Progressive multifocal leukoencephalopathy-remission with cytarabine.

A 51-year-old woman who was in complete remission from non-Hodgkin's lymphoma, developed a rapidly progressive dementia. Progressive multifocal leukoencephalopathy (PML) was diagnosed on the basis of a rising antibody titre to JC polyomavirus in cerebro-spinal fluid and serum and the presence of diffuse white matter changes on magnetic resonance imaging. She was treated initially with intravenous cytarabine and showed minimal improvement. Rapid improvement occurred when intrathecal cytarabine was added and the patient is in complete remission from both lymphoma and PML 20 months later.

Analysis of retinoblastoma for human adenovirus and human JC virus genome integration.

Human adenovirus groups A and B have an oncogenic potential in newborn rodents. Especially, adenovirus type 12 is known to induce retinoblastoma-like tumor in baboons and transform human embryo retinoblast cells in vitro. Human JC virus is also known to produce a variety of tumors in newborn rodents, including retinoblastoma-like tumor. In this experiment, cell DNAs of human retinoblastomas were assayed for each of the transforming gene sequences of adenovirus groups A, B, C, D and E and for JC virus gene sequences, by using Southern blot hybridization. None of these viral gene sequences were detected at the level of 0.1-0.5 copy per diploid cell DNA in all of 11 retinoblastomas, including 6 retinoblastomas previously examined for adenovirus 12-transforming gene sequences. This led to a conclusion that most, if not all, adenoviruses and JC virus play no essential role in the etiology of human retinoblastoma, although there were experimental models of retinoblastoma induced by these viruses.

Progressive multifocal leucoencephalopathy: analysis of JC virus DNA from brain and kidney tissue.

JC virus-specific DNA from both brain and kidney of the PML case G.S. was analysed by restriction mapping and Southern blot analysis. The genome of JCV DNA from brain (JCV GS-B) was full length, whereas JCV DNA GS from kidney (JCV GS-K) was 120 bp smaller. Restriction maps, constructed from JCV GS-B using various enzymes showed that most cleavage sites were consistent with standard map sites. Comparison of virus DNA from brain and kidney revealed that JCV GS-specific cleavage sites were identical, and that the DNAs were therefore of the same subtype. The deletion in kidney DNA was situated in the area of the origin of replication which is known to be hypervariable in the JCV genome. Restriction maps revealed that the DNA from each organ was homogeneous in length but a proportion of the DNA molecules were heterogeneous in restriction sites. It is concluded from these data that initial infection with one JCV subtype was followed by the development of heterogeneous DNA molecules.

Characterization of tissue culture-induced heterogeneity in DNAs of independent isolates of JC virus.

After several serial passages at low multiplicities of infection in primary human foetal glial cells at 37 degrees C, the DNA of prototype (MAD-1) JC virus and that of MAD-2 and MAD-3 are typically heterogeneous in size, but DNAs of MAD-4 and MAD-6 are relatively homogeneous. A similar dichotomy was observed in the DNAs of six isolates propagated more recently in glial cultures at 39 degrees C under similar conditions of brief passage in vitro at low multiplicities of infection: the DNAs of two (MAD-9 and -10) were heterogeneous, but the DNAs of four others (MAD-8, -11, -12 and -14) were homogeneous. Therefore, the propensity of the viral genome to sustain deletions was an intrinsic property of each isolate. However, actual induction and maintenance of the presumably defective DNAs was influenced by the relative proportions of permissive spongioblasts and semi-permissive astrocytes in the glial cultures and by the multiplicity of infection. Deletions in MAD-1 DNA were confined to the presumptive early region and spanned the BamHI cleavage site (map position 0.505). The heterogeneity was more complex in the DNAs of MAD-2 and MAD-3, but again most of the deletions, which ranged up to 12% of full-length DNA, spanned the BamHI site. We propose that the differential susceptibility to deletion among isolates is a consequence of natural genetic variation in JC virus.

JC virus T protein expression in owl monkey tumor cell lines.

Four owl monkey tumor cell lines were tested for the presence of JCV early gene products. Owl 26 was the only cell line in which large T protein could be immunoprecipitated using cross-reactive anti-SV40 hamster tumor sera. Small t protein could not be detected in any of the four cell lines. The monoclonal antibody Cl 122, directed against the host-cell 53K protein, could bind the SV40-T-53K host protein complex in human embryonic kidney cells transformed by SV40. However, the Cl 122 antibody only reacted with a 53K protein in Owl 26 not complexed with the JCV T protein.

Progressive multifocal leucoencephalopathy: detection of papovavirus JC in kidney tissue.

Cellular DNA of the kidney from a patient with PML was analyzed by reassociation kinetics for the presence of JC virus DNA. Various amounts of viral DNA sequences were detected in different areas of the kidney. The highest concentration (175 genome equivalents/cell) was found in the renal medulla and there were almost none in the renal cortex. Differentiation from the closely related BK virus was carried out by reassociation kinetics and restriction enzyme cleavage with subsequent Southern blot analysis. The enzyme Hind II, which does not cleave within the BK virus genome, generated four restriction enzyme fragments in the cellular DNA from the kidney, thus documenting the presence of JC virus DNA. By examination of the renal DNA with the "no-cut" restriction enzyme XHO I and the "one-cut" enzymes Eco RI and BAM HI it was possible to show that free and not integrated viral DNA was present in these cells. Nonhomogeneous defective DNA bands were not detectable. By in situ hybridization the epithelial cells lining the collecting tubules were found as predominant site of the viral infection in the kidney.