Discovery of a new human polyomavirus associated with trichodysplasia spinulosa in an immunocompromized patient

Trichodysplasia Spinulosa

Trichodysplasia spinulosa (TS) is a unique, rare clinical and histological dermatologic entity described mainly in a setting of immunosuppression. It is caused by a novel human polymoavirus, TS-associated polyomavirus. Reduction of immunosuppression and/or anti-viral therapy is the main therapeutic strategies used to treat such cases. We report a biopsy-proven case of TS in a male renal transplant patient who presented to a dermatology outpatient clinic in Montreal, Canada, in 2015. He was managed with valgancyclovir with no obvious response. Subsequently, a trial of topical imiquimod was commenced. Awareness of TS can prompt early diagnosis and management to prevent possible complications.

Phosphorylation of Human Polyomavirus Large and Small T Antigens: An Ignored Research Field

Protein phosphorylation and dephosphorylation are the most common post-translational modifications mediated by protein kinases and protein phosphatases, respectively. These reversible processes can modulate the function of the target protein, such as its activity, subcellular localization, stability, and interaction with other proteins. Phosphorylation of viral proteins plays an important role in the life cycle of a virus. In this review, we highlight biological implications of the phosphorylation of the monkey polyomavirus SV40 large T and small t antigens, summarize our current knowledge of the phosphorylation of these proteins of human polyomaviruses, and conclude with gaps in the knowledge and a proposal for future research directions.

Identification of a new polyomavirus in distinct human populations and tissues

Several human polyomaviruses (HPyVs) have been described in the last 15 years. This work aimed to characterize a novel HPyV with cutaneous tropism. Swabs of healthy skin (forehead) of 75 immunocompetent individuals from Argentina were screened for HPyV through sequence amplification techniques. Publicly available metagenomic data sets were also analyzed. A previously unknown polyomavirus sequence was detected in two skin swab samples. A nearly identical sequence was detected in public data sets representing metagenomic surveys of human skin and feces. Further analyses showed that the new polyomavirus diverges from its nearest relative, human polyomavirus 6 (HPyV6), by 17.3%-17.7% (in nucleotides for the large T antigen), which meets criteria for a new species designation in the genus Deltapolyomavirus. The screening also revealed more distant HPyV6 relatives in macaque genital and chimpanzee fecal data sets. Since polyomaviruses are generally thought to cospeciate with mammalian hosts, the high degree of similarity to HPyV6 suggests the new polyomavirus species is human-tropic. Therefore, a novel polyomavirus was identified and characterized from samples of distinct populations and tissues. We suggest the common name human polyomavirus 16 (HPyV16).

Mycosis Fungoides in Solid-Organ Transplant Recipients: A Multicenter Retrospective Cohort Study

BACKGROUND

Mycosis fungoides (MF) in solid-organ transplant recipients (SOTRs) is rare, with limited data on disease characteristics.

OBJECTIVE

The aim was to study the characteristics of MF in SOTRs with an emphasis on the immunosuppressive therapy.

METHODS

A retrospective cohort of patients diagnosed with MF, who were also SOTRs, were followed at 3 cutaneous lymphoma outpatient clinics, between January 2010 and February 2022.

RESULTS

Ten patients were included (7 male; median ages at transplantation and at diagnosis of MF were 33 and 48 years, respectively; 40% were diagnosed before the age of 18 years). Median time from transplantation to diagnosis of MF was 8 years (range 0.5-22). Transplanted organs and immunosuppressive treatments included: liver (n = 5; 4 treated with tacrolimus, 1 with tacrolimus and prednisone), kidney (n = 3), liver and kidney (n = 1), and heart (n = 1), all treated with mycophenolic acid, tacrolimus, and prednisone. Nine had early-stage MF (IA - 4, IB - 5; 40% with early folliculotropic MF), treated with skin-directed therapies, in 2 combined with acitretin, achieving partial/complete response. One patient had advanced-stage MF (IIIA) with folliculotropic erythroderma, treated with ultraviolet A and narrow-band ultraviolet B with acitretin, achieving partial response. Immunosuppression was modified in 3. At last follow-up (median 4 years, range 1-8), no stage progression was observed; 5 had no evidence of disease, 5 had active disease (IA/IB - 4, III - 1).

CONCLUSIONS

MF in SOTRs is usually diagnosed at an early stage, with overrepresentation of folliculotropic MF, and of children. Immunosuppressive therapy alterations, not conducted in most patients, should be balanced against the risk of organ compromise/rejection. Disease course was similar to MF in immunocompetent patients, during the limited time of follow-up.

Serology Identifies LIPyV as a Feline Rather than a Human Polyomavirus

The number of identified human polyomaviruses (HPyVs) has increased steadily over the last decade. Some of the novel HPyVs have been shown to cause disease in immunocompromised individuals. The Lyon-IARC polyomavirus (LIPyV) belonging to species Alphapolyomavirus quardecihominis was identified in 2017 in skin and saliva samples from healthy individuals. Since its initial discovery, LIPyV has rarely been detected in human clinical samples but has been detected in faeces from cats with diarrhoea. Serological studies show low LIPyV seroprevalence in human populations. To investigate the possibility that LIPyV is a feline rather than a human polyomavirus, we compared serum IgG responses against the VP1 major capsid protein of LIPyV and 13 other HPyVs among cats (n = 40), dogs (n = 38) and humans (n = 87) using an in-house immunoassay. Seropositivity among cats was very high (92.5%) compared to dogs (31.6%) and humans (2.3%). Furthermore, the median antibody titres against LIPyV were 100-10,000x higher in cats compared to dogs and humans. In conclusion, the high prevalence and intensity of measured seroresponses suggest LIPyV to be a feline rather than a human polyomavirus. Whether LIPyV infection induces diarrhoea or other symptoms in cats remains to be established.

Current treatments and emerging therapies of human polyomavirus-associated skin diseases: a comprehensive review

Since Merkel cell polyomavirus (MCPyV) was linked as the predominant etiology of Merkel cell carcinoma (MCC) in 2008, three additional human polyomaviruses (HPyV) have been definitively linked to cutaneous diseases-trichodysplasia spinulosa virus (TSPyV) and human polyomavirus 6 and 7 (HPyV6, HPyV7). TSPyV contributes to the development of trichodysplasia spinulosa (TS), and HPyV6/7 is associated closely with the eruption of pruritic and dyskeratotic dermatoses (PDD). Clinically, MCC is treated with surgical excision and radiation with adjuvant chemotherapy, although newer treatment options include immune checkpoint inhibition. These novel immunotherapies hold promise for the treatment of metastatic MCC, but resistance and side effects prevent a significant proportion of patients from realizing their benefits. Based on previous case reports, the standard of care for the less deadly but disfiguring cutaneous disease TS include immunosuppressant (IS) reduction, the use of antivirals such as cidofovir (CDV) or valganciclovir (VGCV), or a combination of these treatments. Similar treatments were attempted for PDD, but oral acitretin was found to be most effective. As MCC, TS, and PDD are rare diseases, further research is required for effective treatments. In this review, we summarize clinical trials, preclinical studies, and case reports that present outcomes and side effects of current and emerging treatments for HPyV-associated cutaneous diseases, offering a comprehensive resource for clinical application and prospective clinical trials.

JC polyomavirus: a short review of its biology, its association with progressive multifocal leukoencephalopathy, and the diagnostic value of different methods to manifest its activity or presence

INTRODUCTION

JC polyomavirus is the causative agent of progressive multifocal leukoencephalopathy (PML), a demyelinating disease resulting from the lytic infection of oligodendrocytes that may develop in immunosuppressed individuals: HIV1 infected or individuals under immunosuppressive therapies. Understanding the biology of JCPyV is necessary for a proper patient management, the development of diagnostic tests, and risk stratification.

AREAS COVERED

The review covers different areas of expertise including the genomic characterization of JCPyV strains detected in different body compartments (urine, plasma, and cerebrospinal fluid) of PML patients, viral mutations, molecular diagnostics, viral miRNAs, and disease.

EXPERT OPINION

The implementation of molecular biology techniques improved our understanding of JCPyV biology. Deep sequencing analysis of viral genomes revealed the presence of viral quasispecies in the cerebrospinal fluid of PML patients characterized by noncoding control region rearrangements and VP1 mutations. These neurotropic JCPyV variants present enhanced replication and an altered cell tropism that contribute to PML development. Monitoring these variants may be relevant for the identification of patients at risk of PML. Multiplex realtime PCR targeting both the LTAg and the archetype NCCR could be used to identify them. Failure to amplify NCCR should indicate the presence of a JCPyV prototype speeding up the diagnostic process.

Detection Analysis and Study of Genomic Region Variability of JCPyV, BKPyV, MCPyV, HPyV6, HPyV7 and QPyV in the Urine and Plasma of HIV-1-Infected Patients

Since it was clearly established that HIV/AIDS predisposes to the infection, persistence or reactivation of latent viruses, the prevalence of human polyomaviruses (HPyVs) among HIV-1-infected patients and a possible correlation between HPyVs and HIV sero-status were investigated. PCR was performed to detect and quantify JCPyV, BKPyV, MCPyV, HPyV6, HPyV7 and QPyV DNA in the urine and plasma samples of 103 HIV-1-infected patients. Subsequently, NCCR, VP1 and MCPyV LT sequences were examined. In addition, for MCPyV, the expression of transcripts for the LT gene was investigated. JCPyV, BKPyV and MCPyV's presence was reported, whereas HPyV6, HPyV7 and QPyV were not detected in any sample. Co-infection patterns of JCPyV, BKPyV and MCPyV were found. Archetype-like NCCRs were observed with some point mutations in plasma samples positive for JCPyV and BKPyV. The VP1 region was found to be highly conserved among these subjects. LT did not show mutations causing stop codons, and LT transcripts were expressed in MCPyV positive samples. A significant correlation between HPyVs' detection and a low level of CD4+ was reported. In conclusion, HPyV6, HPyV7 and QPyV seem to not have a clinical relevance in HIV-1 patients, whereas further studies are warranted to define the clinical importance of JCPyV, BKPyV and MCPyV DNA detection in these subjects.

Seroprevalence of Four Polyomaviruses Linked to Dermatological Diseases: New Findings and a Comprehensive Analysis

Our aim was to study the seroprevalence of human polyomaviruses (HPyV) linked to skin diseases. A total of 552 serum samples were analysed by the enzyme-linked immunosorbent assay to detect IgG antibodies against Merkel cell polyomavirus (MCPyV), HPyV6, HPyV7 and Trichodysplasia spinulosa-associated polyomavirus (TSPyV) using recombinant major capsid proteins of these viruses. The individuals (age 0.8−85 years, median 33) were sorted into seven age groups: <6, 6−10, 10−14, 14−21, 21−40, 40−60 and >60 years. The adulthood seroprevalence was 69.3%, 87.7%, 83.8% and 85% for MCPyV, HPyV6, HPyV7 and TSPyV, respectively. For all four polyomaviruses, there was increasing seropositivity with age until reaching the adulthood level. There was a significant increase in seroreactivity for those age groups in which the rate of already-infected individuals also showed significant differences. The adulthood seropositvity was relatively stable with ageing, except for TSPyV, for which elevated seropositivity was observed for the elderly (>60 years) age group. Since seroepidemiological data have been published with wide ranges for all the viruses studied, we performed a comprehensive analysis comparing the published age-specific seropositivities to our data. Although the cohorts, methods and even the antigens were variable among the studies, there were similar results for all studied polyomaviruses. For MCPyV, geographically distinct genotypes might exist, which might also result in the differences in the seroprevalence data. Additional studies with comparable study groups and methods are required to clarify whether there are geographical differences.

Deciphering the role of predicted miRNAs of polyomaviruses in carcinogenesis

Human polyomaviruses are relatively common in the general population. Polyomaviruses maintain a persistent infection after initial infection in childhood, acting as an opportunistic pathogen in immunocompromised populations and their association has been linked to carcinogenesis. A comprehensive understanding of the underlying molecular mechanisms of carcinogenesis in consequence of polyomavirus infection remains elusive. However, the critical role of viral miRNAs and their potential targets in modifying the transcriptome profile of the host remains largely unknown. Polyomavirus-derived miRNAs have the potential to play a substantial role in carcinogenesis. Employing computational approaches, putative viral miRNAs along with their target genes have been predicted and possible roles of the targeted genes in many significant biological processes have been obtained. Polyomaviruses have been observed to target intracellular signal transduction pathways through miRNA-mediated epigenetic regulation, which may contribute to cancer development. In addition, BKPyV-infected human renal cell microarray data was coupled with predicted target genes and analysis of the downregulated genes indicated that viruses target multiple signaling pathways (e.g. MAPK signaling pathway, PI3K-Akt signaling pathway, PPAR signaling pathway) in the host as well as turning off several tumor suppression genes (e.g. FGGY, EPHX2, CACNA2D3, CDH16) through miRNA-induced mechanisms, assuring cell transformation. This study provides a conceptual framework for the underlying molecular mechanisms involved in the course of carcinogenesis upon polyomavirus infection.

Skin Biopsy in Pediatric Oncology/Hematopoietic Stem Cell Transplantation Patients

ABSTRACT

The aim of this study was to review the dermatopathological findings in skin biopsy specimens from pediatric oncology and hematopoietic stem cell transplantation patients over a 20-year period. Three hundred fifty-two skin biopsies from 240 patients were reviewed, and the findings were grouped into 6 categories: index neoplasms, nonindex neoplasms, infections, graft-versus-host disease, other treatment complications, and others. Among the index neoplasms identified on skin biopsy, the most common conditions were Langerhans cell histiocytosis (14 patients) and melanoma (7 patients), with other hematological malignancies and an array of soft-tissue tumors accounting for the bulk of the remainder. Neoplastic conditions common in general dermatopathological practice such as basal cell carcinoma and squamous cell carcinoma were uncommon, each being identified in only 1 patient younger than the age of 18, although basal cell carcinomas developing subsequently in young adult life were identified in 7 patients. Infections were common, with infectious agents or viral cytopathic effects (not including human papillomavirus) identified in 34 biopsies. A significant proportion (74%) represented invasive fungal infections, which are of very significant clinical importance. Biopsies performed for a clinical suspicion of graft-versus-host seldom showed histological features to suggest an alternative diagnosis, with only a single case suggesting a diagnosis of toxic erythema of chemotherapy identified.

Lyon IARC Polyomavirus Displays Transforming Activities in Primary Human Cells

Several studies reported the presence of a recently discovered polyomavirus (PyV), Lyon IARC PyV (LIPyV), in human and domestic animal specimens. LIPyV has some structural similarities to well-established animal and human oncogenic PyVs, such as raccoon PyV and Merkel cell PyV (MCPyV), respectively. In this study, we demonstrate that LIPyV early proteins immortalize human foreskin keratinocytes. LIPyV LT binds pRb, accordingly cell cycle checkpoints are altered in primary human fibroblasts and keratinocytes expressing LIPyV early genes. Mutation of the pRb binding site in LT strongly affected the ability of LIPyV ER to induced HFK immortalization. LIPyV LT also binds p53 and alters p53 functions activated by cellular stresses. Finally, LIPyV early proteins activate telomerase reverse transcriptase (hTERT) gene expression, via accumulation of the Sp1 transcription factor. Sp1 recruitment to the hTERT promoter is controlled by its phosphorylation, which is mediated by ERK1 and CDK2. Together, these data highlight the transforming properties of LIPyV in in vitro experimental models, supporting its possible oncogenic nature. IMPORTANCE Lyon IARC PyV is a recently discovered polyomavirus that shows some structural similarities to well-established animal and human oncogenic PyVs, such as raccoon PyV and Merkel cell PyV, respectively. Here, we show the capability of LIPyV to efficiently promote cellular transformation of primary human cells, suggesting a possible oncogenic role of this virus in domestic animals and/or humans. Our study identified a novel virus-mediated mechanism of activation of telomerase reverse transcriptase gene expression, via accumulation of the Sp1 transcription factor. In addition, because the persistence of infection is a key event in virus-mediated carcinogenesis, it will be important to determine whether LIPyV can deregulate immune-related pathways, similarly to the well-established oncogenic viruses.

Small DNA tumor viruses and human cancer: Preclinical models of virus infection and disease

Human tumor viruses cause various human cancers that account for at least 15% of the global cancer burden. Among the currently identified human tumor viruses, two are small DNA tumor viruses: human papillomaviruses (HPVs) and Merkel cell polyomavirus (MCPyV). The study of small DNA tumor viruses (adenoviruses, polyomaviruses, and papillomaviruses) has facilitated several significant biological discoveries and established some of the first animal models of virus-associated cancers. The development and use of preclinical in vivo models to study HPVs and MCPyV and their role in human cancer is the focus of this review. Important considerations in the design of animal models of small DNA tumor virus infection and disease, including host range, cell tropism, choice of virus isolates, and the ability to recapitulate human disease, are presented. The types of infection-based and transgenic model strategies that are used to study HPVs and MCPyV, including their strengths and limitations, are also discussed. An overview of the current models that exist to study HPV and MCPyV infection and neoplastic disease are highlighted. These comparative models provide valuable platforms to study various aspects of virus-associated human disease and will continue to expand knowledge of human tumor viruses and their relationship with their hosts.

Complexities of JC Polyomavirus Receptor-Dependent and -Independent Mechanisms of Infection

JC polyomavirus (JCPyV) is a small non-enveloped virus that establishes lifelong, persistent infection in most of the adult population. Immune-competent patients are generally asymptomatic, but immune-compromised and immune-suppressed patients are at risk for the neurodegenerative disease progressive multifocal leukoencephalopathy (PML). Studies with purified JCPyV found it undergoes receptor-dependent infectious entry requiring both lactoseries tetrasaccharide C (LSTc) attachment and 5-hydroxytryptamine type 2 entry receptors. Subsequent work discovered the major targets of JCPyV infection in the central nervous system (oligodendrocytes and astrocytes) do not express the required attachment receptor at detectable levels, virus could not bind these cells in tissue sections, and viral quasi-species harboring recurrent mutations in the binding pocket for attachment. While several research groups found evidence JCPyV can use novel receptors for infection, it was also discovered that extracellular vesicles (EVs) can mediate receptor independent JCPyV infection. Recent work also found JCPyV associated EVs include both exosomes and secretory autophagosomes. EVs effectively present a means of immune evasion and increased tissue tropism that complicates viral studies and anti-viral therapeutics. This review focuses on JCPyV infection mechanisms and EV associated and outlines key areas of study necessary to understand the interplay between virus and extracellular vesicles.

Trichodysplasia spinulosa in a bone marrow transplant recipient: A case report

Trichodysplasia spinulosa is a rare skin condition seen in immunocompromised patients, especially in solid organ recipients. A recent review of the literature mentioned that there are 60 reported cases. We report a case in a patient with an allogenic bone marrow transplant. The patient developed white spiky protrusions on different areas of the face which improved after decreasing immunosuppression.

[Human polyomavirus-associated skin diseases]

Of the 15 currently known human polyomaviruses (HPyV), eight have been found on healthy skin. Merkel cell polyomavirus (MCPyV), HPyV6, HPyV7, and to a lesser extent Saint Louis polyomavirus (STLPyV) are considered part of the human cutaneous virome. The most important cutaneous polyomavirus, MCPyV, causes the majority of Merkel cell carcinomas (MCC). MCC is a rare but very aggressive malignant skin tumor that affects both immunocompetent and immunosuppressed patients. A steady increase in incidence rates of this skin tumor has been observed in recent decades. MCC occurs primarily on sunlight-exposed skin of fair-skinned individuals. Risk factors for MCC development include immunosuppression and advanced age. In immunocompromised individuals, primary infection with trichodysplasia spinulosa-associated polyomavirus (TSPyV) can cause the very rare skin disease trichodysplasia spinulosa (TS). Keratin spines (spicules), mainly in the center of the face, clinically characterize this disease. Skin lesions associated with further HPyV have been described exclusively in immunocompromised individuals. For HPyV6 and HPyV7, cases of epithelial proliferation and pruritic dyskeratotic dermatitis have been published. HPyV9 and New Jersey polyomavirus (NJPyV-13) were each found in different skin lesions of individual patients. The role of these polyomaviruses in the development of the skin lesions is still unclear.

Prevalence of MCPyV, HPyV6, HPyV7 and TSPyV in Actinic Keratosis Biopsy Specimens

To date, 14 human polyomaviruses (HPyVs) have been identified using high-throughput technologies. Among them, MCPyV, HPyV6, HPyV7 and TSPyV present a skin tropism, but a causal role in skin diseases has been established only for MCPyV as a causative agent of Merkel cell carcinoma (MCC) and TSPyV as an etiological agent of Trichodysplasia Spinulosa (TS). In the search for a possible role for cutaneous HPyVs in the development of skin malignant lesions, we investigated the prevalence of MCPyV, HPyV6, HPyV7 and TSPyV in actinic keratosis (AK), a premalignant skin lesion that has the potential to progress towards a squamous cell carcinoma (SCC). One skin lesion and one non-lesion skin from nine affected individuals were analyzed by qualitative PCR. MCPyV was detected in 9 out of 9 lesion biopsies and 6 out of 8 non-lesion biopsies. HPyV6 was detected only in healthy skin, while HPyV7 and TSPyV were not detected in any skin sample. These findings argue against a possible role of cutaneous HPyVs in AK. However, considering the small sample size analyzed, a definitive conclusion cannot be drawn. Longitudinal studies on large cohorts are warranted.

Functional Domains of the Early Proteins and Experimental and Epidemiological Studies Suggest a Role for the Novel Human Polyomaviruses in Cancer

As their name indicates, polyomaviruses (PyVs) can induce tumors. Mouse PyV, hamster PyV and raccoon PyV have been shown to cause tumors in their natural host. During the last 30 years, 15 PyVs have been isolated from humans. From these, Merkel cell PyV is classified as a Group 2A carcinogenic pathogen (probably carcinogenic to humans), whereas BKPyV and JCPyV are class 2B (possibly carcinogenic to humans) by the International Agency for Research on Cancer. Although the other PyVs recently detected in humans (referred to here as novel HPyV; nHPyV) share many common features with PyVs, including the viral oncoproteins large tumor antigen and small tumor antigen, as their role in cancer is questioned. This review discusses whether the nHPyVs may play a role in cancer based on predicted and experimentally proven functions of their early proteins in oncogenic processes. The functional domains that mediate the oncogenic properties of early proteins of known PyVs, that can cause cancer in their natural host or animal models, have been well characterized and we examined whether these functional domains are conserved in the early proteins of the nHPyVs and presented experimental evidence that these conserved domains are functional. Furthermore, we reviewed the literature describing the detection of nHPyV in human tumors.

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.

Trichodysplasia spinulosa polyomavirus small T antigen synergistically modulates S6 protein translation and DNA damage response pathways to shape host cell environment

TSPyV is a viral agent linked to Trichodysplasia spinulosa, a disfiguring human skin disease which presents with hyperkeratotic spicule eruption in immunocompromised hosts. This proliferative disease state requires extensive modulation of the host cell environment. While the small T (sT) antigen of TSPyV has been postulated to cause widespread cellular perturbation, its specific substrates and their mechanistic connection are unclear. To identify the cellular substrates and pathways perturbed by TSPyV sT and propose a nuanced model that reconciles the multiple arms of TSPyV pathogenesis, changes in expression of several proteins and phospho-proteins in TSPyV sT expressing and TSPyV sT deletion mutant-expressing cell lysates were interrogated using Western blot assays. TSPyV sT expression exploits the DNA damage response pathway, by inducing hyperphosphorylation of ATM and 53BP1 and upregulation of BMI-1. Concurrently, sT dysregulates the S6 protein translation pathway via hyperphosphorylation of CDC2, p70 S6 kinase, S6, and PP1α. The S6^S244/247 and p-PP1α^T320 phospho-forms are points of overlap between the DDR and S6 networks. We propose a mechanistic rationale for previous reports positioning sT antigen as the key driver of TSPyV pathogenesis. We illuminate novel targets in the S6 and DDR pathways and recognize a potential synergy between these pathways. TSPyV may sensitize the cell to both unrestricted translation and genomic instability. This multi-pronged infection model may inform future therapeutic modalities against TSPyV and possibly other viruses with overlapping host substrates.

Sustained Trichodysplasia Spinulosa Polyomavirus Viremia Illustrating a Primary Disseminated Infection in a Kidney Transplant Recipient

Novel human polyomaviruses (HPyV) have been recently identified in solid organ transplant recipients. Trichodysplasia spinulosa (TS) is a rare disease associated with immunosuppression and induced by a polyomavirus (TSPyV). We report here a case of primary and disseminated TSPyV infection after kidney transplantation with extensive skin lesions, sustained viremia, and high viral loads in urine specimens, anal, nasal and throat swabs, assessed via specific real-time PCR for TSPyV during a follow-up period of 32 months after transplantation. The detection of TSPyV with a high viral load in respiratory and anal swab samples is compatible with viral replication and thus may suggest potential respiratory and oro-fecal routes of transmission.

Natural History of Cutaneous Human Polyomavirus Infection in Healthy Individuals

Several human polyomaviruses (HPyVs) were recently discovered. Merkel cell polyomavirus (MCPyV) induces Merkel cell carcinoma. HPyV6, HPyV7, and TSPyV have been associated with rare skin lesions in immunosuppressed patients. HPyV9, HPyV10, and Saint Louis Polyomavirus (STLPyV) have not been convincingly associated with any disease. The aim of this prospective study was to evaluate the cutaneous prevalence, persistence and viral load of HPyVs in healthy individuals. Eight hundred seventy forehead and hand swabs were collected from 109 volunteers 4-6 weeks apart (collection period-1). Fifty-nine participants were available for follow-up a decade later (collection period-2). HPyV-DNA prevalence and viral loads of MCPyV, HPyV6, HPyV7, TSPyV, HPyV9, HPyV10, and STLPyV were determined by virus-specific real-time PCRs. Risk factors for HPyV prevalence, short- and long-term persistence were explored by logistic regression analyses. Baseline prevalence rates were similar for forehead and hand: MCPyV 67.9/67.0%, HPyV6 31.2/25.7%, HPyV7 13.8/11.0%, HPyV10 11.9/15.6%, STLPyV 7.3/8.3%, TSPyV 0.9/0.9%, and HPyV9 0.9/0.9%. Short-term persistence in period-1 was found in 59.6% (MCPyV), 23.9% (HPyV6), 10.1% (HPyV7), 6.4% (HPyV10), 5.5% (STLPyV), and 0% (TSPyV and HPyV9) on the forehead, with similar values for the hand. Long-term persistence for 9-12 years occurred only for MCPyV (forehead/hand 39.0%/44.1% of volunteers), HPyV6 (16.9%/11.9%), and HPyV7 (3.4%/5.1%). Individuals with short-term persistence had significantly higher viral loads at baseline compared to those with transient DNA-positivity (p < 0.001 for MCPyV, HPyV6, HPyV7, and HPyV10, respectively). This was also true for median viral loads in period-1 of MCPyV, HPyV6, and HPyV7 of volunteers with long-term persistence. Multiplicity (two or more different HPyVs) was a risk factor for prevalence and persistence for most HPyVs. Further risk factors were older age for HPyV6 and male sex for MCPyV on the forehead. Smoking was not a risk factor. In contrast to MCPyV, HPyV6, HPyV7, and rarely STLPyV, polyomaviruses TSPyV, HPyV9, and HPyV10 do not seem to be long-term constituents of the human skin virome of healthy individuals. Furthermore, this study showed that higher viral loads are associated with both short- and long-term persistence of HPyVs on the skin. HPyV multiplicity is a risk factor for prevalence, short-term and/or long-term persistence of MCPyV, HPyV6, HPyV7, and HPyV10.

Immune sensing of mouse polyomavirus DNA by p204 and cGAS DNA sensors

The mechanism by which DNA viruses interact with different DNA sensors and their connection with the activation of interferon (IFN) type I pathway are poorly understood. We investigated the roles of protein 204 (p204) and cyclic guanosine-adenosine synthetase (cGAS) sensors during infection with mouse polyomavirus (MPyV). The phosphorylation of IFN regulatory factor 3 (IRF3) and the stimulator of IFN genes (STING) proteins and the upregulation of IFN beta (IFN-β) and MX Dynamin Like GTPase 1 (MX-1) genes were detected at the time of replication of MPyV genomes in the nucleus. STING knockout abolished the IFN response. Infection with a mutant virus that exhibits defective nuclear entry via nucleopores and that accumulates in the cytoplasm confirmed that replication of viral genomes in the nucleus is required for IFN induction. The importance of both DNA sensors, p204 and cGAS, in MPyV-induced IFN response was demonstrated by downregulation of the IFN pathway observed in p204-knockdown and cGAS-knockout cells. Confocal microscopy revealed the colocalization of p204 with MPyV genomes in the nucleus. cGAS was found in the cytoplasm, colocalizing with viral DNA leaked from the nucleus and with DNA within micronucleus-like bodies, but also with the MPyV genomes in the nucleus. However, 2'3'-Cyclic guanosine monophosphate-adenosine monophosphate synthesized by cGAS was detected exclusively in the cytoplasm. Biochemical assays revealed no evidence of functional interaction between cGAS and p204 in the nucleus. Our results provide evidence for the complex interactions of MPyV and DNA sensors including the sensing of viral genomes in the nucleus by p204 and of leaked viral DNA and micronucleus-like bodies in the cytoplasm by cGAS.

BK Polyomavirus-Biology, Genomic Variation and Diagnosis

The BK polyomavirus (BKPyV), a representative of the family Polyomaviridae, is widespread in the human population. While the virus does not cause significant clinical symptoms in immunocompetent individuals, it is activated in cases of immune deficiency, both pharmacological and pathological. Infection with the BKPyV is of particular importance in recipients of kidney transplants or HSC transplantation, in which it can lead to the loss of the transplanted kidney or to haemorrhagic cystitis, respectively. Four main genotypes of the virus are distinguished on the basis of molecular differentiation. The most common genotype worldwide is genotype I, with a frequency of about 80%, followed by genotype IV (about 15%), while genotypes II and III are isolated only sporadically. The distribution of the molecular variants of the virus is associated with the region of origin. BKPyV subtype Ia is most common in Africa, Ib-1 in Southeast Asia, and Ib-2 in Europe, while Ic is the most common variant in Northeast Asia. The development of molecular methods has enabled significant improvement not only in BKPyV diagnostics, but in monitoring the effectiveness of treatment as well. Amplification of viral DNA from urine by PCR (Polymerase Chain Reaction) and qPCR Quantitative Polymerase Chain Reaction) is a non-invasive method that can be used to confirm the presence of the genetic material of the virus and to determine the viral load. Sequencing techniques together with bioinformatics tools and databases can be used to determine variants of the virus, analyse their circulation in populations, identify relationships between them, and investigate the directions of evolution of the virus.

Detection of Quebec Polyomavirus DNA in Samples from Different Patient Groups

Polyomaviruses infect many species, including humans. So far, 15 polyomaviruses have been described in humans, but it remains to be established whether all of these are genuine human polyomaviruses. The most recent polyomavirus to be detected in a person is Quebec polyomavirus (QPyV), which was identified in a metagenomic analysis of a stool sample from an 85-year-old hospitalized man. We used PCR to investigate the presence of QPyV DNA in urine samples from systemic lupus erythematosus (SLE) patients (67 patients; 135 samples), multiple sclerosis patients (n = 35), HIV-positive patients (n = 66) and pregnant women (n = 65). Moreover, cerebrospinal fluid from patients with suspected neurological diseases (n = 63), nasopharyngeal aspirates from patients (n = 80) with respiratory symptoms and plasma samples from HIV-positive patients (n = 65) were examined. QPyV DNA was found in urine from 11 (16.4%), 10 (15.4%) and 5 (14.3%) SLE patients, pregnant women, and multiple sclerosis patients, respectively. No QPyV DNA could be detected in the other samples. Alignment with the only available QPyV sequence in the GenBank revealed amino acid substitutions in the HI-loop of capsid protein VP1 in 6/28 of the isolates. Our results show that QPyV viruria can occur, but whether it may cause clinical symptoms in the patients remains to be determined.

Characterization of ALTO-encoding circular RNAs expressed by Merkel cell polyomavirus and trichodysplasia spinulosa polyomavirus

Circular RNAs (circRNAs) are a conserved class of RNAs with diverse functions, including serving as messenger RNAs that are translated into peptides. Here we describe circular RNAs generated by human polyomaviruses (HPyVs), some of which encode variants of the previously described alternative large T antigen open reading frame (ALTO) protein. Circular ALTO RNAs (circALTOs) can be detected in virus positive Merkel cell carcinoma (VP-MCC) cell lines and tumor samples. CircALTOs are stable, predominantly located in the cytoplasm, and N6-methyladenosine (m6A) modified. The translation of MCPyV circALTOs into ALTO protein is negatively regulated by MCPyV-generated miRNAs in cultured cells. MCPyV ALTO expression increases transcription from some recombinant promoters in vitro and upregulates the expression of multiple genes previously implicated in MCPyV pathogenesis. MCPyV circALTOs are enriched in exosomes derived from VP-MCC lines and circALTO-transfected 293T cells, and purified exosomes can mediate ALTO expression and transcriptional activation in MCPyV-negative cells. The related trichodysplasia spinulosa polyomavirus (TSPyV) also expresses a circALTO that can be detected in infected tissues and produces ALTO protein in cultured cells. Thus, human polyomavirus circRNAs are expressed in human tumors and infected tissues and express proteins that have the potential to modulate the infectious and tumorigenic properties of these viruses.

The contribution of human papilloma virus infection to cutaneous squamous cell carcinoma in patients with chronic lymphocytic leukemia

Patients with chronic lymphocytic leukemia (CLL), a B‐cell malignancy characterized by impaired humoral and cellular immunity, are at increased risk of developing cutaneous squamous cell carcinoma (cSCC). Human papilloma virus (HPV) is the most common sexually transmitted infection worldwide and it has been associated with various malignancies, including cSCC. Impaired cell‐mediated immunity is considered a primary risk factor in HPV‐induced cSCC. We examined cSCC lesions from CLL patients with consensus review and HPV genetic analysis to further characterize the relationship between HPV and prevalence of cutaneous malignancy in this population. Eleven patients with CLL contributed 35 cSCCs. Treatment with chemotherapy shortened the latency time to first cSCC. HPV was detected in 54% of the lesions. Among the HPV‐positive cSCC lesions, 84% of the lesions contained alpha‐genus HPV, 42% contained beta‐genus HPV, and 26% of the lesions contained both genera. There was a significant association between HPV‐containing lesions and peritumoral lymphocytic inflammation, suggesting this as a future area for further characterization. The majority of the lesions, including those with alpha‐genus HPV, occurred in sun‐exposed areas, such as the scalp and face. These findings may lead to practice‐changing recommendations for skin cancer, including the use of vaccinations to reduce HPV‐associated skin cancer.

Biology of Polyomavirus miRNA

Polyomaviruses are a family of non-enveloped DNA viruses with wide host ranges. Human polyomaviruses typically cause asymptomatic infection and establish persistence but can be reactivated under certain conditions and cause severe diseases. Most well studied polyomaviruses encode a viral miRNA that regulates viral replication and pathogenesis by targeting both viral early genes and host genes. In this review, we summarize the current knowledge of polyomavirus miRNAs involved in virus infection. We review in detail the regulation of polyomavirus miRNA expression, as well as the role polyomavirus miRNAs play in viral pathogenesis by controlling both host and viral gene expression. An overview of the potential application of polyomavirus miRNA as a marker for the progression of polyomaviruses associated diseases and polyomaviruses reactivation is also included.

Antivirals against human polyomaviruses: Leaving no stone unturned

Human polyomaviruses (HPyVs) encompass more than 10 species infecting 30%-90% of the human population without significant illness. Proven HPyV diseases with documented histopathology affect primarily immunocompromised hosts with manifestations in brain, skin and renourinary tract such as polyomavirus-associated nephropathy (PyVAN), polyomavirus-associated haemorrhagic cystitis (PyVHC), polyomavirus-associated urothelial cancer (PyVUC), progressive multifocal leukoencephalopathy (PML), Merkel cell carcinoma (MCC), Trichodysplasia spinulosa (TS) and pruritic hyperproliferative keratinopathy. Although virus-specific immune control is the eventual goal of therapy and lasting cure, antiviral treatments are urgently needed in order to reduce or prevent HPyV diseases and thereby bridging the time needed to establish virus-specific immunity. However, the small dsDNA genome of only 5 kb of the non-enveloped HPyVs only encodes 5-7 viral proteins. Thus, HPyV replication relies heavily on host cell factors, thereby limiting both, number and type of specific virus-encoded antiviral targets. Lack of cost-effective high-throughput screening systems and relevant small animal models complicates the preclinical development. Current clinical studies are limited by small case numbers, poorly efficacious compounds and absence of proper randomized trial design. Here, we review preclinical and clinical studies that evaluated small molecules with presumed antiviral activity against HPyVs and provide an outlook regarding potential new antiviral strategies.

Sending mixed signals: polyomavirus entry and trafficking

Polyomaviruses are mostly non-pathogenic, yet some can cause human disease especially under conditions of immunosuppression, including JC, BK, and Merkel cell polyomaviruses. Direct interactions between viruses and the host early during infection dictate the outcome of disease, many of which remain enigmatic. However, significant work in recent years has contributed to our understanding of how this virus family establishes an infection, largely due to advances made for animal polyomaviruses murine and SV40. Here we summarize the major findings that have contributed to our understanding of polyomavirus entry, trafficking, disassembly, signaling, and immune evasion during the infectious process and highlight major unknowns in these processes that are open areas of study.

Preliminary assessment of viral metagenome from cancer tissue and blood from patients with lung adenocarcinoma

In this study, using a viral metagenomic method, we investigated the composition of virome in blood and cancer tissue samples that were collected from 25 patients with lung adenocarcinoma. Results indicated that virus sequences showing similarity to human pegivirus (HPgV), anellovirus, human endogenous retrovirus (HERV), and polyomavirus were recovered from this cohort. Three different complete genomes of HPgV were acquired from the blood samples and one complete genome of polyomavirus was determined from the cancer tissue sample. Phylogenetic analysis indicated that the three HPgV strains belonged to genotype 3 and the polyomavirus showed the highest sequence identity (99.73%) to trichodysplasia spinulosa-associated polyomavirus. PCR screening results indicated that the three HPgVs were present in 5 out of the 25 blood samples and the polyomavirus only existed in a cancer tissue sample pool. Whether infections with viruses have an association with lung cancer needs further study with a larger size of sampling.

Identification of Polyomaviruses in Skin Cancers

BACKGROUND

Polyomaviruses (PyVs) were initially described in animals. They have also been detected in humans with some evidence that could play a role in skin carcinogenesis.

OBJECTIVES

This study aimed to verify the presence of PyVs in different skin tumour samples and to make clinical correlations with patients' epidemiological data from Clinics Hospital of Medical School of University of São Paulo, Brazil.

METHODS

This is a cross-sectional study. A random selection was performed of 120 patients with histopathological exams of different cutaneous neoplasms equally divided into 6 groups and 20 patients with normal skin. The available skin specimens were analysed with 2 different techniques of PCR (conventional and real time) for detection of PyV DNA. Concomitantly, retrospective analysis of the respective medical records for the collection of epidemiological data was done. Analyses suitable for categorical data were used to compare the proportion of patients in each group.

RESULTS

PyV DNA was found in 25.69% of the samples: 15% in basal cell carcinoma group, 15% in squamous cell carcinoma, 28.57% in melanoma, 15% in dermatofibrosarcoma protuberans, 13.33% in Kaposi sarcoma, 65% in Merkel cell carcinoma (MCC), and none in normal skin. Merkel cell PyV detection was statistically significant in MCC patients (p value <0.01), but no correlations were found between PyVs and others skin tumours.

CONCLUSION

This study demonstrated the presence of PyVs in different skin tumours; however, no association of any PyVs found in any skin tumour with epidemiological data could be shown. Further studies are still needed to elucidate the mechanisms of PyVs in skin carcinogenesis.

HPyV6 and HPyV7 in urine from immunocompromised patients

Background

Human polyomavirus 6 (HPyV6) and HPyV7 are two of the novel polyomaviruses that were originally detected in non-diseased skin. Serological studies have shown that these viruses are ubiquitous in the healthy adult population with seroprevalence up to 88% for HPyV6 and 72% for HPyV7. Both viruses are associated with pruritic skin eruption in immunocompromised patients, but a role with other diseases in immunoincompetent patients or malignancies has not been established.

Methods

PCR was used to determine the presence of HPyV6 and HPyV7 DNA in urine samples from systemic lupus erythematosus (n = 73), multiple sclerosis (n = 50), psoriasis vulgaris (n = 15), arthritic psoriasis (n = 15) and HIV-positive patients (n = 66). In addition, urine from pregnant women (n = 47) and healthy blood donors (n = 20) was investigated.

Results

HPyV6 DNA was detected in 21 (28.8%) of the urine specimens from SLE patients, in 6 (9.1%) of the urine samples from the HIV-positive cohort, and in 19 (40.4%) samples from pregnant women. HPyV7 DNA was only found in 6 (8.2%) of the urine specimens from SLE patients and in 4 (8.5%) samples from pregnant women. No HPyV6 and HPyV7 viruria was detected in the urine samples from the other patients.

Conclusions

HPyV6, and to a lesser extend HPyV7, viruria seems to be common in SLE and HIV-positive patients, and pregnant women. Whether these viruses are of clinical relevance in these patients is not known.

Trichodysplasia spinulosa: a comprehensive review of the disease and its treatment

Trichodysplasia spinulosa (TS) is a rare dermatological disease caused by TS‐associated polyomavirus (TSPyV) in immunosuppressed patients. The seroprevalence of TSPyV in immunocompetent adults is high and the number of immunosuppressed patients developing TS remains low, suggesting that TS is underdiagnosed and/or that additional unknown factors are needed in order to develop TS. There is no well‐established treatment for TS, and to date a majority of reported cases have consequently received ineffective therapies, likely due to the unavailability of reviews and recommendations of treatments for TS. The few treatments reported in case reports to be effective include topical cidofovir 3%, reduction of immunosuppression and oral valganciclovir. In this comprehensive review, we present all published cases to date, together with a summary of all treatments for TS categorized by overall clinical efficacy, thus addressing this rare disease and what appears to be its clinically efficacious treatment.

Genetic Diversity of the Noncoding Control Region of the Novel Human Polyomaviruses

The genomes of polyomaviruses are characterized by their tripartite organization with an early region, a late region and a noncoding control region (NCCR). The early region encodes proteins involved in replication and transcription of the viral genome, while expression of the late region generates the capsid proteins. Transcription regulatory sequences for expression of the early and late genes, as well as the origin of replication are encompassed in the NCCR. Cell tropism of polyomaviruses not only depends on the appropriate receptors on the host cell, but cell-specific expression of the viral genes is also governed by the NCCR. Thus far, 15 polyomaviruses have been isolated from humans, though it remains to be established whether all of them are genuine human polyomaviruses (HPyVs). The sequences of the NCCR of these HPyVs show high genetic variability and have been best studied in the human polyomaviruses BK and JC. Rearranged NCCRs in BKPyV and JCPyV, the first HPyVs to be discovered approximately 30 years ago, have been associated with the pathogenic properties of these viruses in nephropathy and progressive multifocal leukoencephalopathy, respectively. Since 2007, thirteen novel PyVs have been isolated from humans: KIPyV, WUPyV, MCPyV, HPyV6, HPyV7, TSPyV, HPyV9, HPyV10, STLPyV, HPyV12, NJPyV, LIPyV and QPyV. This review describes all NCCR variants of the new HPyVs that have been reported in the literature and discusses the possible consequences of NCCR diversity in terms of promoter strength, putative transcription factor binding sites and possible association with diseases.

Molecular Pathogenesis of Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine carcinoma of the skin with two distinct etiologies. Clonal integration of Merkel cell polyomavirus DNA into the tumor genome with persistent expression of viral T antigens causes at least 60% of all MCC. UV damage leading to highly mutated genomes causes a nonviral form of MCC. Despite these distinct etiologies, both forms of MCC are similar in presentation, prognosis, and response to therapy. At least three oncogenic transcriptional programs feature prominently in both forms of MCC driven by the virus or by mutation. Both forms of MCC have a high proliferative growth rate with increased levels of cell cycle-dependent genes due to inactivation of the tumor suppressors RB and p53, a strong MYC signature due to MYCL activation by the virus or gene amplification, and an attenuated neuroendocrine differentiation program driven by the ATOH1 transcription factor.

A Comprehensive Proteomics Analysis of the JC Virus (JCV) Large and Small Tumor Antigen Interacting Proteins: Large T Primarily Targets the Host Protein Complexes with V-ATPase and Ubiquitin Ligase Activities While Small t Mostly Associates with Those Having Phosphatase and Chromatin-Remodeling Functions

The oncogenic potential of both the polyomavirus large (LT-Ag) and small (Sm t-Ag) tumor antigens has been previously demonstrated in both tissue culture and animal models. Even the contribution of the MCPyV tumor antigens to the development of an aggressive human skin cancer, Merkel cell carcinoma, has been recently established. To date, the known primary targets of these tumor antigens include several tumor suppressors such as pRb, p53, and PP2A. However, a comprehensive list of the host proteins targeted by these proteins remains largely unknown. Here, we report the first interactome of JCV LT-Ag and Sm t-Ag by employing two independent “affinity purification/mass spectroscopy” (AP/MS) assays. The proteomics data identified novel targets for both tumor antigens while confirming some of the previously reported interactions. LT-Ag was found to primarily target the protein complexes with ATPase (v-ATPase and Smc5/6 complex), phosphatase (PP4 and PP1), and ligase (E3-ubiquitin) activities. In contrast, the major targets of Sm t-Ag were identified as Smarca1/6, AIFM1, SdhA/B, PP2A, and p53. The interactions between “LT-Ag and SdhB”, “Sm t-Ag and Smarca5”, and “Sm t-Ag and SDH” were further validated by biochemical assays. Interestingly, perturbations in some of the LT-Ag and Sm t-Ag targets identified in this study were previously shown to be associated with oncogenesis, suggesting new roles for both tumor antigens in novel oncogenic pathways. This comprehensive data establishes new foundations to further unravel the new roles for JCV tumor antigens in oncogenesis and the viral life cycle.

Taking the Scenic Route: Polyomaviruses Utilize Multiple Pathways to Reach the Same Destination

Members of the Polyomaviridae family differ in their host range, pathogenesis, and disease severity. To date, some of the most studied polyomaviruses include human JC, BK, and Merkel cell polyomavirus and non-human subspecies murine and simian virus 40 (SV40) polyomavirus. Although dichotomies in host range and pathogenesis exist, overlapping features of the infectious cycle illuminate the similarities within this virus family. Of particular interest to human health, JC, BK, and Merkel cell polyomavirus have all been linked to critical, often fatal, illnesses, emphasizing the importance of understanding the underlying viral infections that result in the onset of these diseases. As there are significant overlaps in the capacity of polyomaviruses to cause disease in their respective hosts, recent advancements in characterizing the infectious life cycle of non-human murine and SV40 polyomaviruses are key to understanding diseases caused by their human counterparts. This review focuses on the molecular mechanisms by which different polyomaviruses hijack cellular processes to attach to host cells, internalize, traffic within the cytoplasm, and disassemble within the endoplasmic reticulum (ER), prior to delivery to the nucleus for viral replication. Unraveling the fundamental processes that facilitate polyomavirus infection provides deeper insight into the conserved mechanisms of the infectious process shared within this virus family, while also highlighting critical unique viral features.

Prevalence and viral loads of polyomaviruses BKPyV, JCPyV, MCPyV, TSPyV and NJPyV and hepatitis viruses HBV, HCV and HEV in HIV-infected patients in China

Human polyomaviruses (PyVs) and hepatitis viruses are often more prevalent or persistent in human immunodeficiency virus (HIV)-infected persons and the associated diseases are more abundant than in immunocompetent individuals. Here, we evaluated seroreactivities and viral loads of human PyVs and hepatitis viruses in HIV/AIDS patients and the general population in China in the combination antiretroviral therapy (cART) era. A total of 810 HIV-1-infected patients and age- and sex-matched HIV-negative individuals were enrolled to assess seroprevalence of PyVs BKPyV, JCPyV, MCPyV, TSPyV, and NJPyV and hepatitis viruses HBV, HCV, and HEV. 583 (72%) patients received cART, and among them, 31.2% had undetectable HIV RNA. While no significant difference was observed in prevalence of anti-PyV antibodies between HIV-positive and -negative groups, serum DNA positivity and DNA copy level of MCPyV were higher in the HIV-positive group. Among HIV-infected patients, BKPyV DNA positivity was significantly higher in patients with CD4 + cell counts < 200 cells/mm³ compared to those with CD4 + cell counts > 500 cells/mm³, suggesting possible reactivation caused by HIV-induced immune suppression. Higher HBV and HCV seropositivities but not HEV seropositivity were also observed in the HIV-positive group. Further correlation analyses demonstrated that HBV and HEV are potential risk factors for increased prevalence of PyV infection.

Human Polyomavirus 6 Detected in Cases of Eosinophilic Pustular Folliculitis

BACKGROUND

Human polyomaviruses (HPyVs) have been associated with several cutaneous inflammatory conditions. More investigation is needed to identify further presentations of cutaneous pathology associated with HPyVs. Our aim was to investigate the possible association of skin-tropic HPyVs with folliculitis, particularly eosinophilic pustular folliculitis (EPF).

METHODS

This study included 55 Japanese patients, comprising 13 patients with EPF and 42 patients with suppurative folliculitis. HPyV DNAs were detected by quantitative polymerase chain reaction. Expression of viral antigen and geographically related viral genotypes were also assessed.

RESULTS

Human polyomavirus 6 (HPyV6) DNA was found in 9 of 13 (69%) patients with EPF, a rate significantly higher than that found in suppurative folliculitis (1/42; 2%). Of the 7 HPyV6 DNA-positive EPF specimens analyzed, 4 were positive for HPyV6 small tumor antigen. All the HPyV6 strains detected in this study were of the Asian/Japanese genotype.

CONCLUSIONS

The predominant detection of HPyV6 DNA and the expression of viral antigen suggest a possible association between HPyV6 infection and EPF in a subset of patients. Worldwide studies are warranted to determine whether Asian/Japanese genotype HPyV6 is associated preferentially with the incidence and pathogenesis of this eosinophil-related skin disease that has an ethnic predilection for the East Asian population.

Trichodysplasia spinulosa in a renal transplant patient: A case report of successful treatment

Trichodysplasia spinulosa is a rare cutaneous disease caused by the trichodysplasia spinulosa–associated polyomavirus. It occurs more frequently in immunocompromised patients, particularly in solid organ transplants. A few successful treatments have been described in the literature. In our report, we present a biopsy-proven trichodysplasia spinulosa case in a kidney transplant recipient who rapidly responded to a reduction of his immunosuppressive therapy.

Fifty Years of JC Polyomavirus: A Brief Overview and Remaining Questions

In the fifty years since the discovery of JC polyomavirus (JCPyV), the body of research representing our collective knowledge on this virus has grown substantially. As the causative agent of progressive multifocal leukoencephalopathy (PML), an often fatal central nervous system disease, JCPyV remains enigmatic in its ability to live a dual lifestyle. In most individuals, JCPyV reproduces benignly in renal tissues, but in a subset of immunocompromised individuals, JCPyV undergoes rearrangement and begins lytic infection of the central nervous system, subsequently becoming highly debilitating-and in many cases, deadly. Understanding the mechanisms allowing this process to occur is vital to the development of new and more effective diagnosis and treatment options for those at risk of developing PML. Here, we discuss the current state of affairs with regards to JCPyV and PML; first summarizing the history of PML as a disease and then discussing current treatment options and the viral biology of JCPyV as we understand it. We highlight the foundational research published in recent years on PML and JCPyV and attempt to outline which next steps are most necessary to reduce the disease burden of PML in populations at risk.

Beyond Cytomegalovirus and Epstein-Barr Virus: a Review of Viruses Composing the Blood Virome of Solid Organ Transplant and Hematopoietic Stem Cell Transplant Recipients

Viral primary infections and reactivations are common complications in patients after solid organ transplantation (SOT) and hematopoietic stem cell transplantation (HSCT) and are associated with high morbidity and mortality. Among these patients, viral infections are frequently associated with viremia. Beyond the usual well-known viruses that are part of the routine clinical management of transplant recipients, numerous other viral signatures or genomes can be identified in the blood of these patients. The identification of novel viral species and variants by metagenomic next-generation sequencing has opened up a new field of investigation and new paradigms. Thus, there is a need to thoroughly describe the state of knowledge in this field with a review of all viral infections that should be scrutinized in high-risk populations. Here, we review the eukaryotic DNA and RNA viruses identified in blood, plasma, or serum samples of pediatric and adult SOT/HSCT recipients and the prevalence of their detection, with a particular focus on recently identified viruses and those for which their potential association with disease remains to be investigated, such as members of the Polyomaviridae, Anelloviridae, Flaviviridae, and Astroviridae families. Current knowledge of the clinical significance of these viral infections with associated viremia among transplant recipients is also discussed. To ensure a comprehensive description in these two populations, individuals described as healthy (mostly blood donors) are considered for comparative purposes. The list of viruses that should be on the clinicians' radar is certainly incomplete and will expand, but the challenge is to identify those of possible clinical significance.