[Detection of antigen and antibody in herpes simplex encephalitis]

Laboratory confirmation of herpes simplex (HSV) infection in patients suspected of HSV encephalitis (HSV-E) at the earliest stage of the disease, may contribute greatly to the differential diagnosis and to the initiation of effective antiviral treatment. Our diagnosis of HSV infection was based on: a) detection of viral antigen in CSF cells in the first week of disease by immunofluorescence assay employing monoclonal antibodies against HSV-1 or HSV-2; b) detection of local IgM- and IgG-specific antibodies to HSV in the CSF and in the serum; c) ratio of titers of HSV antibodies in CSF and in serum less than 1:20; d) 4-fold rise in antibody titer to HSV in CSF and/or serum. The incidence of HSV-E was examined through 1987 in 270 patients suspected of viral infection of the central nervous system. In 187 (69.5%) material for laboratory diagnosis was inadequate and in 75 (27.8%) no evidence for infection by HSV was found. HSV infection was confirmed in 8 (2.9%), comprising 9.6% of those with adequate material for laboratory diagnosis. In no case was HSV isolated from the CSF. The importance of adequate material for viral diagnosis by the laboratory is emphasized.