

Acute transplant rejection is a condition where the body's immune system attacks a newly transplanted organ, such as a kidney, heart, or liver. This happens because the immune system recognizes the transplanted organ as foreign and tries to destroy it. The main body system involved is the immune system, which can cause inflammation and damage to the transplanted organ. Symptoms may include fever, pain over the transplant site, and decreased function of the transplanted organ. If not treated promptly, this rejection can lead to organ failure. Monitoring and early detection are important to protect the health of the transplant recipient. The condition highlights the challenge of balancing immune defense with acceptance of the new organ.

Acute transplant rejection is an immune-mediated process occurring within weeks to months after organ transplantation, characterized by a cellular immune response against donor antigens. It is primarily caused by recipient T lymphocytes recognizing donor major histocompatibility complex (MHC) molecules as foreign, leading to infiltration of the graft by activated CD8+ cytotoxic T cells and CD4+ helper T cells. This results in inflammation, endothelial injury, and parenchymal damage of the transplanted organ. Acute rejection is a major cause of early graft dysfunction and can significantly impact graft survival if untreated. It is distinct from hyperacute rejection, which occurs minutes to hours post-transplant, and chronic rejection, which develops over months to years. Immunosuppressive therapy aims to prevent or reverse this process by inhibiting T cell activation and proliferation.