QUANTITATION OF HERPES-SIMPLEX VIRUS-DNA IN CEREBROSPINAL-FLUID OF PATIENTS WITH HERPES-SIMPLEX ENCEPHALITIS BY THE POLYMERASE CHAIN-REACTION

Background: Previous studies have shown the diagnostic utility of qual itative detection of herpes simplex virus (HSV) DNA by the polymerase chain reaction (PCR) in cerebrospinal fluid samples (CSF) from patient s with herpes simplex encephalitis (HSE). Objectives: To determine whe ther quantitation of HSV DNA in CSF could be useful for monitoring eff icacy of antiviral therapy and provide prognostic indications. Study d esign: A quantitative PCR assay using an internal control for evaluati on of PCR efficiency and detection of PCR inhibitors was developed and used for retrospective testing of 98 CSF samples from 26 patients wit h serologically diagnosed HSE during the period 1980-1995. Results: HS V DNA was detected in 36 CSF samples from 23 patients. PCR positivity was 100% for CSF samples collected within 10 days after onset, and 30. 4 and 18.7% for samples collected 11-20 and 21-40 days later, respecti vely. The 3 PCR-negative patients had their first CSF collected 14, 16 , and 28 days after onset, respectively. Three of 98 (3.1%) CSF sample s were completely or partially inhibitory to PCR. Initial DNA levels w ere not significantly different in patients with HSE due to either pri mary or recurrent HSV infection. In addition, they were not related to severity of clinical symptoms nor were predictive of the outcome. A p rogressive decrease in viral DNA levels was observed both in patients who received acyclovir therapy and in a small number of untreated pati ents. Conclusions: This study: (i) confirms the high sensitivity of PC R for the diagnosis of HSE; (ii) emphasizes the need for an internal c ontrol of amplification to achieve maximal sensitivity and perform rel iable quantitation of viral DNA; and (iii) suggests that CSF might not be the best specimen to investigate in studies of the natural history of HSE. (C) 1997 Elsevier Science B.V.