High frequency of Merkel cell polyomavirus DNA in the urine of kidney transplant recipients and healthy controls

Merkel cell polyomavirus and its etiological relationship with skin tumors

Viruses have been frequently identified in several human neoplasms, but the etiological role of these viruses in some tumors is still a matter of controversy. Polyomaviruses stand out among the main viruses with oncogenic capacity, specifically the Merkel cell polyomavirus (MCPyV). Recent revisions in the taxonomy of polyomaviruses have divided the Polyomaviridae family into six genera, including 117 species, with a total of 14 currently known human-infecting species. Although the oncogenicity of polyomaviruses has been widely reported in the literature since 1950, the first description of a polyomavirus as an etiological agent of a neoplasm in humans was made only in 2008 with the description of MCPyV, present in approximately 80% of cases of Merkel cell carcinoma (MCC), with the integration of its genome to that of the tumor cells and tumor-specific mutations, and it is considered the etiological agent of this neoplasm since then. MCPyV has also been detected in keratinocyte carcinomas, such as basal cell carcinoma and squamous cell carcinoma of the skin in individuals with and without immunosuppression. Data on the occurrence of oncogenic viruses potentially involved in oncogenesis, which cause persistence and tissue injury, related to the Merkel cell polyomavirus are still scarce, and the hypothesis that the Merkel cell polyomavirus may play a relevant role in the genesis of other cutaneous carcinomas in addition to MCC remains debatable. Therefore, the present study proposes to explore the current knowledge about the presence of MCPyV in keratinocyte carcinomas.

Translating genomic exploration of the family Polyomaviridae into confident human polyomavirus detection

The Polyomaviridae is a family of ubiquitous dsDNA viruses that establish persistent infection early in life. Screening for human polyomaviruses (HPyVs), which comprise 14 diverse species, relies upon species-specific qPCRs whose validity may be challenged by accelerating genomic exploration of the virosphere. Using this reasoning, we tested 64 published HPyV qPCR assays in silico against the 1781 PyV genome sequences that were divided in targets and nontargets, based on anticipated species specificity of each qPCR. We identified several cases of problematic qPCR performance that were confirmed in vitro and corrected through using degenerate oligos. Furthermore, our study ranked 8 out of 52 tested BKPyV qPCRs as remaining of consistently high quality in the wake of recent PyV discoveries and showed how sensitivity of most other qPCRs could be rescued by annealing temperature adjustment. This study establishes an efficient framework for ensuring confidence in available HPyV qPCRs in the genomic era.

From Merkel Cell Polyomavirus Infection to Merkel Cell Carcinoma Oncogenesis

Merkel cell polyomavirus (MCPyV) infection causes near-ubiquitous, asymptomatic infection in the skin, but occasionally leads to an aggressive skin cancer called Merkel cell carcinoma (MCC). Epidemiological evidence suggests that poorly controlled MCPyV infection may be a precursor to MCPyV-associated MCC. Clearer understanding of host responses that normally control MCPyV infection could inform prophylactic measures in at-risk groups. Similarly, the presence of MCPyV in most MCCs could imbue them with vulnerabilities that-if better characterized-could yield targeted intervention solutions for metastatic MCC cases. In this review, we discuss recent developments in elucidating the interplay between host cells and MCPyV within the context of viral infection and MCC oncogenesis. We also propose a model in which insufficient restriction of MCPyV infection in aging and chronically UV-damaged skin causes unbridled viral replication that licenses MCC tumorigenesis.

Human polyomaviruses genomes in clinical specimens of colon cancer patients

Colon cancer is the third cause of cancer death in the developed countries. Some environmental factors are involved in its pathogenesis, including viral infections. The possible involvement of human polyomaviruses (HPyVs) in colon cancer pathogenesis has been previously reported, leading to inconsistent conclusions. Clinical specimens were collected from 125 colon cancer patients. Specifically, 110 tumor tissues, 55 negative surgical margins, and 39 peripheral blood samples were analyzed for the presence of six HPyVs: JC polyomavirus (JCPyV), BK polyomavirus (BKPyV), Merkel cell PyV (MCPyV), HPyV -6, -7, and -9 by means of DNA isolation and subsequent duplex Real Time quantitative polymerase chain reaction. HPyVs genome was detected in 33/204 samples (16.2%): the significant higher positivity was found in tumor tissues (26/110, 23.6%), followed by negative surgical margins (3/55, 5.5%, p < .05), and peripheral blood mononuclear cells (PBMCs) (4/39; 10.3%). HPyVs load was statistically higher only in the tumor tissues compared to negative surgical margins (p < .05). Specifically, MCPyV was detected in 19.1% (21/110) of tumor tissues, 3.6% (2/55) of negative surgical margins (p < .05), and 7.7% (3/39) of PBMCs; HPyV-6 in 2.7% (3/110) of tumor tissues, and 1.8% (1/55) of negative surgical margins; one tumor tissue (1/110, 0.9%) and one PBMCs sample (1/39, 2.6%) were positive for BKPyV; JCPyV was present in 0.9% (1/110) of tumor tissues. HPyV-7 and 9 were not detected in any sample. High prevalence and load of MCPyV genome in the tumor tissues might be indicative of a relevant rather than bystander role of the virus in the colon tumorigenesis.

Viral Genomic Characterization and Replication Pattern of Human Polyomaviruses in Kidney Transplant Recipients

Human Polyomavirus (HPyV) infections are common, ranging from 60% to 100%. In kidney transplant (KTx) recipients, HPyVs have been associated with allograft nephropathy, progressive multifocal leukoencephalopathy, and skin cancer. Whether such complications are caused by viral reactivation or primary infection transmitted by the donor remains debated. This study aimed to investigate the replication pattern and genomic characterization of BK Polyomavirus (BKPyV), JC Polyomavirus (JCPyV), and Merkel Cell Polyomavirus (MCPyV) infections in KTx. Urine samples from 57 KTx donor/recipient pairs were collected immediately before organ retrieval/transplant and periodically up to post-operative day 540. Specimens were tested for the presence of BKPyV, JCPyV, and MCPyV genome by virus-specific Real-Time PCR and molecularly characterized. HPyVs genome was detected in 49.1% of donors and 77.2% of recipients. Sequences analysis revealed the archetypal strain for JCPyV, TU and Dunlop strains for BKPyV, and IIa-2 strain for MCPyV. VP1 genotyping showed a high frequency for JCPyV genotype 1 and BKPyV genotype I. Our experience demonstrates that after KTx, HPyVs genome remains stable over time with no emergence of quasi-species. HPyVs strains isolated in donor/recipient pairs are mostly identical, suggesting that viruses detected in the recipient may be transmitted by the allograft.

Molecular evolution pattern of Merkel cell polyomavirus identified by viral metagenomics in plasma of high-risk blood donors from the Brazilian Amazon

Merkel cell polyomavirus (MCPyV) is a common human skin pathogen, shows high seroprevalence and is considered the etiologic agent of Merkel cell carcinoma. However, studies which detect MCPyV DNA in blood products may reveal the importance of this virus for the transfusion medicine. In this study we analyzed by viral metagenomics 36 plasma samples obtained from blood donors positive for the common blood transmitted infections from the city of Macapá (Brazilian Amazon). The generated raw data were were analyzed through a specific bioinformatics pipeline aimed at discovery of emerging viruses. The genomes of interest were analyzed phylogeographically and phylogenetically. MCPyV complete genome was recovered from one HBV-positive pool with high coverage (~ 223×) indicating acute viremia or reactivated infection. Interestingly, the phylogeographic position of the identified strain suggests its ancestry compared to MCPyV isolate from Colombian Amazon which hypothesizes that viral dissemination in the Amazon may have originated from Brazil. In conclusion, this study brings information for the genetic relationships of MCPyV isolated from blood donors from the Brazilian Amazon and demonstrates the possible phylogeographic behavior of our strain in relation to the other findings. We also demonstrated a strong evidence of viremic MCPyV phase in blood donations, however, more studies are necessary in order to understand the MCPyV impact on transfusion therapy.

Merkel Cell Polyomavirus (MCPyV) in the Context of Immunosuppression: Genetic Analysis of Noncoding Control Region (NCCR) Variability among a HIV-1-Positive Population

Background: Since limited data are available about the prevalence of Merkel cell polyomavirus (MCPyV) and the genetic variability of its noncoding control region (NCCR) in the context of immunosuppression, this study aimed to investigate the distribution of MCPyV in anatomical sites other than the skin and the behavior of NCCR among an HIV-1-positive population. Methods: Urine, plasma, and rectal swabs specimens from a cohort of 66 HIV-1-positive patients were collected and subjected to quantitative real-time polymerase chain reaction (qPCR) for MCPyV DNA detection. MCPyV-positive samples were amplified by nested PCR targeting the NCCR, and NCCRs alignment was carried out to evaluate the occurrence of mutations and to identify putative binding sites for cellular factors. Results: MCPyV DNA was detected in 10/66 urine, in 7/66 plasma, and in 23/66 rectal samples, with a median value of 5 × 10² copies/mL, 1.5 × 10² copies/mL, and 2.3 × 10³ copies/mL, respectively. NCCR sequence analysis revealed a high degree of homology with the MCC350 reference strain in urine, whereas transitions, transversions, and single or double deletions were observed in plasma and rectal swabs. In these latter samples, representative GTT and GTTGA insertions were also observed. Search for putative binding sites of cellular transcription factors showed that in several strains, deletions, insertions, or single base substitutions altered the NCCR canonical configuration. Conclusions: Sequencing analysis revealed the presence of numerous mutations in the NCCR, including insertions and deletions. Whether these mutations may have an impact on the pathogenic features of the virus remains to be determined. qPCR measured on average a low viral load in the specimens analyzed, with the exception of those with the GTTGA insertion.

Merkel cell polyomavirus DNA sequences in the blood of healthy population of Pakistan

Aim: This study aimed at detecting and quantifying Merkel cell polyomavirus (MCPyV) viral loads in the peripheral blood of healthy Pakistani individuals. Patients & methods: A total of 221 whole blood samples obtained from healthy individuals were examined by qPCR. Results & conclusion: MCPyV was detected in the peripheral blood of 31.2% healthy individuals. The rate of MCPyV positivity decreased from young (36%), to middle (33.7%) and elder (25.3%) age groups. Our data revealed higher prevalence of MCPyV in women (43.93%) than men (25.80%). The MCPyV viral load was calculated in the range of 0.06 -11 copies/ng of isolated DNA. The MCPyV viral load increased from young (median = 3.35) to elder (median = 5.66) age groups. The MCPyV circulate at a higher frequency by residing dormant in certain blood cells, which might act as potential vehicles for the spread of MCPyV infection among general population.

Particulate matter exposure increases JC polyomavirus replication in the human host

BACKGROUND

Human polyomaviruses (HPyVs) asymptomatically infect the human population during childhood and establish latency in the host. Viral reactivation and urinary excretion can occur when the immune system is impaired. Exposure to particulate air pollution, including the PM₁₀/PM_2.5 components, is a public health problem and has been linked to several disorders. Studies assessing the relationship between PM₁₀/PM_2.5 exposure and viral replication are lacking.

OBJECTIVES

To investigate the relationship between HPyVs viruria and PM₁₀/PM_2.5 exposures.

METHODS

Individual environmental exposure was assessed in 50 healthy adult volunteers using a chemical transport model (CTM) with a municipality resolution for daily PM₁₀ and monitoring stations data for daily PM_2.5 exposures. For each subject, a urine sample was collected, and HPyVs (JCPyV, BKPyV, MCPyV, HPyV6, HPyV7 and HPyV9) loads were determined. Zero-inflated negative binomial (ZINB) regression was used to model the count data, as it contained excessive zeros. Covariates were chosen by stepwise selection.

RESULTS

HPyVs DNA was detected in 54% (median:87.6*10⁵ copies/ml) of the urine samples. JCPyV was the prevalent (48%, (median viral load:126*10⁵ copies/ml). Considering the load of the most frequently measured HPyVs, JCPyV, in the count-part of the ZINB model, every unitary in PM measured 2 days before urine collection (PM Day -2) was associated with an increase in JCPyV load (PM₁₀: +4.0%, p-value = 0.002; PM_2.5: +3.6%, p-value = 0.005). In the zero-part, the significant predictor was the PM₁₀ measured 5 days before urine collection (+3%, p-value = 0.03).

CONCLUSIONS

The environmental levels of PM₁₀/PM_2.5 increase the JCPyV viruria. Our findings emphasize the need for studies assessing the influence of air pollution exposure on the risk of viral reactivation.

Antibody response to polyomavirus primary infection: high seroprevalence of Merkel cell polyomavirus and lymphoid tissue involvement

Human polyomaviruses (HPyVs) asymptomatically infect the human population establishing latency in the host, and their seroprevalence can reach 90% in healthy adults. Few studies have focused on the pediatric population, and there are no reports regarding the seroprevalence of all the newly isolated HPyVs among Italian children. Therefore, we investigated the frequency of serum antibodies against 12 PyVs in 182 immunocompetent children from Northeast Italy, by means of a multiplex antibody detection system. Additionally, secondary lymphoid tissues were collected to analyze the presence of HPyV DNA sequences using a specific real-time PCRs or PCRs. Almost 100% of subjects were seropositive for at least one PyV. Seropositivity ranged from 3% for antibodies against simian virus 40 (SV40) in children from 0 to 3 years, to 91% for antibodies against WU polyomavirus (WUPyV) and HPyV10 in children from 8 to 17 years. The mean number of PyV for which children were seropositive increased with the increasing of age: 4 standard deviations (SD) 1.8 in the 0-3-year group, 5 (SD 1.9) in the 4-7-year group, and 6 (SD 2.2) in the 8-17-year group. JC polyomavirus (JCPyV) DNA was detected in 1% of the adenoids, WUPyV in 12% of the tonsils, and 28% of the adenoids, and Merkel cell polyomavirus (MCPyV) was present in 6 and 2% of the tonsils and adenoids, respectively. Our study gives new insights on the serological evidence of exposure to PyVs during childhood, and on their possible respiratory route of transmission.

Proceedings of the NASHNP Companion Meeting, March 18th, 2018, Vancouver, BC, Canada: Salivary Neuroendocrine Carcinoma-An Overview of a Rare Disease with an Emphasis on Determining Tumor Origin

Salivary neuroendocrine carcinomas are rare and the overwhelming majority is high-grade. The parotid gland is the most commonly involved site followed by the submandibular gland. Most arise de novo but rare examples occurring as a high-grade transformation of another type of salivary gland neoplasm exist. There is significant morphologic and immunophenotypic overlap with neuroendocrine carcinomas of other sites, especially the skin. Like cutaneous neuroendocrine (or Merkel cell) carcinomas, approximately three-fourths are cytokeratin 20 positive. Cytokeratin 20 positive salivary neuroendocrine carcinomas are often referred to as being of the 'Merkel cell type' since most other non-cutaneous neuroendocrine carcinomas are cytokeratin 20 negative. Salivary neuroendocrine carcinomas may be challenging to separate from Merkel cell carcinomas of the head and neck on pathologic grounds because the latter often metastasize to the parotid gland. Clinical history is often relied upon to separate primary salivary tumors from cutaneous metastases but may not be helpful in all cases. Here we review the clinical, pathologic and molecular features of salivary neuroendocrine carcinomas focusing on high-grade major salivary gland tumors. The difficulty in separating salivary tumors from metastatic Merkel cell carcinoma will be highlighted.

Merkel cell polyomavirus DNA in the blood of patients with neurological diseases and healthy controls

Aim: Merkel cell polyomavirus (MCPyV) is the etiological agent of Merkel cell carcinoma. Its genome has been detected in anatomic districts from healthy and ill subjects. Data regarding the MCPyV DNAemia in neurological patients are lacking. Materials & methods: Blood was obtained from 129 neurological patients and 181 controls (HIV positive or negative). Real-time polymerase chain reaction (Q-PCR) was conducted to quantify MCPyV loads in blood specimens. Results: MCPyV DNA was detected in 17.1% of cases and 11.0% of controls in <1% of cells. No association between MCPyV DNA presence and HIV status was observed. Conclusion: Blood cells may be a reservoir for MCPyV. The presence of MCPyV genome in blood of healthy subjects might be relevant for transfusion medicine.

T cell therapies for human polyomavirus diseases

Rapid restoration of virus-specific T immunity via adoptive transfer of ex vivo generated T cells has been proven as a powerful therapy for patients with advanced cancers and refractory viral infections such as cytomegalovirus (CMV) and Epstein-Barr virus (EBV). BK virus (BKV), John Cunningham virus (JCV), and Merkel cell carcinoma virus (MCV) are the members of the rapidly growing human polyomavirus (hPyV) family that commonly infects most healthy humans. These viruses have a clearly established potential for causing severe end-organ damage or malignant transformation, especially in individuals with weakened immunity who are unable to mount or regain endogenous T-cell responses as a result of underlying leukemia or iatrogenic immunosuppression in autoimmunity, bone marrow and solid organ transplant settings. Here we will discuss recent advances in using T-cell-based immunotherapies to save patients suffering from PyV-associated diseases including hemorrhagic cystitis, BKV virus-associated nephropathy, and JC-associated progressive multifocal leukoencephalopathy (PML). We will also review progress in the understanding of Merkel cell carcinoma (MCC) as a virally driven tumor that is amenable to immune intervention and can be targeted with adoptively transferred T cells specific for viral oncoproteins.

Polyomaviruses

Over the last 10 years, the number of identified polyomaviruses has grown to more than 35 subtypes, including 13 in humans. The polyomaviruses have similar genetic makeup, including genes that encode viral capsid proteins VP1, 2, and 3 and large and small T region proteins. The T proteins play a role in viral replication and have been implicated in viral chromosomal integration and possible dysregulation of growth factor genes. In humans, the Merkel cell polyomavirus has been shown to be highly associated with integration and the development of Merkel cell cancers. The first two human polyomaviruses discovered, BKPyV and JCPyV, are the causative agents for transplant-related kidney disease, BK commonly and JC rarely. JC has also been strongly associated with the development of progressive multifocal leukoencephalopathy (PML), a rare but serious infection in untreated HIV-1-infected individuals and in other immunosuppressed patients including those treated with monoclonal antibody therapies for autoimmune diseases systemic lupus erythematosus, rheumatoid arthritis, or multiple sclerosis. The trichodysplasia spinulosa-associated polyomavirus (TSAPyV) may be the causative agent of the rare skin disease trichodysplasia spinulosa. The remaining nine polyomaviruses have not been strongly associated with clinical disease to date. Antiviral therapies for these infections are under development. Antibodies specific for each of the 13 human polyomaviruses have been identified in a high percentage of normal individuals, indicating a high rate of exposure to each of the polyomaviruses in the human population. PCR methods are now available for detection of these viruses in a variety of clinical samples.

Frequent detection of Merkel cell polyomavirus DNA in tissues from 10 consecutive autopsies

Merkel cell polyomavirus (MCPyV) has been identified in samples of Merkel cell carcinoma (MCC), an aggressive skin cancer. Seroepidemiologic studies indicated a high frequency of MCPyV infection in humans, suggesting respiratory and faecal-oral routes, or transmission by skin contact. Since MCC is more frequent in immunocompromised patients, a reactivation of MCPyV latently infecting target cells has been proposed. However, neither definite ways of transmission nor specific target organs have been identified with certainty. Ten autopsies with an extensive organ sampling for a total of 121 specimens (tissue and blood samples) were collected. All tissue specimens were fixed in formalin and embedded in paraffin. Real-time PCR was performed to quantify the copy number of the large T antigen (LT) gene and the capsid VP1 gene of MCPyV. MCPyV LT and/or VP genes were detected in all of the collected specimens. A high prevalence of MCPyV was found in the blood (six cases) and lung (five cases); the brain was positive in three cases. The highest viral copy number was detected in blood from two autopsies (21 610 570.09 copies per 105 cells and 380 413.25 copies per 105 cells), whereas the viral copy number in the other organs was low. Our data confirm the high frequency of MCPyV infection in the general population, which seems to indicate that the respiratory tract is a possible route for viral transmission and viral persistence in the brain. The frequent detection of MCPyV DNA in blood suggests that circulating leukocytes could be one of the reservoirs of MCPyV, whereas the high viral copy number also seems to indicate the possibility of viral reactivation in immunocompetent adults.

Human polyomavirus: Advantages and limitations as a human-specific viral marker in aquatic environments

Human polyomaviruses (HPyVs) cause persistent infections in organs such as kidney, brain, skin, liver, respiratory tract, etc., and some types of HPyV are constantly excreted in the urine and/or feces of infected and healthy individuals. The use of an enteric virus as an indicator for human sewage/waste contamination in aquatic environments has been proposed; HPyVs are a good candidate since they are routinely found in environmental water samples from different geographical areas with relatively high abundance. HPyVs are highly human specific, having been detected in human waste from all age ranges and undetected in animal waste samples. In addition, HPyVs show a certain degree of resistance to high temperature, chlorine, UV, and low pH, with molecular signals (i.e., DNA) persisting in water for several months. Recently, various concentration methods (electronegative/positive filtration, ultrafiltration, skim-milk flocculation) and detection methods (immunofluorescence assay, cell culture, polymerase chain reaction (PCR), integrated cell culture PCR (ICC-PCR), and quantitative PCR) have been developed and demonstrated for HPyV, which has enabled the identification and quantification of HPyV in various environmental samples, such as sewage, surface water, seawater, drinking water, and shellfish. In this paper, we summarize these recent advancements in detection methods and the accumulation of environmental surveillance and laboratory-scale experiment data, and discuss the potential advantages as well as limitations of HPyV as a human-specific viral marker in aquatic environments.

Detection of Recently Discovered Human Polyomaviruses in a Longitudinal Kidney Transplant Cohort

A large number of human polyomaviruses have been discovered in the last 7 years. However, little is known about the clinical impact on vulnerable immunosuppressed patient populations. Blood, urine, and respiratory swabs collected from a prospective, longitudinal adult kidney transplant cohort (n = 167) generally pre-operatively, at day 4, months 1, 3, and 6 posttransplant, and at BK viremic episodes within the first year were screened for 12 human polyomaviruses using real-time polymerase chain reaction. Newly discovered polyomaviruses were most commonly detected in the respiratory tract, with persistent shedding seen for up to 6 months posttransplant. Merkel cell polyomavirus was the most common detection, but was not associated with clinical symptoms or subsequent development of skin cancer or other skin abnormalities. In contrast, KI polyomavirus was associated with respiratory disease in a subset of patients. Human polyomavirus 9, Malawi polyomavirus, and human polyomavirus 12 were not detected in any patient samples.

Merkel cell polyomavirus, a highly prevalent virus with tumorigenic potential

Merkel cell polyomavirus (MCPyV) is the only human polyomavirus known to be involved in tumorigenesis. Like other human polyomaviruses, MCPyV is highly prevalent in the healthy population, yet the MCPyV-associated Merkel cell carcinoma (MCC) is a very rare disease. Although in vitro and in vivo models have provided significant details regarding molecular functions of viral oncoproteins during cellular transformation, many open questions about the natural life cycle of the virus, its mechanisms of persistence and the precise role of MCPyV during MCC pathogenesis remain. This review will carve out the specifics of MCPyV biology and discuss unresolved issues to help the reader gain a better understanding of what may differentiate MCPyV from other polyomaviruses.

BK and JC virus infections in healthy patients compared to kidney transplant recipients in Tunisia

The human polyomaviruses BKPyV and JCPyV are members of Polyomaviridae family and after primary infections they persist as latent infection especially in the kidneys. BKVPy reactivation is mainly related to a renal nephropathy and JCV reactivation can induce the progressive multifocal leukoencephalopathy. The aim of this study was to investigate and to compare the presence of BKPyV and JCPyV in urine and plasma samples from immunocompromised and immunocompetent groups. The viral detection and quantification was done by a real time PCR from 100 healthy individuals and from 72 kidney transplanted patients (KTx) enrolled in a prospective study. Polyomavirus DNA urinary shedding was identified in 19% of healthy person, BKPyV in 6%; JCPyV more frequent in 13%. No individuals in this group developed polyomavirus viremia. BKPyV and JCPyV viruria was seen in 36% and 28% of KTx respectively, and 11% had a concomitant BKPyV and JCPyV viruria. Only BKPy viremia was detected in 5.5% of the KTx. In healthy persons, JCPyV shedding was associated with older individuals. However, in KTx, BKPyV was associated with younger age and male gender. No significant association was found between the patient's origin and BKPyV or JCPyV infection. In conclusion and consisting with previous reports, BKPyV and JCPyV prevalence and urinary loads were significantly higher in immunosuppressed compared to non-immunosuppressed individuals. In Addition and by contrast to KTx, JCPyV was more frequent than BKPyV in healthy individuals. Furthermore, the shedding of both polyomaviruses was differently associated with the age and the sex according to each population.

Significance, cytomorphology of decoy cells in polyomavirus-associated nephropathy: Review of clinical, histopathological, and virological correlates with commentary

Human polyomaviruses (PyV) are ubiquitous, remaining predominantly inactive hence asymptomatic in the healthy, immunocompetent population. BK and JC PyV potentially infect pan-urinary tract epithelial cells. With reactivation, PyV disrupt cell cycling mechanisms, facilitating viral replication leading to cell necrosis, exfoliation, and, infrequently, carcinogenesis. Exfoliated PyV-infected cells pose diagnostic pitfalls, hence they are termed "decoy cells" as they may mimic high-grade urothelial carcinoma cells. BK polyomavirus-associated-nephropathy (BKVAN) is an inflammatory disease causing interstitial fibrosis with tubular atrophy in renal transplant recipients, increasing risk of graft loss. BKVAN is confirmed by renal biopsy, and managed by immunosuppression modulation. As voided urine may provide pan-reno-urinary tract sampling, cytopathology may serve a critical diagnostic purpose coupled with decoy cell quantification and indirect BK PyV load gauging. Thus, identification of decoy cells and differentiation from high-grade urothelial carcinoma cells, and degenerated, benign urothelial cells, is clinically essential. PyV virology and pathobiology in the context of renal transplantation, immuno-suppression and BKVAN, and, decoy cell cytomorphology and cytopreparation with commentary are highlighted. Decoy cell overall characteristics: variable degeneration; cytomegaly; comet-like shapes; angular cytoplasmic extensions; eccentric, polar nuclear placements; moderate anisocytosis; typically single cells with high N:C ratios. Cytoplasmic features: moderate-abundance; granular, blue-gray monochromatism. Nuclear features: karyomegaly; haphazardly-scattered chromatin densities; smudged, homogeneous, basophilic ground glass masses displacing chromatin alongside inner periphery of regular, symmetrical nuclear envelopes. Background features: granular cellular debris; inflammatory cells; intact and lyzed erythrocytes. Decoy cells lack coarse chromatin as in high-grade urothelial carcinoma cells. Benign urothelial cells exhibit low N:C ratios with fine chromatin distribution and euchromasia.

Merkel cell carcinoma: Do you know your guidelines?

BACKGROUND

Merkel cell carcinoma (MCC) is a cutaneous neuroendocrine malignancy that exhibits clinically aggressive features and is associated with a poor prognosis. The incidence of MCC seems to be increasing for reasons unknown, and is estimated to be 0.32/100,000 in the United States.

METHODS

This article will review the current literature and National Comprehensive Cancer Network practice guidelines in the treatment of MCC.

RESULTS

Resection of MCC with negative margins remains the mainstay of therapy. Positive nodal disease should be treated with neck dissection and adjuvant radiotherapy. High-risk patients should undergo adjuvant radiotherapy, which improves oncologic outcomes. The role of chemotherapy is less clear and is currently reserved for advanced-stage MCC and palliative therapy.

CONCLUSION

The pathogenesis of MCC has recently been impacted with the discovery of the Merkel cell polyomavirus (MCPyV). Research to establish targeted and immunologic therapeutic options are ongoing.

First Detection of Human Papillomaviruses and Human Polyomaviruses in River Waters in Italy

Waterborne exposure to human viruses is possible through contact with contaminated water environments and can result in infections associated with a wide range of illnesses, including gastrointestinal, respiratory, ear, ocular, and skin infections. Recently, the occurrence in water environments of two groups of human viruses-both known with oncogenic potential, human polyomaviruses (HPyVs) and papillomaviruses (HPVs)-has been reported worldwide. These viruses, responsible for highly prevalent infections worldwide, have recently been proposed as potentially emerging waterborne pathogens. The objective of the present study was to examine the occurrence of HPyVs and HPVs in surface waters, by monitoring two rivers in Northwestern Italy, by nested PCR assays and sequencing. HPyVs (JC, BK, and Merkel cell polyomavirus) were detected in 10/25 (40%) samples. HPVs (HPV8, 17, 21, 25, 32, 80, 99, 105, and putative new HPVs) were identified in 14/25 (56%) river samples. The number of HPV DNA copies in waters was measured by quantitative real-time PCR. To our knowledge, this is the first detection and quantification of HPVs in surface waters. The possibility that HPyVs and HPVs can be transmitted by the waterborne route deserves to be explored in future studies.

Human herpesvirus-6 and polyomaviruses DNAemia in children and young adult patients after kidney transplantation

Aims: Human herpesvirus-6 (HHV-6) and polyomaviruses (HPyV) establish latency and reactivate in immunocompromised hosts. The prevalence of their infections was investigated in pediatric and young adult kidney transplant recipients. Materials & methods: Blood was obtained from 83 patients. Quantitative real-time polymerase chain reactions were conducted to quantify HHV-6 and HPyV loads; nested PCR and reverse transcriptase-PCR assays were conducted to differentiate HHV-6A from 6B and to evaluate the presence of transcripts. Results: HHV-6 and HPyV DNAemia were detected in 19.3 and 18.1% patients, respectively. No association between HHV-6 and HPyV DNA presence, age of patients and time from transplant was observed. Conclusion: HHV-6 infection in immunosuppression setting was as common as those of HPyVs that are commonly recognized as opportunistic agents.

First detection of papillomaviruses and polyomaviruses in swimming pool waters: unrecognized recreational water-related pathogens?

AIMS

Viral outbreaks associated with swimming pools have been described worldwide. The objective of this study was to examine the extent of viral contamination in indoor and outdoor swimming pools.

METHODS AND RESULTS

Pools were examined for the presence of human enteric viruses (adenovirus, norovirus and enterovirus) and nonenteric viruses (papillomavirus and polyomavirus-BK, JC, KI, WU and Merkel cell). Bacteriological parameters were also evaluated. The analysed pool waters met microbiological quality standards. Enteric viruses were not detected. On the other hand, papillomaviruses (HPV8, 12, 23, 25, 120 and unclassified HPVs) and polyomaviruses (JC and Merkel cell polyomaviruses) were detected in 9/14 samples (64%). The number of HPV DNA copies in pool waters, measured by quantitative Real-time PCR, ranged from 1.27E+04 to 1.13E+05/10L.

CONCLUSION

Results show that a variety of nonenteric viruses may be discharged in pool waters by various secretions and excretions from infected individuals or asymptomatic carriers.

SIGNIFICANCE AND IMPACT OF THE STUDY

To the best of our knowledge, this is the first report on human papillomaviruses and polyomaviruses in swimming pools. The likelihood that these viruses can be transmitted by recreational activities deserves to be explored in future studies.

Merkel cell carcinoma of the head and neck: pathogenesis, current and emerging treatment options

Merkel cell carcinoma (MCC) is a relatively uncommon, neuroendocrine, cutaneous malignancy that often exhibits clinically aggressive features and is associated with a poor prognosis. It typically presents as a painless, rapidly enlarging, dome-shaped red or purplish nodule in a sun-exposed area of the head and neck or upper extremities. Our understanding of MCC has increased dramatically over the last several years and the pathogenesis continues to be an area of active research. The etiology is likely multifactorial with immunosuppression, UV-induced skin damage, and viral factors contributing to the development of MCC. The recent discovery of Merkel cell polyomavirus has allowed for at least one aspect of disease development to be much better understood. In most cases, treatment consists of wide local excision with adjuvant radiation therapy. The role of chemotherapeutics is still being defined. The recent advancement of knowledge regarding the pathogenesis of MCC has led to an explosion research into novel therapeutic agents and strategies. This review seeks to summarize the current body of literature regarding the pathogenesis of MCC and potential targets for future therapies.

Early and late promoters of BK polyomavirus, Merkel cell polyomavirus, Trichodysplasia spinulosa-associated polyomavirus and human polyomavirus 12 are among the strongest of all known human polyomaviruses in 10 different cell lines

Recently, 11 new human polyomaviruses (HPyVs) have been isolated and named KI, WU, Merkel cell polyomavirus (MCPyV), HPyV6,  -7,  -9,  -10 and  -12, Trichodysplasia spinulosa-associated polyomavirus (TSPyV), STLPyV and NJPyV-2013. Little is known about cell tropism of the novel HPyVs, and cell cultures allowing virus propagation are lacking. Because viral tropism partially depends on the interaction of cellular transcription factors with the viral promoter, we monitored the promoter activity of all known HPyVs. Therefore, we compared the relative early and late promoter activity of the BK polyomavirus (BKPyV) (WW strain) with the corresponding activities of the other HPyVs in 10 different cell lines derived from brain, colon, kidney, liver, lung, the oral cavity and skin. Our results show that the BKPyV, MCPyV, TSPyV and HPyV12 early promoters displayed the strongest activity in most cell lines tested, while the remaining HPyV had relative low early promoter activity. HPyV12 showed the highest late promoter activity of all HPyVs in most cell lines, but also the BKPyV, MCPyV and TSPyV late promoters belonged to the stronger ones among HPyVs. The HPyVs with weak early promoter activity had in general also weak late promoter activity, except for HPyV10 whose late promoter was relatively strong in six of the 10 cell lines. A 20 bp deletion in the promoter of an HPyV12 variant significantly affected both early and late promoter activity in most cell lines. In conclusion, our findings suggest which cell lines may be suitable for virus propagation and may give an indication of the cell tropism of the HPyVs.