Perfusatory recovery of the grafted lung during convalescence from acute rejection

The aim of this study was to evaluate whether or not perfusatory recovery o f the grafted lung occurs is the early stage of convalesce from acute rejec tion following a single lung transplantation. Eight adult mongrel dogs unde rwent an allotransplantation of the left lung with treatment of 10 mg/kg cy closporine and 4 mg/kg azathioprine. Doppler flow probes were placed to the ascending aorta and the left pulmonary artery. Immunosuppressant therapy w as discontinued to induce rejection after postoperative day 14. When the le ft pulmonary artery flow rate (l-PAFR) decreased to less than 20%, methylpr ednisolone (20 mg/kg) was administered for 3 days along with a resumption o f cyclosporine and azathioprine. Pulmonary circulation and chest roentgenog rams were evaluated every day through the rejection episode. An open lung b iopsy was also performed in each dog to obtain specimens of the grafts and native lungs for histologic examination. When l-PAFR decreased to less than 20%, mild acute rejection was found in all dogs. l-PAFR increased signific antly on the third day after methylprednisolone treatment. Thereafter, a hi stologic examination revealed minimal acute rejection in one dog and no abn ormality in seven dogs. The perfusatory recovery of the grafted lung was th ought to reflect the histological change in the course of convalescence.