CONFOCAL MICROSCOPY OF CORNEAL GRAFT-REJECTION

Corneal allografts were transplanted into inflamed and vascularized gr aft beds in rabbit eyes. The grafts were examined every 4 days by slit -lamp biomicroscopy and scanning confocal microscopy. Confocal images were recorded with a video camera and computer enhanced in real-time. Layers of the cornea were visualized in serial optical sections parall el to the epithelium. In the third postoperative week, signs of graft rejection were observed; slit-lamp examination revealed a circumferent ial line of epithelial rejection, along with cloudiness and edema. Ves sels were observed growing into the graft. By confocal microscopy, inf iltrating cells were seen in the graft stroma. Foci of cells were espe cially pronounced around the sutures. Scattered leukocyte infiltrates were prominent at capillary terminals. There was an accompanying reduc tion in the stromal keratocyte density in the region of the infiltrate . Additionally, various degrees of fibrosis were noted around each sut ure and at the host-graft interface. Confocal microscopy may provide a valuable clinical tool for determining the earliest indicators of an antigraft immune response, and as an aid in the differential diagnosis of other inflammatory conditions of the cornea.