1/9. Molecular characterization and sequence analysis of polyomavirus BKV-strain in a renal-allograft recipient.The significance of polyomavirus (PV) infection was investigated in a 53-year-old patient who underwent renal transplantation and was treated with triple immunosuppressive therapy (tacrolimus, prednisone, and azathioprine). A renal biopsy taken because of the suspicion of acute rejection showed focal inflammatory interstitial infiltration, tubulitis, and tubular cell nuclear changes consistent with the hypothesis of viral infection. Both the tubular and decoy cells identified by means of urinalysis positively stained for anti-SV40 antibody. polymerase chain reaction performed on the DNA extracted from renal tissue and isolated from urine showed the presence of an antigenic variant (AS) of the BKV archetype after sequence analysis of the transcription control region (TCR). On the basis of the diagnosis of BKV infection, immunosuppressive therapy was reduced. The patient's renal function improved and was still stable 8 months later when urinalysis showed only a few decoy cells, which were found to be infected by JC but not bk virus. These data suggest that only the BKV, probably favoured by immunosuppressive therapy (tacrolimus), causes renal damage. It is worth underlining that even small and sporadic viral genome mutations may lead to pathologic effects.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
2/9. BK polyomavirus interstitial nephritis in a renal transplant patient with no previous acute rejection episodes.A renal transplant patient treated with tacrolimus and mycophenolate-mofetil (MMF) developed progressive graft function deterioration 10 months after transplantation. biopsy of the graft showed severe, focally accentuated interstitial inflammation with focal tubulitis and tubular necrosis, and medium-severe interstitial fibrosis with focal tubular atrophy. Glomerular and vascular structures were preserved. On careful examination, in some sections, tubular epithelial cells showed a definite increase with deformation of the nuclear shape, chromatin irregularities with peripheral dislocation and inclusion bodies. These cytopathic changes suggested polyoma virus infection ("decoy cells"). Subsequent screening of the urinary sediment confirmed the presence of many "decoy cells". Immunohistochemical analysis of the biopsy showed many tubular cells were strongly positive for the SV 40 antigen, specific for BK polyoma virus. A diagnosis of interstitial nephritis due to BK polyoma virus was made, though the coexistence of cellular rejection could not be excluded. At variance with previous reports, our patient had not had repeated episodes of rejection before biopsy or heavy immunosuppressive treatment, such as ALG, OKT3, after transplantation. This case shows that even in the absence of vigorous anti-rejection therapy an immunosuppressive regimen based on tacrolimus and MMF may involve the risk of BK polyoma virus- associated interstitial nephritis.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
3/9. Bladder carcinoma in a transplant recipient: evidence to implicate the BK human polyomavirus as a causal transforming agent.The BK polyomavirus (BKV) infects most of the human population, but clinically relevant infections are mostly limited to individuals who are immunosuppressed. In transplant recipients, BKV has been associated with ureteral stenosis, interstitial nephritis, and hemorrhagic cystitis. The role of BKV in the development of human tumors is intriguing but uncertain. BKV has been identified in various tumor types including urothelial carcinoma, but the ubiquitous presence of BKV as a latent infection has confounded efforts to validate any causal role in cancer development. We report the case of a simultaneous pancreas and kidney transplant recipient who developed BKV interstitial nephritis and carcinoma of the bladder with widespread metastases. High level expression of BKV large T antigen in the primary and metastatic carcinoma, but not in the nonneoplastic urothelium, implicates BKV as an etiologic agent in the development of this tumor.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
4/9. bk virus nephropathy in a patient with ABO-incompatible renal transplantation.A 43-year-old woman with end-stage renal disease originating from IgA nephropathy entered chronic haemodialysis therapy. She then received an ABO-incompatible living related renal transplantation. Initial immunosuppression consisted of azathioprine, methylprednisolone and tacrolimus. At 155 days after transplantation, the azathioprine was changed to mycophenolate mofetil for continuous graft dysfunction. Furthermore, a total of three courses of anti-rejection therapy was given. At 665 days after transplantation, diagnosis of BK-virus nephropathy was made by immunohistochemical analysis and viral DNA assay. Therefore the immunosuppression therapy was reduced for graft dysfunction. All five renal biopsy specimens were examined retrospectively in order to determine when the bk virus nephropathy had developed. The expressions of SV40 large T antigens were detected from the third (117 days) to the fifth (665 days) biopsies, with increasing numbers of SV40 large T antigen positive cells. In addition, many cells contained inclusion bodies which were already present in the urinary sediment for 3 months post-transplantation. Although it is difficult to make a diagnosis of early stage of BKVN, we have to consider with caution if urinary cells with inclusion body are seen. awareness of BKVN at the earliest opportunity is important in order to avoid over-immunosuppression.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |
5/9. bk virus subtype 1 infection associated with tubulointerstitial nephritis in a renal allograft recipient.The BK polyomavirus (BKV) infects most of the human population, but clinically relevant infections are usually limited to individuals who are in an immunosuppressed state. The significance of BKV infection was investigated in a 50-year-old man who underwent cadaveric kidney transplantation and was treated with tacrolimus, mycophenolate mofetil and prednisolone. By staining renal biopsy specimens with a monoclonal antibody against BK large T antigen, we were able to observe the relationship between the appearance of the BKV antigen and the extent of immunosuppression in this patient. We also determined that BKV belonged to genotype I by analysis of viral DNA from the patient's urine.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |
6/9. LT, VP1 and TCR-BKV sequence analysis in a patient with post-transplant BKV nephropathy associated with EBV-related PTLD.A 10-year-old boy kidney transplant recipient (KTR) developed an abdominal post-transplant lymphoproliferative syndrome (PTLD) followed by bk virus nephropathy (BKVN). bk virus (BKV) and Epstein-Barr virus (EBV) were studied in renal and PTLD tissue by polymerase chain reaction (PCR) assay. Afterwards, the patient was monitored in relation to BKV in urine and serum; transcription control region (TCR)-BK polymorphism sequence analysis was also performed. In the PCR assay, both early large T antigen (LT) and late (VP1) transcriptional BKV coding regions were found in renal tissue, whereas EBV and only LT-BK were detected in PTLD abdominal tissue. On the other hand, TCR sequence analysis revealed the AS genomic BK variant.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
7/9. glioblastoma multiforme with small cell neuronal-like component: association with human neurotropic jc virus.The human polyomavirus JCV, the etiological agent of progressive multifocal leukoencephalopathy, has been associated with primitive neuroectodermal tumors and various glial-derived tumors, including glioblastoma multiforme (GBM). Here we describe the unique clinical case of a 54-year-old man who presented with headaches, hemiparesis and drowsiness. T1 and T2 magnetic resonance images revealed a large solid tumor with a cystic component located in the right temporal lobe, with extension into the parietal lobe. Histologically, the tumor was composed of two areas, a main area of large neoplastic cells with pleomorphic atypical nuclei and abundant cytoplasm, which by immunohistochemistry was reactive for glial fibrillary acidic protein, mixed with several foci of poorly differentiated tumoral cells with elongated nuclei and scant cytoplasm, negative for GFAP, but robustly immunoreactive for synaptophysin and phosphoneurofilaments. Results from PCR in laser capture microdissected cells from both areas of the tumor revealed the presence of DNA sequences corresponding to the early, late and control regions (CR) of the JCV genome and expression of JCV proteins T-antigen and Agnoprotein in both phenotypes. No evidence for capsid protein was observed, excluding productive viral infection. Sequencing demonstrated the presence of the JCV Mad-1 strain with distinct point mutations in the CR of isolates from both, GBM and small cell architectural areas. The presence of JCV DNA sequences and expression of viral proteins further reinforces the role of the widely spread human neurotropic virus in early transformation and in the development of brain tumors.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
8/9. Renal transplant patient with polyoma virus bladder infection and subsequent polyoma virus nephropathy.Polyoma virus nephropathy (PVN) is a significant cause of renal allograft dysfunction in transplant patients. A 58-year-old male received a cadaveric renal transplant and 12 weeks later presented with fever, diarrhea, and dysuria. He was diagnosed with a polyoma virus infection of the bladder by a transurethral bladder biopsy. One year post-transplant, he presented with renal allograft dysfunction and was diagnosed by biopsy with PVN of the non-native kidney. The diagnosis of a polyoma virus infection was confirmed by immunoreactivity to the polyoma T-antigen. We suggest that polyoma virus infection of the bladder be included in the differential diagnosis of urinary dysfunction in post-transplant patients, as such infections might be an under-recognized comorbidity in individuals with PVN.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
9/9. Tubulointerstitial nephritis due to a mutant polyomavirus bk virus strain, BKV(Cin), causing end-stage renal disease.A renal biopsy from a 36-year-old man with AIDS showed a severe tubulointerstitial nephritis with intranuclear inclusions in epithelial cells. Electron microscopy revealed the characteristic findings of a polyomavirus (PyV) infection, and immunofluorescence indicated the presence of bk virus (BKV) antigen. Inoculation of rhesus monkey kidney cell cultures both with urine and with buffy coat blood cells resulted in a cytopathic response which was subsequently confirmed to be due to BKV. Further characterization of the viral DNA from the kidney by PCR amplification and Southern blot analysis with PyV and strain-specific primers and probes indicated that the virus was closely related to the BK(Dun) strain but different in its apparent sequence arrangement. Subsequent cycle sequencing showed a dinucleotide mutation of TG-->AA which substitutes hydrophilic Gln for hydrophobic Leu in a sequence homologous to an origin DNA-binding domain of simian virus 40 T antigen. It is suggested that the mutation and a coding region rearrangement of this strain of BKV designated BKV(Cin) has the potential to alter viral dna replication and enhance pathogenicity.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |