ABSTRACT
Active replication of the Polyomavirus hominis 2 (JCV) in glial cells leads to the fatal, demyelinating disease of the central nervous system, called progressive multifocal leukoencephalopathy (PML). Although more than 80% of the population is infected a significant impairment of the immune system is needed for reactivation of the latent virus. Such reactivation can be verified by a Polymerase Chain Reaction (PCR) test for detection of JCV DNA in brain tissue or cerebrospinal fluid (CSF). Here we report and discuss two cases of Bulgarian HIV-infected patients where identification of JCV supported and confirmed the diagnosis of HIV-associated PML.