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 f luid (CSF) is prognostic of survival and is a marker of the course of progr essive multifocal leukoencephalopathy (PML). CSF samples from 15 acquired i mmunodeficiency syndrome (AIDS) patients with biopsy-proven PML were analyz ed by semiquantitative polymerase chain reaction (PCR). A low JCV burden wa s predictive of longer survival compared with a high JCV burden (median sur vival from entry, 24 [2-63] vs 7.6 [4-17] weeks). Further analyses indicate d a possible threshold of 50 to 100 copies/mu l separating high- and modera te-risk cases. Patients with a JCV load below this level survived longer th an those with a JCV load above it.