Recurrent herpes simplex keratitis with concurrent epithelial and stromal involvement. Immunohistochemical and ultrastructural observations.

A 65-year-old man with recurrent herpetic keratitis underwent corneal transplantation for persistent nonimmunologic graft failure. Histopathologic examination of the corneal button revealed an epithelial dendrite containing Cowdry type A inclusion bodies, moderate stromal edema, and a retrocorneal fibrous membrane. Immunohistochemical studies demonstrated herpes simplex virus antigens in epithelial cells bordering the dendritic defect and in stromal keratocytes. The mean width of corneal epithelium displaying herpes simplex virus-positive epithelial cells on either side of the dendritic defect measured 200 +/- 46 microns. By electron microscopy, herpesvirus particles were identified in epithelial cells lining the dendrite as well as in stromal keratocytes. Infected keratocytes were scattered throughout the stroma but were not observed subjacent to the epithelial dendrite. This study demonstrates that a recurrent epithelial dendrite can be associated with subclinical stromal infection of the graft.