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Journal of Clinical Microbiology Sep 2022Quantitative testing of BK virus (BKPyV) nucleic acid has become the standard of care in transplant patients. While the relationship between interassay harmonization and...
Quantitative testing of BK virus (BKPyV) nucleic acid has become the standard of care in transplant patients. While the relationship between interassay harmonization and commutability has been well characterized for other transplant-related viruses, it has been less well studied for BKPyV, particularly regarding differences in commutability between matrices. Here, interassay agreement was evaluated among six real-time nucleic acid amplification tests (NAATs) and one digital PCR (dPCR) BKPyV assay. Differences in the commutability of three quantitative standards was examined across all assays using a variety of statistical approaches. Panels, including 40 samples each of plasma and urine samples previously positive for BKPyV, together with one previously negative plasma sample and four previously negative urine samples, were tested using all assays, with each real-time NAAT utilizing its usual quantitative calibrators. Serial dilutions of WHO, National Institute for Standards and Technology (NIST), and commercially produced (Exact/Bio-Rad) reference materials were also run by each assay as unknowns. The agreement of the clinical sample values was assessed as a group and in a pairwise manner. The commutability was estimated using both relativistic and quantitative means. The quantitative agreement across assays in the urine samples was within a single log unit across all assays, while the results from the plasma samples varied by 2 to 3 log IU/mL. The commutability showed a similar disparity between the matrices. Recalibration using international standards diminished the resulting discrepancies in some but not all cases. Differences in the sample matrix can affect the commutability and interassay agreement of quantitative BKPyV assays. Differences in commutability between matrices may largely be due to factors other than those such as amplicon size, previously described as important in the case of cytomegalovirus. Continued efforts to standardize viral load measurements must address multiple sources of variability and account for differences in assay systems, quantitative standards, and sample matrices.
Topics: BK Virus; Cytomegalovirus; Humans; Nucleic Acids; Reference Standards; Viral Load
PubMed: 35997500
DOI: 10.1128/jcm.00555-22 -
Clinical Transplantation Nov 2022BK polyomavirus-associated nephropathy (BKPyVAN) carries a risk of irreversible allograft injury. While detection of BK viremia and biopsy assessment are the current...
BACKGROUND
BK polyomavirus-associated nephropathy (BKPyVAN) carries a risk of irreversible allograft injury. While detection of BK viremia and biopsy assessment are the current diagnostic gold standard, the diagnostic value of biomarkers reflecting tissue injury (donor-derived cell-free DNA [dd-cfDNA]) or immune activation (C-X-C motif chemokine ligand [CXCL]9 and CXCL10) remains poorly defined.
METHODS
For this retrospective study, 19 cases of BKPyVAN were selected from the Vienna transplant cohort (biopsies performed between 2012 and 2019). Eight patients with T cell-mediated rejection (TCMR), 17 with antibody-mediated rejection (ABMR) and 10 patients without polyomavirus nephropathy or rejection served as controls. Fractions of dd-cfDNA were quantified using next-generation sequencing and CXCL9 and CXCL10 were detected using multiplex immunoassays.
RESULTS
BKPyVAN was associated with a slight increase in dd-cfDNA (median; interquartile range: .38% [.27%-1.2%] vs. .21% [.12%-.34%] in non-rejecting control patients; p = .005). Levels were far lower than in ABMR (1.2% [.82%-2.5%]; p = .004]), but not different from TCMR (.54% [.26%-3.56%]; p = .52). Within the BKPyVAN cohort, we found no relationship between dd-cfDNA levels and the extent of tubulo-interstitial infiltrates, BKPyVAN class and BK viremia/viruria, respectively. In some contrast to dd-cfDNA, concentrations of urinary CXCL9 and CXCL10 exceeded those detected in ABMR, but similar increases were also found in TCMR.
CONCLUSION
BKPyVAN can induce moderate increases in dd-cfDNA and concomitant high urinary excretion of chemokines, but this pattern may be indistinguishable from that of TCMR. Our results argue against a significant value of these biomarkers to reliably distinguish BKPyVAN from rejection.
Topics: Humans; BK Virus; Retrospective Studies; Graft Rejection; Cell-Free Nucleic Acids; Kidney Transplantation; Polyomavirus Infections; Kidney Diseases; Viremia; Antibodies; Biomarkers
PubMed: 35894263
DOI: 10.1111/ctr.14785 -
Viruses May 2023Reactivation of JC and BK polyomaviruses during immunosuppression can lead to adverse clinical outcomes. In renal transplant recipients, BKV-associated nephropathy can...
BACKGROUND
Reactivation of JC and BK polyomaviruses during immunosuppression can lead to adverse clinical outcomes. In renal transplant recipients, BKV-associated nephropathy can result in graft loss, while in patients with autoimmune disorders, prolonged immunomodulatory drug use can cause rare onset of progressive multifocal leukoencephalopathy due to JCV reactivation. In such patients, accurate BK and JC viral load determinations by molecular technologies are important for diagnosis and clinical management; however, comparability across centres requires effective standardisation of diagnostic molecular detection systems. In October 2015, the WHO Expert Committee for Biological Standardisation (ECBS) established the 1st WHO International Standards (ISs) for use as primary-order calibrants for BKV and JCV nucleic acid detection. Two multi-centre collaborative studies confirmed their utility in harmonising agreement across the wide range of BKV and JCV assays, respectively. Previous Illumina-based deep sequence analysis of these standards, however, identified deletions in different regions, including the large T-antigen coding region. Hence, further detailed characterization was warranted.
METHODS
Comprehensive sequence characterisation of each preparation using short- and long-read next-generation sequencing technologies was performed with additional corroborative independent digital PCR (dPCR) determinations. Potential error rates associated with long-read sequencing were minimised by applying rolling circle amplification (RCA) protocols for viral DNA (circular dsDNA), generating a full validation of sequence identity and composition and delineating the integrity of full-length BK and JC genomes.
RESULTS
The analysed genomes displayed subpopulations frequently characterised by complex gene re-arrangements, duplications and deletions.
CONCLUSIONS
Despite the recognition of such polymorphisms using high-resolution sequencing methodologies, the ability of these reference materials to act to enhance assay harmonisation did not appear significantly impacted, based on data generated by the 2015 WHO collaborative studies, but highlights cautionary aspects of IS generation and commutability for clinical molecular diagnostic application.
Topics: Humans; JC Virus; BK Virus; Polyomavirus Infections; Leukoencephalopathy, Progressive Multifocal; DNA, Viral; World Health Organization; Tumor Virus Infections
PubMed: 37376589
DOI: 10.3390/v15061289 -
Pre-Transplantation Assessment of BK Virus Serostatus: Significance, Current Methods, and Obstacles.Viruses Oct 2019The immunosuppression required for graft tolerance in kidney transplant patients can trigger latent BK polyomavirus (BKPyV) reactivation, and the infection can progress... (Review)
Review
The immunosuppression required for graft tolerance in kidney transplant patients can trigger latent BK polyomavirus (BKPyV) reactivation, and the infection can progress to nephropathy and graft rejection. It has been suggested that pre-transplantation BKPyV serostatus in donors and recipients is a predictive marker for post-transplantation BKPyV replication. The fact that research laboratories have used many different assay techniques to determine BKPyV serostatus complicates these data analysis. Even studies based on the same technique differed in their standard controls choice, the antigenic structure type used for detection, and the cut-off for seropositivity. Here, we review the different BKPyV VP1 antigens types used for detection and consider the various BKPyV serostatus assay techniques' advantages and disadvantages. Lastly, we highlight the obstacles in the implementation of a consensual BKPyV serologic assay in clinics (e.g., the guidelines absence in this field).
Topics: BK Virus; DNA, Viral; Graft Rejection; Humans; Immunosuppression Therapy; Kidney Transplantation; Retrospective Studies; Serologic Tests; Transplant Recipients; Tumor Virus Infections; Viremia
PubMed: 31615131
DOI: 10.3390/v11100945 -
Reviews in Medical Virology Jul 2019BK polyomavirus (BKV) is an important cause of graft loss in renal transplant recipients that continues to pose a significant challenge to clinicians due to its... (Review)
Review
BK polyomavirus (BKV) is an important cause of graft loss in renal transplant recipients that continues to pose a significant challenge to clinicians due to its frequently unpredictable onset, persistence, and the lack of effective antiviral agents or prevention strategies. This review covers our current understanding of epidemiology, viral transmission and disease progression, and treatment and prevention strategies that have been used to manage this disease.
Topics: BK Virus; Disease Progression; Disease Transmission, Infectious; Humans; Immunocompromised Host; Immunosuppressive Agents; Kidney Transplantation; Polyomavirus Infections
PubMed: 30958614
DOI: 10.1002/rmv.2044 -
Acta Medica (Hradec Kralove) 2022All renal transplant recipients should undergo a regular screening for BK viral (BKV) viremia. Gradual reduction of immunosuppression is recommended in patients with...
All renal transplant recipients should undergo a regular screening for BK viral (BKV) viremia. Gradual reduction of immunosuppression is recommended in patients with persistent plasma BKV viremia for 3 weeks after the first detection, reflecting the presence of probable or suspected BKV-associated nephropathy. Reduction of immunosuppression is also a primary intervention in biopsy proven nephropathy associated with BKV (BKVN). Thus, allograft biopsy is not required to treat patients with BKV viremia with stabilized graft function. There is a lack of proper randomised clinical trials recommending treatment in the form of switching from tacrolimus to cyclosporin-A, from mycophenolate to mTOR inhibitors or leflunomide, or the additive use of intravenous immunoglobulins, leflunomide or cidofovir. Fluoroquinolones are not recommended for prophylaxis or therapy. There are on-going studies to evaluate the possibility of using a multi-epitope anti-BKV vaccine, administration of BKV-specific T cell immunotherapy, BKV-specific human monoclonal antibody and RNA antisense oligonucleotides. Retransplantation after allograft loss due to BKVN can be successful if BKV viremia is definitively removed, regardless of allograft nephrectomy.
Topics: Humans; Kidney Transplantation; Leflunomide; BK Virus; Viremia; Kidney Diseases; Immunosuppressive Agents; Polyomavirus Infections
PubMed: 36942701
DOI: 10.14712/18059694.2023.1 -
Transplantation Nov 2016BK polyomavirus is ubiquitous, with a seropositivity rate of over 75% in the adult population. Primary infection is thought to occur in the respiratory tract, but... (Review)
Review
BK polyomavirus is ubiquitous, with a seropositivity rate of over 75% in the adult population. Primary infection is thought to occur in the respiratory tract, but asymptomatic BK virus latency is established in the urothelium. In immunocompromised host, the virus can reactivate but rarely compromises kidney function except in renal grafts, where it causes a tubulointerstitial inflammatory response similar to acute rejection. Restoring host immunity against the virus is the cornerstone of treatment. This review covers the virus-intrinsic features, the posttransplant microenvironment as well as the host immune factors that underlie the pathophysiology of polyomavirus-associated nephropathy. Current and promising therapeutic approaches to treat or prevent this complication are discussed in relation to the complex immunopathology of this condition.
Topics: BK Virus; Dendritic Cells; Humans; Immunity, Innate; Kidney Diseases; Kidney Transplantation; Polyomavirus Infections; Risk Factors; Tumor Virus Infections; Viral Proteins; Virus Activation; Virus Latency
PubMed: 27391196
DOI: 10.1097/TP.0000000000001333 -
Journal of Clinical Virology : the... Oct 2015BK virus (BKV) causes BKV nephritis in renal transplant patients and contributes significantly to the increase of probability of graft loss. BKV, being latent in the... (Review)
Review
BK virus (BKV) causes BKV nephritis in renal transplant patients and contributes significantly to the increase of probability of graft loss. BKV, being latent in the urogenital tract, is likely to be transported with the donor kidney to recipients and following reactivation replicates in the nucleus of renal epithelial tubular cells. BKV daughter viruses are released and enter other renal epithelial cells to spread infection. There are still a lot of unknown factors about the mechanism and kinetics of BKV infection. The treatment of BKV infection, with exception of reduction in immunosuppression which increases the risk of allograft rejection, is almost exclusively limited to application of anti-viral drugs with rather inconsistent results. The shortcomings of anti-viral therapies demand the understanding of early steps of infection of permissive cells by BK virus in hope that adequate interventional therapies preventing infection of cells with BK virus could be developed. This review describes the BKV entry in target human cells, intracellular trafficking pathways of BKV particles and potential therapeutic implications based on understanding of mechanisms of BKV infection of renal cells.
Topics: Antiviral Agents; BK Virus; Epithelial Cells; Humans; Virus Internalization
PubMed: 26295751
DOI: 10.1016/j.jcv.2015.08.003 -
The Journal of Histochemistry and... May 2020BK polyomavirus-associated nephropathy (BKpyVAN) remains a cause of graft loss in kidney transplant recipients on immunosuppressive therapy. Its diagnosis relies on the...
BK polyomavirus-associated nephropathy (BKpyVAN) remains a cause of graft loss in kidney transplant recipients on immunosuppressive therapy. Its diagnosis relies on the identification of BK virus (BKV) in the renal allograft biopsy by positive immunohistochemical (IHC) stain for the viral SV40 large T antigen, although in situ hybridization (ISH) for viral DNA is used in some centers. We examined tissue detection of BKV RNA by RNAscope, a novel, automated ISH test, in 61 allograft biopsies from 56 patients with BKpyVAN. We found good correlation between the estimate of BKV tissue load by RNAscope ISH and SV40 IHC ( = 0.65, 0.0001). RNAscope ISH showed 88% sensitivity and 79% specificity and, as an alternative test, could confirm the presence of BKV tissue in presumed BKpyVAN and rule out BKV as the causative agent in JC virus nephropathy. We also used tissue BK viral load estimates by both RNAscope ISH and SV40 IHC to examine the relation between tissue and plasma BK levels and found significant correlation only between BK viremia and tissue BK measured by RNAscope ISH. Our findings suggest that the RNAscope ISH assay could be a reliable test for BKV detection in allograft biopsies.
Topics: BK Virus; Biopsy; Cohort Studies; DNA, Viral; Female; Humans; Kidney; Kidney Transplantation; Male; Middle Aged; Transplantation, Homologous
PubMed: 32352851
DOI: 10.1369/0022155420922604 -
International Journal of Molecular... Dec 2023Polyomaviruses are widespread, with BK viruses being most common in humans who require immunosuppression due to allotransplantation. Infection with BK polyomavirus (BKV)...
Polyomaviruses are widespread, with BK viruses being most common in humans who require immunosuppression due to allotransplantation. Infection with BK polyomavirus (BKV) may manifest as BK virus-associated nephropathy and hemorrhagic cystitis. Established diagnostic methods include the detection of polyomavirus in urine and blood by PCR and in tissue biopsies via immunohistochemistry. In this study, 79 patients with pathological renal retention parameters and acute kidney injury (AKI) were screened for BK polyomavirus replication by RNA extraction, reverse transcription, and virus-specific qPCR in urine sediment cells. A short fragment of the VP2 coding region was the target of qPCR amplification; patients with (n = 31) and without (n = 48) a history of renal transplantation were included. Urine sediment cell immunofluorescence staining for VP1 BK polyomavirus protein was performed using confocal microscopy. In 22 patients with acute renal injury, urinary sediment cells from 11 participants with kidney transplantation (KTX) and from 11 non-kidney transplanted patients (nonKTX) were positive for BK virus replication. BK virus copies were found more frequently in patients with AKI stage III (n = 14). Higher copy numbers were detected in KTX patients having experienced BK polyoma-nephropathy (BKPyVAN) in the past or diagnosed recently by histology (5.6 × 10-3.1 × 10). One patient developed BK viremia following delayed graft function (DGF) with BK virus-positive urine sediment. In nonKTX patients with BK copies, decoy cells were absent; however, positive staining of cells was found with epithelial morphology. Decoy cells were only found in KTX patients with BKPyVAN. In AKI, damage to the tubular epithelium itself may render the epithelial cells more permissive for polyoma replication. This non-invasive diagnostic approach to assess BK polyomavirus replication in urine sediment cells has the potential to identify KTX patients at risk for viremia and BKPyVAN during AKI. This method might serve as a valuable screening tool for close monitoring and tailored immunosuppression decisions.
Topics: Humans; BK Virus; Viremia; Kidney Transplantation; Kidney; Polyomavirus; Polyomavirus Infections; Acute Kidney Injury
PubMed: 38139342
DOI: 10.3390/ijms242417511