Herpes simplex encephalitis: A serological follow-up study. Synthesis of herpes simplex virus immunoglobulin M, A, and G antibodies and development of oligoclonal immunoglobulin G in the central nervous system.

A solid-phase radioimmunoassay method was used for the detection of herpes simplex virus (HSV) immunoglobulin M (IgM), IgA, and IgG antibodies within the central nervous system in 11 patients with acute HSV encephalitis. Serial cerebrospinal fluid (CSF) and serum specimens were sampled during the observation periods, extending up to 43 months after onset. The clinical diagnosis of HSV encephalitis was confirmed demonstrating virus or virus antigen in the central nervous system in four patients and with significant HSV antibodies in CSF in all the patients. In acute stage CSF HSV antibodies of a significant level were demonstrated in one of four samples taken on days 3--4 after onset, and in samples taken on days 6--8 in five of nine patients. CSF HSV antibodies of a significant and high level were detected in all samples taken from day 10 after onset. Intrathecal production of HSV IgM and IgA antibodies lasted from 7 weeks to 43 months during the observation periods. All patients had persistent intrathecal production of HSV IgG antibodies as well as of oligoclonal IgG during the total observation periods up to 43 months.