BK virus-associated infection in cerebrospinal fluid of neurological patients and mutation analysis of the complete VP1 gene in different patient groups.

While BK virus (BKV) is frequently associated with pathological conditions in bone marrow and renal transplant recipients, BKV infection in neurological individuals has been rarely reported. As a result of a BKV, JCV, and SV40 large T antigen-specific multiplex PCR on 2,062 cerebrospinal fluid (CSF) samples from neurological patients suspicious of JCV infection, we identified 20 subjects with at least 1 CSF specimen positive for BKV large T antigen DNA. Because VP1 protein has been suggested to influence the biological/pathological properties of BKV, we tried to sequence the entire VP1 gene in the BKV-positive neurological patients and succeeded in 14 of the 20 neurological patients. To compare the VP1 sequence of the BKV neurological strains with that of non-neurotropic strains in other clinical situations, full-length VP1 DNA was sequenced in 15 renal and 6 bone marrow transplant recipients positive to BKV-viremia, and in 8 pregnant women as non-pathological controls. An increased (respectively, decreased) tendency for mutations in the BC loop (respectively, EF loop) was observed, and no mutations were detected in the CD, GH, and HI loops. Subtype I was predominant (93%) and compared to archetypal BKV (WW), amino acid substitutions were detected in 4/14 neurological patients, 10/15 renal transplant recipients, 3/6 bone marrow transplant patients, and in all the pregnant women. Each patient group had distinctive VP1 mutations, but these unique substitutions were not present in all patients of this group. However, molecular modeling simulations of the VP1 mutants predicted changes in protein surface properties which might affect the VP1-receptor interaction.

BK polyomavirus with archetypal and rearranged non-coding control regions is present in cerebrospinal fluids from patients with neurological complications.

BK polyomavirus (BKPyV) has recently been postulated as an emerging opportunistic pathogen of the human central nervous system (CNS), but it is not known whether specific strains are associated with the neurotropic character of BKPyV. The presence of BKPyV large T-antigen DNA was examined in 2406 cerebrospinal fluid (CSF) samples from neurological patients with suspected JC polyomavirus infection. Twenty patients had a large T-antigen DNA-positive specimen. The non-coding control region (NCCR) of the BKPyV strains amplified from CSF from these 20 patients, strains circulating in renal and bone marrow transplant recipients and from healthy pregnant women was sequenced. The archetypal conformation was the most prevalent in all groups and 14 of the neurological patients harboured archetypal strains, while the remaining six patients possessed BKPyV with rearranged NCCR similar to previously reported variants from non-neurological patients. Transfection studies in Vero cells revealed that five of six early and four of six late rearranged promoters of these CSF isolates showed significantly higher activity than the corresponding archetypal promoter. From seven of the neurological patients with BKPyV DNA-positive CSF, paired serum samples were available. Five of them were negative for BKPyV DNA, while serum from the remaining two patients harboured BKPyV strains with archetypal NCCR that differed from those present in their CSF. Our results suggest that NCCR rearrangements are not a hallmark for BKPyV neurotropism and the dissemination of a rearranged NCCR from the blood may not be the origin of BKPyV CNS infection.

Mumps-associated meningitis and encephalitis in patients with no suspected mumps infection.

Mumps virus (MuV) was detected in the cerebrospinal fluid (CSF) of 6 of 158 patients with meningitis or encephalitis in absence of clinical mumps in the context of mumps epidemics. Our results suggest the need for the study of MuV RNA in the CSF of neurological patients in this context.

Development and validation with clinical samples of internally controlled multiplex real-time PCR for diagnosis of BKV and JCV infection in associated pathologies.

This article describes the development and validation with clinical samples of an internally controlled multiplex quantitative real-time PCR (QRT-PCR) for human polyomaviruses BK (BKV) and JC (JCV). Blood and urine samples from renal transplant recipients with suspected nephropathy, and cerebrospinal fluid (CSF) specimens from AIDS, natalizumab-treated and HIV-negative patients with suspected progressive multifocal leukoencephalopathy, previously checked for BKV and JCV by conventional PCR, were tested by QRT-PCR. All samples positive by conventional PCR were confirmed by QRT-PCR. Four cases of JCV-associated neurological infection, including all those detected in natalizumab-treated patients, and one case of BKV-related neurological infection were only identified by QRT-PCR. BKV was quantified in the CSF of neurological patients for the first time. Analyses of the Quality Control for Molecular Diagnostics 2010 panel were "highly satisfactory" for BKV and "satisfactory" for JCV. The QRT-PCR is specific and reproducible. It improves the sensitivity of conventional PCR for the diagnosis of BKV and JCV infection in various diseases.