Detection of herpes simplex virus type 1-IgM immune complexes in the brain of a patient with prolonged herpes encephalitis.

A 56-year-old man with herpes encephalitis died 5.5 months after disease onset. Herpes simplex virus was isolated from minced temporal lobe after one month of cocultivation with green monkey kidney cells. The virus was identified as type 1 by neutralization and the fingerprinting pattern on restriction enzyme digestion. By immunofluorescence, IgM deposition was seen in the cerebral vascular walls. After dissociation of IgM with 3.0 M NaSCN, viral antigen was noted at the same loci as the IgM deposition. Histopathology showed marked perivascular cuffings, approximately 80% of which consisted of T cells and widely distributed necrotic foci. When the patient's serum and spinal fluid were analyzed by the immunoblotting method, the spinal fluid contained antibodies that were reactive with two very-high-molecular-weight viral polypeptides.