Quantitative analysis of herpes simplex virus DNA in cerebrospinal fluid of children with herpes simplex encephalitis.

Herpes simplex virus (HSV) DNA in the cerebrospinal fluid (CSF) of children with herpes simplex encephalitis (HSE) was quantified and typed using the polymerase chain reaction (PCR) assay. During the acute phase, HSV-DNA was detected in the CSF of 13 patients with HSE, including 5 neonates. A restriction profile of the PCR products cleaved with the restriction enzymes XhoI and BglII showed that 2 neonatal samples were HSV-2, and the remainder were HSV-1. The amount of HSV-DNA in the initial CSF ranged from 10(2)-10(5) copies/ml. A significantly greater number of HSV-DNA copies was detected in neonates than in older children (mean 3.9 vs. 2.5, log 10 copies/ml p < .05). Except for one patient, the amount of HSV-DNA decreased gradually with acyclovir therapy. These results show that a quantitative PCR assay is applicable not only to the diagnosis of HSE but also for monitoring the response to antiviral drugs.