Immunocytologic localization of herpes simplex type 1 viral antigens in herpetic retinitis and encephalitis in an adult.

An immunoperoxidase technique was utilized to identify herpes simplex type I viral antigens in the retina, optic nerve and brain of an adult with herpetic retinitis and encephalitis. Viral antigens were demonstrated in all layers of retina, retinal pigment epithelium and to a lesser extent, in choroid. Oligodendroglia in the right optic nerve and neuronal and glial cells in the grey and white matter of the left frontal, inferior parietal and temporal lobes of the brain also expressed herpes simplex antigens. The sensitive immunoperoxidase method allowed detection of viral antigens in many cells without intranuclear inclusions or surrounding inflammation, and thereby added valuable information regarding the anatomic and cellular localization of herpetic infection. The clinicopathologic features that characterize herpes simplex retinitis in the adult are compared to cytomegalovirus retinopathy.