Herpes simplex virus type 1 transcription is not detectable in quiescent human stromal keratitis by in situ...

The purpose of this study was to determine whether herpes simplex virus (HSV) transcripts are present in the corneas of patients with chronic herpetic stromal keratitis.

Corneal buttons from patients with a history of stromal keratitis, but no ongoing active disease, together with positive and negative control tissues, were analyzed by in situ hybridization using single-stranded RNA probes for all three classes of viral lytic cycle transcripts as well as for the latency-associated transcripts (LATs). Tissues also were screened for presence of HSV genomic DNA using the polymerase chain reaction (PCR).

HSV DNA was detected in 7 of 13 quiescent corneas by PCR, but no viral transcripts were detected in any of these corneas by in situ hybridization.

At the level of detection afforded by in situ hybridization, HSV persistent in scarred human corneas after stromal keratitis appears to be transcriptionally dormant. This contrasts with the situation in neurons of latently infected sensory ganglia, in which LATs are present at high levels.