What is the time frame for hyperacute transplant rejection?

• A. Minutes
• B. Days to weeks
• C. Months
• D. Years

Answer: (A)

Hyperacute transplant rejection occurs almost immediately after the transplantation of an organ, typically within minutes. This type of rejection is facilitated by pre-existing antibodies in the recipient's immune system that recognize the donor organ as foreign. These antibodies bind to the endothelial cells of the transplanted organ, leading to a rapid inflammatory response, thrombosis, and ultimately, the destruction of the graft. Understanding this immediate response is critical in transplantation medicine, as it underscores the importance of pre-transplant screening and cross-matching to prevent sensitization of the recipient to donor antigens. Other types of rejection occur over longer time frames: acute rejection typically manifests days to weeks post-transplant, while chronic rejection can take months to years to develop.