Hyperacute rejection occurs within:?

Ans. (a) 12 hours(Ref: Robbins 9th ed p 233)Hyperacute rejection occurs when preformed antidonor antibodies are present in the circulation of the recipient. This form of rejection occurs within minutes or hours after transplantation. A hyperacutely rejecting kidney rapidly becomes cyanotic, mottled, and flaccid, and may excrete a mere few drops of bloody urine. Immunoglobulin and complement are deposited in the vessel wall, causing endothelial injury and fibrin-platelet thrombi.