SPECIFIC DIAGNOSIS OF PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY BY POLYMERASE CHAIN-REACTION

Using polymerase chain reaction (PCR), 34 cerebrospinal fluid (CSF) sa mples from 28 patients with progressive multifocal leukoencephalopathy (PML) were analyzed. As controls, 116 samples were evaluated from 82 human immunodeficiency virus type 1 (HIV-1)-infected patients and 1 HI V-1-negative patient. Of the HIV-1-positive patients, 23 had cerebral toxoplasmosis, 10 had HIV leukoencephalopathy, and 49 had other neurol ogic complications. Detection of JC virus (JCV) DNA in CSF was increas ed 10-fold by the addition of carrier DNA before phenol-chloroform-iso amyl alcohol extraction. The primer pair JC 26/29, from the VP1/large T region, had a limit of detection of 10(5) JCV DNA molecules/100 mu L . The primer pair JC 36/39, located in the large T gene region, had a 100-fold lower limit of detection. With JC 26/29, the sensitivity was 43% (12/28) and specificity was 100%. Using JC 36/39, sensitivity incr eased to 82% (23/28), and false-positive results were not observed. Di agnosis of PML is greatly aided by PCR analysis of CSF.