Herpes simplex encephalitis: further evidence for persistent infection in the CNS.

Herpes simplex virus (HSV) antibody titers and IgG, IgM and IgA concentrations in the cerebrospinal fluid were serially measured in a patient with HSV encephalitis during a follow-up period of 32 months. HSV antibody titers, all classes of immunoglobulins and Ig% showed significant elevation during the course of illness, though IgM% and IgA% gradually declined after the acute phase. Autopsied brain tissue failed to yield a virus isolate, but conspicuous perivascular lymphocyte infiltrate, which is compatible with HSV encephalitis, was seen. These observations suggest the occurrence of HSV persistence and persistent antigen stimulation in the central nervous system, analogous to the well-recognized latent condition within the trigeminal ganglion.