hyperacute rejection

This form of rejection occurs within minutes or hours after transplantation and can sometimes be recognized by the surgeon just after the graft vasculature is anastomosed to the recipient’s.

In contrast to the nonrejecting kidney graft, which rapidly regains a normal pink coloration and normal tissue turgor and promptly excretes urine, 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, and electron microscopy discloses early endothelial injury together with fibrin-platelet thrombi.

There is also a rapid accumulation of neutrophils within arterioles, glomeruli, and peritubular capillaries. These early lesions point to an antigen-antibody reaction at the level of vascular endothelium.

Subsequently, these changes become diffuse and intense, the glomeruli undergo thrombotic occlusion of the capillaries, and fibrinoid necrosis occurs in arterial walls. The kidney cortex then undergoes outright infarction (necrosis), and such nonfunctioning kidneys have to be removed.