RESUMEN
OBJECTIVE: To evaluate the presence of JC virus DNA in CSF samples from Brazilian AIDS patients with focal lesions of CNS white matter without mass effect compatible with progressive multifocal leukoencephalopathy (PML). METHODS: CSF samples from AIDS patients with neurological symptoms and a CT scan showing focal lesions of CNS white matter without mass effect suggestive of PML, and from AIDS and non-AIDS patients with non-PML neurological diseases were tested for JC virus DNA by PCR. The primers used to amplify the T antigen region of the JC virus resulted in a 173-bp fragment. The presence of the JC virus was confirmed by digestion of the PCR product using BamH1. RESULTS: The PCR for JCV DNA was negative in 119/120 non-PML CSF samples (specificity =99.2%). Of 56 CSF samples from AIDS patients with focal lesions of CNS white matter without mass effect, JCV DNA was positive in 48.2% (27/56). In 23/29 (79.3%) JCV DNA-negative cases, other causes for the encephalitic lesions were found. No JCV DNA-positive cases showed other diagnoses. CONCLUSIONS: The prevalence of JCV DNA by PCR in CSF samples from Brazilian AIDS patients with focal brain lesions, without mass effect was 48.2%. In these patients, a negative JCV PCR is highly suggestive of other neurological conditions.