Preformed antibiodies cause

Ref Robbins 9/e p233-234 Hyperacute Rejection Hyperacute rejection occurs within minutes to a few hours after transplantation in a presensitized host and typically is recognized by the surgeon just after the vascular anastomosis is completed. In contrast with a nonrejecting kidney graft, which regains a normal pink color and tissue turgor and promptly excretes urine, a hyperacutely rejecting kidney rapidly becomes cyanotic, mottled, and flaccid and may excrete only a few drops of bloody fluid. The histologic picture is characterized by widespread acute aeritis and aeriolitis, vessel thrombosis, and ischemic necrosis, all resulting from the binding of preformed antibodies to graft endothelium. Viually all aerioles and aeries exhibit char- acteristic acute fibrinoid necrosis of their walls, with narrow- ing or complete occlusion of the lumens by precipitated fibrin and cellular debris