Etiology of Progressive Multifocal Leukoencephalopathy

Abstract
Papovaviruses were identified in brains of 13 patients with progressive multifocal leukoencephalopathy, asubacute human demyelinating disease. Fluorescent-antibody staining and electron microscopical agglutination technics demonstrated the JC type of papovavirus in 11 patients. Simian-virus 40 and the virus of progressive multifocal leukoencephalopathy were isolated from the first two patients studied, but all subsequent isolates were of the JC-virus type, and the BK type was not implicated in the disease. The use of monospecific rabbit serums to identify viral antigens in the brain tissue of patients and to serotype by electron microscopy virions extracted directly from brain demonstrates that rapid diagnostic methods can be employed in this disease. (N Engl J Med 289:1278–1282, 1973)