Pulmonary function of haplotype-matched and mismatched allografts in dogs treated with total-body irradiation, autologous marrow transplantation, methotrexate, and donor blood.

Seven beagle recipients surviving 2-11 years after allotransplantation of a left lung were available for study of pulmonary function. Significant reductions of ventilation and perfusion to the transplanted lung were documented by radionuclide scanning. These reductions in function were well-matched, however, and allowed relatively normal gas exchange, as measured by VD/VT, arterial PO2 and shunt fraction. The vasoconstrictor response of the transplanted lung to both hypoxia and stellate ganglion stimulation was comparable to that of the native lung. An abnormal rise in graft pulmonary vascular resistance and fall in PaO2 when the normal lung was made hypoxic suggest an inability of the transplanted lung to vasodilate and recruit blood vessels normally in response to increased blood flow. The animals were sacrificed at the conclusion of the pulmonary function testing. Pathologic study of the transplanted lungs showed minimal changes of rejection in spite of the fact that these recipient animals received no immunotherapy after the second posttransplant week.