Abstract
Techniques have been developed for the transplantation of allografts of pure rabbit corneal epithelium and of endothelium with Descemet's membrane and only minimal amounts of adherent donor stroma. By appropriately inducing vascularization of the donor graft, the recipient becomes sensitized to and ultimately rejects the pure epithelial graft. The epithelium is rejected as a moving front of infiltrated and dying donor cells, loith the rapidly regenerating recipient epithelium effecting immediate repair of the defect. The entire epithelial rejection process takes place in the absence of persisting stromal edema and cloudiness. Sensitization by, and rejection of, pure corneal stromal allografts were also studied. Rejection is characterized by a diffuse band of leukocytic infiltrate which sweeps across the donor tissue, leaving dead keratocytes in its wake. Endothelial allografts also lead to sensitization of the recipient and to graft rejection, again when appropriate vascularization is induced. Like epithelium, the rejection of corneal endothelium is associated with an advancing front of densely infiltrated and dying cells. In this instance, however, repair of the defect by recipient endothelium is so slow that edema and cloudiness of the overlying stroma develop and persist for long periods of time. Endothelial regeneration in the rabbit is associated with substantial recovery of corneal clarity.