Monitoring and tentative diagnosis of herpetic encephalitis by protein analysis of cerebrospinal fluid. Particular relevance of the assays of ferritin and S-100.

The cerebrospinal fluid (CSF) of 9 patients with herpetic encephalitis was analyzed by particle counting immunoassay of ferritin, S-100, immunoglobulins, anti-herpes antibodies and immune complexes and by electrophoresis for the detection of oligoclonal bands. The main conclusions are: first, the simultaneous increase of both ferritin and S-100 in the presence of symptoms of encephalitis suggests strongly the infection is herpetic; second, high and increasing levels of S-100, probably related to the extent of the necrotic process, indicate a poor prognosis. In addition, 8-14 days after onset, locally produced anti-herpes antibodies were detectable, the IgG index increased and oligoclonal bands became visible.