Subacute sclerosing panencephalitis after passive immunization and natural measles infection: role of antibody in persistence of measles virus.

Subacute sclerosing panencephalitis (SSPE) developed in a patient in whom natural measles infection was anteceded by immunization with measles immune serum globulin (ISG). This observation prompted experimental studies of the role of antibody in viral persistence. When Balb/c mice were infected with the hamster neurotropic measles virus, acute encephalopathy was fatal in 80% of the animals. When measles antibody was administered 3 days after virus inoculation, the acute disease was abolished and subacute encephalitis had a 30% mortality. The subacute disease was characterized by the presence of neuronal viral antigen, meningitis, and encephalitis. Induction of viral persistence was therefore a consequence of antibody transfer during viral infection. Caution is advised in human prophylaxis with immune globulin.