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August 1997

Presence of Herpes Simplex DNA in Surgical Tissue From Human Epileptic Seizure Foci Detected by Polymerase Chain Reaction: Preliminary Study

Author Affiliations

From the Departments of Neurology (Drs Sanders, Conrad, Schmid, Kaufman, Walsh, and De Salles) and Surgery (Dr De Salles) and the Brain Research Institute (Drs Conrad, Schmid, and Tourtellotte), the University of California, Los Angeles School of Medicine; the Neurology and Research Services, West Los Angeles Veterans Affairs Medical Center (Mr Felisan and Ms Waddell); and the California Comprehensive Epilepsy Program, (Drs Swartz, Kaufman, Walsh, and De Salles) Los Angeles. Dr Sanders is now with the Division of Neuropathology, Presbyterian University Hospital, University of Pittsburgh Medical Center, Pittsburgh, Pa.

Arch Neurol. 1997;54(8):954-960. doi:10.1001/archneur.1997.00550200020005

Objectives:  To determine whether herpes simplex virus causes monofocal epilepsy and to assess the presence of herpes simplex virus 1 (HSV-1) and HSV-2 in surgical specimens from patients with epilepsy by using polymerase chain reaction and Southern blot analysis.

Background:  Herpes simplex virus is a common neurotropic virus capable of latency within the central nervous system; it has a predilection for the temporal lobe. Central nervous system infection with HSV has been associated with seizure activity.

Design and Methods:  Surgical specimens were removed from 50 patients as part of a treatment protocol for monofocal epilepsy. Neuropathological classification was done, and adjacent sections were screened for HSV by using polymerase chain reaction. Tissues obtained post mortem from the temporal lobe cortex of persons with Alzheimer disease (n=17), Parkinson disease (n=14), or nonneurological disease (n=17) served as controls.

Results:  Twenty (40%) of the 50 epilepsy cases and 2 (4%) of the 48 control cases had at least one sample that tested positive for HSV (P<.001). Sixty-seven percent (8/12) of the epilepsy cases with heterotopia were positive for HSV.

Conclusions:  There was a statistically significant difference in the frequency of HSV-positive surgical specimens from monofocal seizure epicenters compared with nonepilepsy control specimens. These data suggest an association of the virus with seizure activity. All specimens positive for HSV (surgical specimens and control specimens) should be examined to determine the activity or latency state of the virus and cellular localization.