Polymerase chain reaction for diagnosis of herpetic intraocular inflammation.

The authors present a polymerase chain reaction method for rapid and direct diagnosis of herpetic intraocular infections using small volume samples of intraocular fluid from 29 patients with various intraocular inflammatory diseases and 24 controls with senile cataract. Of six patients with early acute retinal necrosis from whom aqueous humor was tested, four were found to be positive for the presence of varicella-zoster (VZV) DNA while the other two were positive for the presence of herpes simplex virus (HSV) DNA. One of the patients with HSV DNA had been tested at an extremely early stage, at which time the aqueous humor viral antibody ratio did not predict a specific viral infection. Among four patients with acute retinal necrosis in relatively late stages following treatment with acyclovir from whom vitreous was obtained and tested, only one was found to have the presence of any viral DNA (VZV). On the other hand, the vitreous viral antibody ratio was found to be predictive of VZV infection in all four cases. VZV DNA was also detected in aqueous humor samples from four patients with suspected herpes zoster anterior uveitis, while HSV DNA was found in the aqueous humor of one patient with nonspecific keratouveitis. Neither human cytomegalovirus DNA nor human herpesvirus-6 DNA was detected in any sample included in this study. Finally, Epstein-Barr virus DNA was detected in the aqueous humor of the majority of patients studied and identified in cataract patients as well, suggesting either low specificity of the authors' assay for this virus or ubiquity of this virus in human eyes. In summary, the PCR method proved to be a very useful tool in establishing an etiological diagnosis in patients in the early stages of acute retinal necrosis, and in patients with anterior uveitis due to suspected HSV or VZV infection.