Absence of herpesvirus DNA by polymerase chain reaction in ocular fluids obtained from immunocompetent patients

Objective: To assess the prevalence of herpesvirus DNA in ocular fluids obtained from healthy patients undergoing vitreoretinal surgery. Background: Polymerase chain reaction (PCR) has been used to detect herpesvirus DNA in patients with acute retinal necrosis and cytomegalovirus retinitis. Little is known regarding the prevalence of detectable herpesvirus DNA in ocular fluids collected from healthy seropositive patients with no clinical evidence of viral retinitis. Methods: Seventy-five intraocular specimens (35 aqueous and 40 vitreous samples) were collected from 75 patients undergoing scleral buckling or vitrectomy. Using a PCR-based assay, the authors tested each specimen for the presence of herpesvirus genome DNA with primers specific for cytomegalovirus, Epstein-Barr virus, herpes simplex virus types 1 and 2, and varicella tester virus. Serologic testing for immunoglobulin G (IgG) and IgM levels corresponding to each of the herpesviruses was also performed. Results: Of the 75 samples tested, none was found to harbor herpesvirus DNA. The assay did not give false-positive results in patients with active intraocular inflammation. The sensitivity of the assay was 0.08 infection-forming units for cytomegalovinrs, 0.6 tissue culture infectious doses for herpes simplex virus, 0.5 infected-cell equivalents for Epstein-Barr virus, and 0.03 focus-forming units for varicella tester virus. The percentage of patients with positive herpesvirus serology ranged from 86% to 100% and was consistent with rates observed in the general population. Conclusions: The prevalence of herpesvirus DNA detectable by PCR techniques in ocular fluids appears to be quite low despite the high proportion of patients who tested positive for herpesvirus antibodies. Therefore, a positive result obtained in a patient presenting with vitreoretinal inflammation should be regarded as significant.