Detection of JC virus DNA in the cerebrospinal fluid of patients with progressive multifocal leukoencephalopathy.

JC virus (JCV) DNA was detected by polymerase chain reaction (PCR) amplification in the cerebrospinal fluid (CSF) of 10 of 13 patients with a diagnosis of progressive multifocal leukoencephalopathy (PML) previously confirmed by histological and virological techniques. It was not found in 42 CSF samples from 41 patients who did not have PML. Four sets of primers were used to amplify polyomavirus DNA. One was from the region of the genome coding the T antigen, a conserved region common to JC and BK viruses. A second set nested to these was used as a confirmatory test in a secondary PCR. The remaining two were from the region of the genome coding VP1, one specific for JCV and the other for BKV. CSF did not inhibit the PCR and preliminary DNA extraction was not considered necessary.