[Progressive multifocal leukoencephalopathy]

Progressive multifocal leukoencephalopathy (PML) is the only polyomavirus infection in human caused by JC virus. Clinically PML is diagnosed by neurological signs, supported by MRI and PET, but its pathologic diagnosis at brain biopsy remains to be a confirmative method, although the PCR method, using csf, gives a predictive value. Virological study of the regulatory region of viral genome has suggested that PML-inducing viral type may be derived from the urine-excreted virus (archetype) by mechanisms involving nucleotide deletion and duplication. Viral neurotropism has been shown to be closely related to transcriptional function of the viral promoter-enhancer which cellular proteins bind to and is activate by. Of these, NF-1 binding proteins, glial factor-1, Tst-1 (SCIP, Oct-6) and others should be tested for their specificity to human glial cell.