Isolation of herpes simplex virus type 1 during first attack of multiple sclerosis.

Herpes simplex virus type 1 was isolated from the cerebrospinal fluid of a patient during the first attack of multiple sclerosis. This is the first virus to be isolated from the central nervous system of a living patient with MS. The virus was identified as herpes simplex virus type 1 by restriction endonuclease analysis and by an enzyme immunoassay using monoclonal antibodies. Antibodies against type 1 but not type 2 were detected in consecutive samples of serum and cerebrospinal fluid. The patient has since entered a progressive phase of multiple sclerosis. The isolated type 1 strain might be of pathogenetic relevance to the development of multiple sclerosis in this patient.