Cinemicroscopy of Hyperacute Pulmonary Rejection

Abstract Rejection processes were studied in xenografts and allotransplants of cat or dog lungs to dogs. Cinemicroscopy of the microcirculation in untreated animals showed almost immediate sludging, cellular aggregation, reduced vascular caliber, diminished blood flow, and rapid development of perivascular edema. The principal mechanisms of the extremely rapid xenograft rejection include capillary and arteriolar obstruction due to cellular aggregation. Pretreatment with heparin was virtually valueless, while methylprednisolone offered temporary protection.