Genetic analysis of JC virus and BK virus from a patient with progressive multifocal leukoencephalopathy with hyper IgM syndrome.

A case of acute progressive multifocal leukoencephalopathy (PML) with hyper IgM syndrome 1 is reported. Viral DNA and VP1 protein of JC virus (JCV) and BK virus (BKV) were detected by immunohistochemistry, in situ hybridization, semi-nested polymerase chain (PCR) and PCR-restriction enzyme analysis. JCV DNA and VP1 protein were found in the nuclei of oligodendrocytes. The non-coding control region (NCCR) and VP1 region of the JCV genome were sequenced; this revealed a novel rearrangement pattern of the NCCR in the brain tissue. The VP1 regions of brain and urine JCV were identical and of genotype type 2A. The BKV in the urine sample was genotype I. No BKV genome was found in the brain. The novel genomic rearrangement of the JCV NCCR in the brain tissue may have altered JCV pathogenesis to induce PML; the impaired immunity from hyper IgM syndrome 1 may have enabled the rearrangement. The JCV NCCR rearrangement in the brain may have originated from the archetypal form in the urine through deletion and duplication.