Presence of herpes simplex DNA in surgical tissue from human epileptic seizure foci detected by polymerase chain reaction: preliminary study
V. J. Sanders, S. L. Felisan, A. E. Waddell, A. J. Conrad, P. Schmid, B. E. Swartz, M. Kaufman, G. O. Walsh, A. A. De Salles and W. W. Tourtellotte
Department of Neurology, the University of California, Los Angeles School of Medicine, USA.
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.
