Virus particles and leukocytes in herpes simplex keratitis

Nine corneal specimens were obtained after penetrating keratoplasty for ultrastructural analysis. All the corneas had earlier suffered from herpetic infections and scarring. Six corneas presented vascularized interstitial keratitis and three corneas showed chronic keratitis. Five specimens with interstitial keratitis presented stromal herpes virus-like particles. All the corneas containing virus particles showed stromal lymphocytic infiltration, and in four, macrophages were present. In two cases, lymphocytes were in close contact with affected keratocytes, suggesting that cell-mediated immunity plays a role in herpetic interstitial keratitis. The corneas with disciform keratitis were free of virus particles and leukocytic infiltration. The observed ultrastructural findings suggest that retrocorneal ridges, a form of posterior corneal scarring, has its origin in a granulomatous reaction between the stroma and Descemet's membrane.