An electron microscopic study of the mode of donor cell death in unmodified rejection of pig liver allografts.

The only type of cell death found in pig liver allografts 1 week after technically successful operation was apoptosis. Its extent paralleled the degree of mononuclear cell infiltration of the liver parenchyma, and mononuclear cells were found applied to the surfaces of hepatocytes showing early stages of the process. The results suggest that cellular immune attack induces apoptosis of donor cells, and that the action is a direct one. However, implication of other factors such as vascular damage in the induction of apoptosis in the grafts could not be excluded.