They then return to normal for
weeks, months or years until the next episode. Usually, after
several attacks, the condition seems to ‘‘burn out’’ within a
few years. Examination of the CSF during an episode shows a
pleocytosis, sometimes several thousand cells per microlitre,
with lymphocytes, neutrophils and so-called ‘‘Mollaret
cells’’—large, friable cells with faintly staining vacuolated
cytoplasm. These cells originally were thought to be
endothelial but are now considered to be activated macrophages
and are not pathognomonic of the disorder. Whether
the term ‘‘Mollaret’s meningitis’’ will survive the discovery of
an association with HSV (usually HSV-2) in many of these
patients10 is both a semantic and a practical issue.