Relation of JC virus DNA in the cerebrospinal fluid to survival in acquired immunodeficiency syndrome patients with biopsy-proven progressive multifocal leukoencephalopathy.

The detection and semiquantitation of JC virus (JCV) DNA in cerebrospinal fluid (CSF) is prognostic of survival and is a marker of the course of progressive multifocal leukoencephalopathy (PML). CSF samples from 15 acquired immunodeficiency syndrome (AIDS) patients with biopsy-proven PML were analyzed by semiquantitative polymerase chain reaction (PCR). A low JCV burden was predictive of longer survival compared with a high JCV burden (median survival from entry, 24 [2-63] vs 7.6 [4-17] weeks). Further analyses indicated a possible threshold of 50 to 100 copies/microl separating high- and moderate-risk cases. Patients with a JCV load below this level survived longer than those with a JCV load above it.