Fluorescence and neutralizing antibodies to herpes simplex virus in the cerebrospinal fluid of patients with central nervous system diseases.

Herpes simplex virus antibodies were studied in 73 patients with various diseases of the central nervous system. In 29 patients, there were rising titers of fluorescence and neutralizing antibodies to herpes simplex virus in the cerebrospinal fluid (CSF). The CSF antibodies were predominantly IgG. In one patient, IgM was found during the fourth, but not during the eighth week of illness. The CSF antibody titers did not correlate with the serum antibody titers or with the severity of the neurologic defect. No fluorescence antibodies were found in the CSF of 52 of 53 control patients. The presence of CSF fluorescence antibodies may be of considerable value in the diagnosis of herpes simplex encephalitis. However, the absence of these antibodies in the early stage of the disease does not exclude the possibility of infection with herpes simplex virus.