Alveolar lavage cytology in transplanted lungs. I. Staining methods and findings in dogs with autografts and allografts without immunosuppression

Alveolar lavages were performed repetitively on the normal and transplanted lungs of dogs that had received autografts or allografts without immunosuppression. One half of the lavage returns was fixed as a cytologic smear; the other half was subjected to semi thin section or electron microscopic examination. Of the staining methods used, the periodic acid Schiff (PAS) and Giemsa techniques were best for differentiating and counting cells. The Ladewig technique was best for evaluating the presence and location of fibrin. After autotransplantation, the proportion of so called alveolar macrophages increased, reached a peak in 4 to 7 days and then returned to normal. Phagocytized fibrin increased for the first postoperative wk, but no extracellular fibrin was ever observed. After allotransplantation, a progressive decrease in the proportion, size and vacuolization of so called alveolar macrophages was noted along with an increase in extracellular fibrin. Intracellular fibrin could be detected only up to the third day. These findings define adequate methods for preparing and staining material obtained from diagnostic alveolar lavages, and they suggest that the procedure may serve as an index of lung allograft rejection.