4111 Corneal transplantation causes recurrent herpes simplex in rats

&gg2g To study HSV reactivation end recurrent disease after comeal transplantation in rats. Methods Female PVG rats were inoculated on the comea with HSV-1 McKrae. At least 4 weeks after inoculation. they received either allogeneic (DA or LEW) or syngeneic corneel grafts end were exemined for stgns of recurrent HSV disease for up lo 30 days. m All allografts wara rejactad. Virus was shed in the tear Slm of 4/3B rats (11%) receiving allografts and 7/55 rats (13%) receiving syngeneic grafts. This was comparable to that efler UV-irradiation of the cornea, a known stimulus of recurrent disease. Characteristic epttheliel lesions were seen on me recipient wmea of 3 animals. One syngeneic graft became completely opaque. Neither removal of sutures nor rejectton provoked recurrent disease. Histological examination of 4 eyes thel shed virus revealed HSV antigens in all at the graft host junctiw. HSV-expressing cells were numerous in the stroma and extended to the endothelium. infiltrating cells in diseased areas were mainly HIS48’ granulocytes end many expressed HSV antigens. Conclusions Surgical trauma appears to be the most potent stimulus of recurrent disease after transplantation. Virus occasionally recurs in the recipient epithelium. but does not penetrate the basement membrane to the stroma. The graft-host junction appears to be a ‘weak spot’ where antigen readily reaches the strome. perhaps from nerve endings severed in the operation. Infiltrating cells then act as a conduit to the endothelium, which may become infected end prejudtt the graft