Investigation of herpes simplex virus type-1 latency in corneas

The recurrent rate of herpes simplex keratitis (HSK) was 4.17% after penetrating keratoplasty (PKP) was performed in 216 patients with HSK; the mean period of follow-up was 6.5 years. Immunohistochemical technique showed that HSV-1 antigens were present in the corneal stroma of rabbit eyes up to 45 days after primary corneal infection had subsided. No positive staining of HSV antigen was found in the sections of 18 human corneal buttons with quiescent herpetic lesions. However, after cocultured with primary rabbit kidney (PRK) cells, positive staining was noted in 6/9 human corneal buttons, and some PRK cells developed cytopathic effect. The detection of the sensitivity of cultured corneal cells to HSV-1 infection demonstrated that keratocytes were the most sensitive cells. These results suggest that the cornea may be another site of HSV-1 latency in addition to the trigeminal ganglion.