[Critical study of the serological diagnosis of herpetic encephalitis. Apropos of 4 cases].

Virologic study was performed in four cases of Herpes simplex virus encephalitis. Herpes simplex virus type 1 was recovered from surgical brain biopsy specimens taken in three cases. Anti-HSV antibodies were assayed in simultaneous blood and cerebrospinal fluid samples by ELISA. CSF and serum specific antibody ratios were compared to those of antibodies directed against other viral antigens whenever possible. A significant and early increase in this CSF/serum ratio was demonstrated in two patients. The diagnostic value of this serological method is discussed, as an alternative to viral isolation from brain biopsy specimens.