Patterns of vascular damage in the antibody-mediated rejection of skin xenografts in the mouse.

Established rat skin grafts carried by immunosuppressed mice were acutely destroyed by an intravenous administration of mouse antirat lymphocyte serum. The histologic pattern of destruction was dependent on the amount of antiserum administered. At low doses (0.01 ml) an Arthus-like reaction was seen with early accumulation of granulocytes. At high doses (0.25 ml) a Shwartzman-like pattern occurred, with early intravascular thrombosis and without evident participation of granulocytes in the initial phases. Groups of mice that received intermediate doses showed graft changes that were transitional between these two types of destruction. Similar histologic patterns have been described in clinical transplantation. Our results show that they are not fundamentally different and that the severity of the triggering reaction determines which of either type will occur.