Sinha Sb

A New Look at Hyperacute Rejection

Abstract A new method of cinemicroscopy has been employed to observe the developing in vivo pathology of hyperacute pulmonary xenograft rejection. The rheological findings were substantiated by serial biopsies. In a cat-to-dog xenograft model employing both cat lungs as a tissue block or with infusion of dog blood or plasma into the cat lung, there was rapid rejection. This was characterized by immediate erythrocyte aggregation, impaction of these aggregates into the pulmonary capillaries with cessation of blood flow, and, after only 15 minutes, a fully developed picture of massive capillary engorgement, atelectasis, and interstitial and intraalveolar edema and hemorrhage. Administration of heparin did not alter this process, and neither platelets nor polymorphonuclear leukocytes were prominent in the erythrocyte aggregates. Repeated exposure of the dog plasma to cat erythrocytes before infusion was effective in blocking this pulmonary rejection phenomenon.

Radiological dissociation of alveolar and vascular phases of rejection in allografted lungs.

Abstract Twelve dogs with allografted lungs were treated with azathioprine and rabbit antidog thymocyte serum. Chest roentgenography, pulmonary angiography, and lung biopsy revealed a dissociation of the alveolar and vascular components of rejection in 7 of the animals. The vascular phase of rejection was more effectively suppressed than the alveolar phase. This dissociation may produce a functional disturbance with a decreased ventilation to perfusion ratio within the allograft such as has been observed in human lung transplant recipients. The results of this investigation suggest that rejection plays a more important role than previously recognized in the ventilation-perfusion imbalance that occurs with pulmonary allografts.