WU and KI polyomaviruses in respiratory samples from allogeneic hematopoietic cell transplant recipients

Polyomaviruses After Allogeneic Hematopoietic Stem Cell Transplantation

Polyomaviruses (PyVs) are non-enveloped double-stranded DNA viruses that can cause significant morbidity in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients, particularly BK polyomavirus (BKPyV) and JC polyomavirus (JCPyV). BKPyV is primarily associated with hemorrhagic cystitis (HC), while JCPyV causes progressive multifocal leukoencephalopathy (PML). The pathogenesis of these diseases involves viral reactivation under immunosuppressive conditions, leading to replication in tissues such as the kidney, bladder, and central nervous system. BKPyV-HC presents as hematuria and urinary symptoms, graded by severity. PML, though rare after allo-HSCT, manifests as neurological deficits due to JCPyV replication in glial cells. Diagnosis relies on nucleic acid amplification testing for DNAuria or DNAemia as well as clinical criteria. Management primarily involves supportive care, as no antiviral treatments have proven consistently effective for either virus and need further research. This review highlights the virology, clinical presentations, and management challenges of PyV-associated diseases post-allo-HSCT, emphasizing the need for improved diagnostic tools and therapeutic approaches to mitigate morbidity and mortality in this vulnerable population.

KI and WU Polyomaviruses: Seroprevalence Study and DNA Prevalence in SARS-CoV-2 RNA Positive and Negative Respiratory Samples

The aim of this work was to study the possible co-infection of KI and WU polyomavirus (KIPyV and WUPyV, respectively) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in respiratory samples and to detect the seroprevalence of KIPyV and WUPyV. A total of 1030 nasopharyngeal samples were analyzed from SARS-CoV-2 RNA positive (n = 680) and negative (n = 350) adults and children (age: 1 day to 94.2 years) collected from August 2020 to October 2021. KIPyV DNA was detected in two SARS-CoV-2-positive samples (2/680, 0.29%) and in three SARS-CoV-2-negative samples (3/350, 0.86%). WUPyV DNA was observed in one-one samples from both groups (1/680, 0.15% vs. 1/350, 0.29%). We did not find an association between SARS-CoV-2 and KIPyV or WUPyV infection, and we found low DNA prevalence of polyomaviruses studied after a long-term lockdown in Hungary. To exclude a geographically different distribution of these polyomaviruses, we studied the seroprevalence of KIPyV and WUPyV by enzyme-linked immunosorbent assay among children and adults (n = 692 for KIPyV and n = 705 for WUPyV). Our data confirmed that primary infections by KIPyV and WUPyV occur mainly during childhood; the overall seropositivity of adults was 93.7% and 89.2% for KIPyV and WUPyV, respectively. Based on our data, we suggest that the spread of KIPyV and WUPyV might have been restricted in Hungary by the lockdown.

KI and WU Polyomavirus in Respiratory Samples of SARS-CoV-2 Infected Patients

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has been declared a global pandemic. Our goal was to determine whether co-infections with respiratory polyomaviruses, such as Karolinska Institutet polyomavirus (KIPyV) and Washington University polyomavirus (WUPyV) occur in SARS-CoV-2 infected patients. Oropharyngeal swabs from 150 individuals, 112 symptomatic COVID-19 patients and 38 healthcare workers not infected by SARS-CoV-2, were collected from March 2020 through May 2020 and tested for KIPyV and WUPyV DNA presence. Of the 112 SARS-CoV-2 positive patients, 27 (24.1%) were co-infected with KIPyV, 5 (4.5%) were positive for WUPyV, and 3 (2.7%) were infected simultaneously by KIPyV and WUPyV. Neither KIPyV nor WUPyV DNA was detected in samples of healthcare workers. Significant correlations were found in patients co-infected with SARS-CoV-2 and KIPyV (p < 0.05) and between SARS-CoV-2 cycle threshold values and KIPyV, WUPyV and KIPyV and WUPyV concurrently detected (p < 0.05). These results suggest that KIPyV and WUPyV may behave as opportunistic respiratory pathogens. Additional investigations are needed to understand the epidemiology and the prevalence of respiratory polyomavirus in COVID-19 patients and whether KIPyV and WUPyV could potentially drive viral interference or influence disease outcomes by upregulating SARS-CoV-2 replicative potential.

Heterogeneous associations of polyomaviruses and herpesviruses with allergy-related phenotypes in childhood

BACKGROUND

Evidence suggests a complex interplay between infections and allergic diseases.

OBJECTIVE

To explore the association of 14 common viruses with eczema, asthma, and rhinoconjunctivitis in childhood.

METHODS

We used cross-sectional (n = 686) and prospective (n = 440) data from children participating in the Rhea birth cohort. Immunoglobulin G to polyomaviruses (BK polyomavirus, JC polyomavirus, KI polyomavirus [KIPyV], WU polyomavirus [WUPyV], human polyomavirus 6, human polyomavirus 7, Trichodysplasia spinulosa polyomavirus, Merkel cell polyomavirus, human polyomavirus 9, and human polyomavirus 10) and herpesviruses (Epstein-Barr virus, Cytomegalovirus, Herpes simplex virus-1, Herpes simplex virus-2) were measured at age 4 years by fluorescent bead-based multiplex serology. Definitions of eczema, asthma, and rhinoconjunctivitis at ages 4 and 6 years were based on questionnaires. Mediation of the associations by immune biomarkers was tested.

RESULTS

Less likely to have eczema at age 4 years were KIPyV-seropositive (odds ratio [OR], 0.47; 95% confidence interval [CI], 0.27-0.82) and human polyomavirus 6 (OR, 0.44; 95% CI, 0.26-0.73) compared with their seronegative counterparts. Seropositivity to Epstein-Barr virus was negatively associated with eczema at age 4 years (OR, 0.39; 95% CI, 0.22-0.67) and 6 years (OR, 0.50; 95% CI, 0.25-0.99). Children with a higher burden of herpesviruses or of skin polyomaviruses had the lowest odds of eczema at age 4 years. Higher odds for asthma at age 4 years were found for WUPyV-seropositive children (OR, 3.98; 95% CI, 1.38-11.51), and for children seropositive to both respiratory polyomaviruses (KIPyV and WUPyV) (OR, 7.35; 95% CI, 1.66-32.59) compared with children seronegative to both. No associations were observed for rhinoconjunctivitis. There was no evidence of mediation by immune biomarkers.

CONCLUSION

A heterogeneous pattern of infections and allergic diseases was observed with common infections associated with a decreased eczema risk and an increased asthma risk in children.

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.

Role of Human Bocavirus Respiratory Tract Infection in Hematopoietic Cell Transplant Recipients

BACKGROUND

Limited data exist regarding the impact of human bocavirus (BoV) in hematopoietic cell transplant (HCT) recipients.

METHODS

In a longitudinal surveillance study among allogeneic HCT recipients, pre-HCT and weekly post-HCT nasal washes and symptom surveys were collected through day 100, then at least every 3 months through 1 year post-HCT at the Fred Hutch (2005-2010). Samples were tested by multiplex semi-quantitative PCR for 12 viruses. Plasma samples from BoV+ subjects were analyzed by PCR. Separately, we conducted a retrospective review of HCT recipients with BoV detected in lower respiratory tract specimens.

RESULTS

Among 51 children and 420 adults in the prospective cohort, 21 distinct BoV respiratory tract infections (RTIs) were observed by 1 year post-HCT in 19 patients. Younger age and exposure to children were risk factors for BoV acquisition. Univariable models among patients with BoV RTI showed higher peak viral load in nasal samples (p=0.04) and presence of respiratory copathogens (p=0.03) were associated with presence of respiratory symptoms but BoV plasma detection was not. Only watery eyes and rhinorrhea were associated with BoV RTI in adjusted models. With additional chart review, we identified 6 HCT recipients with BoV detected in lower respiratory tract specimens [incidence rate of 0.4% (9/2509) per sample tested]. Although all cases presented with hypoxemia, 4 had respiratory copathogens or concomitant conditions that contributed to respiratory compromise.

CONCLUSIONS

BoV RTI is infrequent in transplant recipients and associated with mild symptoms. Our studies did not demonstrate convincing evidence that BoV is a serious respiratory pathogen.

Survey of WU and KI polyomaviruses, coronaviruses, respiratory syncytial virus and parechovirus in children under 5 years of age in Tehran, Iran

BACKGROUND AND OBJECTIVES

Severe acute respiratory infections (SARI) remain an important cause for childhood morbidity worldwide. We designed a research with the objective of finding the frequency of respiratory viruses, particularly WU and KI polyomaviruses (WUPyV & KIPyV), human coronaviruses (HCoVs), human respiratory syncytial virus (HRSV) and human parechovirus (HPeV) in hospitalized children who were influenza negative.

MATERIALS AND METHODS

Throat swabs were collected from children younger than 5 years who have been hospitalized for SARI and screened for WUPyV, KIPyV, HCoVs, HRSV and HPeV using Real time PCR.

RESULTS

A viral pathogen was identified in 23 (11.16%) of 206 hospitalized children with SARI. The rate of virus detection was considerably greater in infants <12 months (78.2%) than in older children (21.8%). The most frequently detected viruses were HCoVs with 7.76% of positive cases followed by KIPyV (2%) and WUPyV (1.5%). No HPeV and HRSV were detected in this study.

CONCLUSION

This research shown respiratory viruses as causes of childhood acute respiratory infections, while as most of mentioned viruses usually causes mild respiratory diseases, their frequency might be higher in outpatient children. Meanwhile as HRSV is really sensitive to inactivation due to environmental situations and its genome maybe degraded, then for future studies, we need to use fresh samples for HRSV detection. These findings addressed a need for more studies on viral respiratory tract infections to help public health.

Impacts and Challenges of Advanced Diagnostic Assays for Transplant Infectious Diseases

The advanced technologies described in this chapter should allow for full inventories to be made of bacterial genes, their time- and place-dependent expression, and the resulting proteins as well as their outcome metabolites. The evolution of these molecular technologies will continue, not only in the microbial pathogens but also in the context of host-pathogen interactions targeting human genomics and transcriptomics. Their performance characteristics and limitations must be clearly understood by both laboratory personnel and clinicians to ensure proper utilization and interpretation.

Study of Karolinska Institutet and Washington University polyomaviruses in tonsil, adenoid, throat swab and middle ear fluid samples

AIM

To study prevalence of Karolinska Institutet (KI) and Washington University (WU) polyomavirus (PyV) in 100 tonsils, 100 adenoids, 146 throat swab and 15 middle ear fluid samples collected from 146 patients (120 children and 26 adults), to analyze the sequence of  noncoding control region (NCCR) and complete WUPyV genomes.

MATERIALS & METHODS

Viruses were detected by quantitative real-time PCR. The NCCRs and WUPyV genomes were sequenced and analyzed.

RESULTS

The frequency of WUPyV and KIPyV DNA was 27 and 11% in adenoids, 4 and 3% in tonsils, 4.1 and 1.4% in throat swab samples, respectively. The WUPyV DNA was detected in one middle ear fluid sample as well. The WUPyV NCCRs showed mutations which may alter the putative transcription factor binding sites. Phylogenetic analysis revealed three clades of WUPyV.

CONCLUSION

Tonsils and adenoids might be site of virus replication and/or persistence, and WUPyV may invade into the middle ear.

Hospital-based Influenza Morbidity and Mortality (HIMM) Surveillance for A/H7N9 Influenza Virus Infection in Returning Travelers

Since 2013, the Hospital-based Influenza Morbidity and Mortality (HIMM) surveillance system began a H7N9 influenza surveillance scheme for returning travelers in addition to pre-existing emergency room (ER)-based influenza-like illness (ILI) surveillance and severe acute respiratory infection (SARI) surveillance. Although limited to eastern China, avian A/H7N9 influenza virus is considered to have the highest pandemic potential among currently circulating influenza viruses. During the study period between October 1st, 2013 and April 30th, 2016, 11 cases presented with ILI within seven days of travel return. These patients visited China, Hong Kong, or neighboring Southeast Asian countries, but none of them visited a livestock market. Seasonal influenza virus (54.5%, 6 among 11) was the most common cause of ILI among returning travelers, and avian A/H7N9 influenza virus was not detected during the study period.

Survey of KI, WU, MW, and STL Polyomavirus in Cancerous and Non-Cancerous Lung Tissues

BACKGROUND/AIMS

The pathogenesis of the human polyomavirus (PyV) KI, WU, MW, and STL has not been elucidated yet. Respiratory transmission is suggested, but the site of the replication, tissue, and cell tropism is not clarified. KIPyV and WUPyV DNA and/or antigen were detected in normal lung tissues previously by others. In fact, a KIPyV DNA sequence was found in lung cancer samples. Up to date, there is no publication about the DNA prevalence of MWPyV and STLPyV neither in normal nor in cancerous lung tissues. The aim of the present study was to examine the DNA prevalence of these polyomaviruses in cancerous and non-cancerous lung tissue samples, in order to study the possible site for viral replication and/or persistence, and the potential association of these viruses with lung carcinogenesis as well.

METHODS

100 cancerous and 47 non-cancerous, formalin-fixed paraffin-embedded lung tissue samples were studied for KIPyV, WUPyV, MWPyV, and STLPyV by real-time PCR.

RESULTS AND CONCLUSION

Neither of the viruses was found in samples from small-cell, non-small-cell (adenocarcinoma, squamous-cell carcinoma and large-cell neuroendocrine lung cancer), mixed-type and non-differentiated lung carcinoma, and non-cancerous lung tissues (from patients with pneumonia, emphysema and fibrosis).

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.

Year-round influenza immunisation during pregnancy in Nepal: a phase 4, randomised, placebo-controlled trial

BACKGROUND

Influenza immunisation during pregnancy is recommended but not widely implemented in some low-income regions. We assessed the safety and efficacy in mothers and infants of year-round maternal influenza immunisation in Nepal, where influenza viruses circulate throughout the year.

METHODS

In this phase 4, randomised, placebo-controlled trial, we enrolled two consecutive sequential annual cohorts of pregnant women from the Sarlahi district in southern Nepal. We randomised mothers 1:1 to receive seasonally recommended trivalent inactivated influenza vaccine or saline placebo in blocks of eight, stratified by gestational age at enrolment (17-25 weeks vs 26-34 weeks). Women were eligible if they were married, 15-40 years of age, 17-34 weeks' gestation at enrolment, and had not previously received any influenza vaccine that season. We collected serum samples before and after immunisation, and cord blood from a subset of women and infants. Staff masked to allocation made home visits every week from enrolment to 6 months after delivery. Midnasal swabs for respiratory virus PCR testing were collected during maternal acute febrile respiratory infections, and from infants with any respiratory symptom. We assessed vaccine immunogenicity, safety, and three primary outcomes: the incidence of maternal influenza-like illness in pregnancy and 0-180 days postpartum, the incidence of low birthweight (<2500 g), and the incidence of laboratory-confirmed infant influenza disease from 0 to 180 days. This trial is registered with ClinicalTrials.gov, number NCT01034254.

FINDINGS

From April 25, 2011, to Sept 9, 2013, we enrolled 3693 women in two cohorts of 2090 (1041 assigned to placebo and 1049 to vaccine) and 1603 (805 assigned to placebo and 798 to vaccine), with 3646 liveborn infants (cohort 1, 999 in placebo group and 1010 in vaccine group; cohort 2, 805 in placebo group and 798 in vaccine group). Immunisation reduced maternal febrile influenza-like illness with an overall efficacy of 19% (95% CI 1 to 34) in the combined cohorts; 9% efficacy (-16 to 29) in the first cohort, and 36% efficacy (9 to 55) in the second cohort. For laboratory-confirmed influenza infections in infants aged 0-6 months, immunisation had an overall efficacy for the combined cohorts of 30% (95% CI 5 to 48); in the first cohort, the efficacy was 16% (-19 to 41), and in the second cohort it was 60% (26 to 88). Maternal immunisation reduced the rates of low birthweight by 15% (95% CI 3-25) in both cohorts combined. The rate of small for gestational age infants was not modified by immunisation. The number of adverse events was similar regardless of immunisation status. Miscarriage occurred in three (0·2%) participants in the placebo group versus five (0·3%) in the vaccine group, stillbirth occurred in 31 (1·7%) versus 33 (1·8%), and congenital defects occurred in 18 (1·0%) versus 20 (1·1%). Five women died in the placebo group and three died in the vaccine group. The number of infant deaths at age 0-6 months was similar in each group (50 in the placebo group and 61 in the vaccine group). No serious adverse events were associated with receipt of immunisation.

INTERPRETATION

Year-round maternal influenza immunisation significantly reduced maternal influenza-like illness, influenza in infants, and low birthweight over the entire course of the study, indicating the strategy could be useful in subtropical regions.

FUNDING

Bill & Melinda Gates Foundation.

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.

Complete genome sequence of a KI polyomavirus isolated from an otherwise healthy child with severe lower respiratory tract infection

Unbiased, deep sequencing of a nasal specimen from an otherwise healthy 13-month-old boy hospitalized in intensive care revealed high gene expression and the complete genome of a novel isolate of KI polyomavirus (KIPyV). Further investigation detected minimal gene expression of additional viruses, suggesting that KIPyV was potentially the causal agent. Analysis of the complete genome of isolate NMKI001 revealed it is different from all previously reported genomes and contains two amino acid differences as compared to the closest virus isolate, Stockholm 380 (EF127908). J. Med. Virol. 89:926-930, 2017. © 2016 Wiley Periodicals, Inc.

Human polyomaviruses and incidence of cutaneous squamous cell carcinoma in the New Hampshire skin cancer study

Squamous cell carcinoma (SCC) of the skin is a malignancy arising from epithelial keratinocytes. Experimental and epidemiologic evidence raise the possibility that human polyomaviruses (PyV) may be associated with the occurrence of SCC. To investigate whether the risk for SCC was associated with PyV infection, seropositivity to 10 PyV types was assessed following diagnosis in a population-based case-control study conducted in the United States. A total of 253 SCC cases and 460 age group and gender-matched controls were included. Antibody response against each PyV was measured using a multiplex serology-based glutathione S-transferase capture assay of recombinantly expressed VP1 capsid proteins. Odds ratios (OR) for SCC associated with seropositivity to each PyV type were estimated using logistic regression, with adjustment for potentially confounding factors. SCC cases were seropositive for a greater number of PyVs than controls (P = 0.049). Those who were JC seropositive had increased odds of SCC when compared to those who were JC seronegative (OR = 1.37, 95% CI: 0.98-1.90), with an increasing trend in SCC risk with increasing quartiles of seroreactivity (P for trend = 0.04). There were no clear associations between SCC risk and serostatus for other PyV types. This study provides limited evidence that infection with certain PyVs may be related to the occurrence of SCC in the general population of the United States.

No Evidence of Human Polyomavirus 9, WU and KI DNA in Kidney and Urinary Bladder Tumour Tissue Samples

BACKGROUND/AIMS

The oncogenic potential of human polyomaviruses (HPyVs) has been proposed, but so far only Merkel cell carcinoma polyomavirus seems to be associated with a human tumour. The role of BK polyomavirus (BKPyV) in human tumourigenesis remains controversial. BKPyV establishes persistent infection in the urinary tract, and renal and bladder neoplasms have been studied extensively, but conflicting prevalence data are reported. KI, WU and HPyV9 were detected in urine samples suggesting that these viruses may also infect the urinary tract, but their presence in urinary tract tumours has not been studied. The aim of this work was to examine the prevalence of KIPyV, WUPyV, HPyV9 and BKPyV by PCR in renal and bladder neoplasms.

METHODS

A total of 190 formalin-fixed paraffin-embedded renal neoplasms, bladder cancer and kidney biopsy samples were analysed for the presence of BKPyV, KIPyV, WUPyV and HPyV9 DNA by real-time and nested PCR.

RESULTS

Amplifiable DNA was extracted from all the samples, but none of the studied viruses were detected in benign renal neoplasia (0/23), malignant renal tumours (0/89) or bladder cancer (0/76).

CONCLUSION

Our study did not find any evidence that BKPyV, KIPyV, WUPyV or HPyV9 are associated with bladder and renal tumours.

Polyomaviruses BK, JC, KI, WU, MC, and TS in children with allogeneic hematopoietic stem cell transplantation

Timely and reliable detection of viruses is of key importance in early diagnosis of infection(s) following allogeneic HSCT. Among the immunocompetent, infections with BKPyV and JCPyV are mostly subclinical, while post-HSCT, the former may cause HC and the latter PML. The epidemiology and clinical impact of the newly identified KIPyV, WUPyV, MCPyV, and TSPyV in this context remain to be defined. To assess the incidence and clinical impact of BKPyV, JCPyV, KIPyV, WUPyV, MCPyV, and TSPyV infections, we performed longitudinal molecular surveillance for DNAemias of these HPyVs among 53 pediatric HSCT recipients. Surveillance pre-HSCT and for three months post-HSCT revealed BKPyV DNAemia in 20 (38%) patients. Our data demonstrate frequent BKPyV DNAemia among pediatric patients with HSCT and the confinement of clinical symptoms to high copy numbers alone. MCPyV and JCPyV viremias occurred at low and TSPyV viremia at very low prevalences. KIPyV or WUPyV viremias were not demonstrable in this group of immunocompromised patients.

Characterization of the non-coding control region of polyomavirus KI isolated from nasopharyngeal samples from patients with respiratory symptoms or infection and from blood from healthy blood donors in Norway

Seroepidemiological studies showed that the human polyomavirus KI (KIPyV) is common in the human population, with age-specific seroprevalence ranging from 40-90 %. Genome epidemiological analyses demonstrated that KIPyV DNA is predominantly found in respiratory tract samples of immunocompromised individuals and children suffering from respiratory diseases, but viral sequences have also been detected in brain, tonsil, lymphoid tissue studies, plasma, blood and faeces. Little is known about the sequence variation in the non-coding control region of KIPyV variants residing in different sites of the human body and whether specific strains dominate in certain parts of the world. In this study, we sequenced the non-coding control region (NCCR) of naturally occurring KIPyV variants in nasopharyngeal samples from patients with respiratory symptoms or infection and in blood from healthy donors in Norway. In total 86 sequences were obtained, 44 of which were identical to the original isolated Stockholm 60 variant. The remaining NCCRs contained one or several mutations, none of them previously reported. The same mutations were detected in NCCRs amplified from blood and nasopharyngeal samples. Some patients had different variants in their specimens. Transient transfection studies in HEK293 cells with a luciferase reporter plasmid demonstrated that some single mutations had a significant effect on the relative early and late promoter strength compared with the Stockholm 60 promoter. The effect of the NCCR mutations on viral replication and possible virulence properties remains to be established.

European perspective on human polyomavirus infection, replication and disease in solid organ transplantation

Human polyomaviruses (HPyVs) are a growing challenge in immunocompromised patients in view of the increasing number of now 12 HPyV species and their diverse disease potential. Currently, histological evidence of disease is available for BKPyV causing nephropathy and haemorrhagic cystitis, JCPyV causing progressive multifocal leukoencephalopathy and occasionally nephropathy, MCPyV causing Merkel cell carcinoma and TSPyV causing trichodysplasia spinulosa, the last two being proliferative skin diseases. Here, the current role of HPyV in solid organ transplantation (SOT) was reviewed and recommendations regarding screening, monitoring and intervention were made. Pre-transplant screening of SOT donor or recipient for serostatus or active replication is currently not recommended for any HPyV. Post-transplant, however, regular clinical search for skin lesions, including those associated with MCPyV or TSPyV, is recommended in all SOT recipients. Also, regular screening for BKPyV replication (e.g. by plasma viral load) is recommended in kidney transplant recipients. For SOT patients with probable or proven HPyV disease, reducing immunosuppression should be considered to permit regaining of immune control. Antivirals would be desirable for treating proven HPyV disease, but are solely considered as adjunct local treatment of trichodysplasia spinulosa, whereas surgical resection and chemotherapy are key in Merkel cell carcinoma. Overall, the quality of the clinical evidence and the strength of most recommendations are presently limited, but are expected to improve in the coming years.

Human polyomavirus type six in respiratory samples from hospitalized children with respiratory tract infections in Beijing, China

Background

HPyV6 is a novel human polyomavirus (HPyV), and neither its natural history nor its prevalence in human disease is well known. Therefore, the epidemiology and phylogenetic status of HPyV6 must be systematically characterized.

Methods

The VP1 gene of HPyV6 was detected with an established TaqMan real-time PCR from nasopharyngeal aspirate specimens collected from hospitalized children with respiratory tract infections. The HPyV6-positive specimens were screened for other common respiratory viruses with real-time PCR assays.

Results

The prevalence of HPyV6 was 1.7 % (15/887), and children ≤ 5 years of age accounted for 80 % (12/15) of cases. All 15 HPyV6-positive patients were coinfected with other respiratory viruses, of which influenza virus A (IFVA) (8/15, 53.3 %) and respiratory syncytial virus (7/15, 46.7 %) were most common. All 15 HPyV6-positive patients were diagnosed with lower respiratory tract infections, and their viral loads ranged from 1.38 to 182.42 copies/μl nasopharyngeal aspirate specimen. The most common symptoms were cough (100 %) and fever (86.7 %). The complete 4926-bp genome (BJ376 strain, GenBank accession number KM387421) was amplified and showed 100 % identity to HPyV6 strain 607a.

Conclusions

The prevalence of HPyV6 was 1.7 % in nasopharyngeal aspirate specimens from hospitalized children with respiratory tract infections, as analyzed by real-time PCR. Because the coinfection rate was high and the viral load low, it was not possible to establish a correlation between HPyV6 and respiratory diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-015-0390-5) contains supplementary material, which is available to authorized users.

Antiviral T-cell therapy

Serious viral infections are a common cause of morbidity and mortality after allogeneic stem cell transplantation. They occur in the majority of allograft recipients and are fatal in 17–20%. These severe infections may be prolonged or recurrent and add substantially to the cost, both human and financial, of the procedure. Many features of allogeneic stem cell transplantation contribute to this high rate of viral disease. The cytotoxic and immunosuppressive drugs administered pretransplant to eliminate the host hematopoietic/immune system and any associated malignancy, the delay in recapitulating immune ontogeny post‐transplant, the immunosuppressive drugs given to prevent graft versus host disease (GvHD), and the effects of GvHD itself, all serve to make stem cell transplant recipients vulnerable to disease from endogenous (latent) and exogenous (community) viruses, and to be incapable of controlling them as quickly and effectively as most normal individuals.

Detection of KI WU and Merkel cell polyomavirus in respiratory tract of cystic fibrosis patients

In the last few years, many reports have confirmed the presence of WU, KI and Merkel cell (MC) polyomaviruses (PyV) in respiratory samples wordwide, but their pathogenic role in patients with underlying conditions such as cystic fibrosis is still debated. To determine the prevalence of MCPyV, WUPyV and KIPyV, we conducted a 1-year-long microbiological testing of respiratory specimens from 93 patients with cystic fibrosis in Brescia, Italy. We detected PyV DNA in 94 out of 337 analysed specimens. KIPyV was the most common virus detected (12.1%), followed by WUPyV (8.9%) and MCPyV (6.8%). We found an intriguing association between the presence of MCPyV and the concurrent isolation of Pseudomonas aeruginosa, as well as with the patient status, classified as chronically colonized with P. aeruginosa. Our study adds perspective on the prevalence and the potential pathogenic role of PyV infections.

WU and KI polyomaviruses in respiratory, blood and urine samples from renal transplant patients

BACKGROUND

It is suggested that immunosuppression due to transplantation might be a risk for human polyomavirus KI (KIPyV) and WU (WUPyV) infection. Most of the publications report data about stem cell transplant patients, little is known about these virus infections in renal transplant patients.

OBJECTIVES

To study the presence of KIPyV and WUPyV in upper respiratory, plasma and urine samples from renal transplant patients. To analyse clinical and personal data.

STUDY DESIGN

532 respiratory, 503 plasma and 464 urine samples were collected from 77 renal transplant patients. KIPyV and WUPyV were detected by nested and quantitative real-time PCR. Patient and clinical data from medical records were analyzed.

RESULTS

KIPyV was detected in respiratory, plasma and urine samples from 14.3%, 3.9% and 4.1% of renal transplant patients. WUPyV was found in respiratory and plasma specimens from 9.1% and 5.3% of the patients. Significant association was revealed between the detection of KIPyV and WUPyV and the time of samples collection and the age of the patients. KIPyV was presented in respiratory and plasma sample at the same time. KIPyV was detected in plasma samples from two patients and in urine samples of three other patients providing also KIPyV positive respiratory samples at the same time. No clinical consequences of KIPyV or WUPyV infection were found.

CONCLUSION

Although no clinical consequences of KIPyV and WUPyV infections were found in renal transplant patients, it is suggested that renal transplantation might result in higher susceptibility or reactivation of these infection.

The human polyomaviruses KI and WU: virological background and clinical implications

In 2007, two novel polyomaviruses KI and WU were uncovered in the respiratory secretions of children with acute respiratory symptoms. Seroepidemiological studies showed that infection by these viruses is widespread in the human population. Following these findings, different biological specimens and body compartments have been screened by real-time PCR in the attempt to establish a pathogenetic role for KI polyomavirus (KIPyV) and WU polyomavirus (WUPyV) in human diseases. Although both viruses have been found mainly in respiratory tract samples of immunocompromised patients, a clear causative link with the respiratory disease has not been established. Indeed, the lack of specific clinical or radiological findings, the frequent co-detection with other respiratory pathogens, the detection in subjects without signs or symptoms of respiratory disease, and the variability of the viral loads measured did not allow drawing a definitive conclusion. Prospective studies carried out on a large sample size including both immunocompromised and immunocompetent patients with and without respiratory symptoms are needed. Standardized quantitative real-time PCR methods, definition of a clear clinical cutoff value, timing in the collection of respiratory samples, are also crucial to understand the pathogenic role, if any, of KIPyV and WUPyV in human pathology.

Rare and emerging viral infections in transplant recipients

Emerging viral pathogens include newly discovered viruses as well as previously known viruses that are either increasing, or threatening to increase in incidence. While often first identified in the general population, they may affect transplant recipients, in whom their manifestations may be atypical or more severe. Enhanced molecular methods have increased the rate of viral discovery but have not overcome the problem of demonstrating pathogenicity. At the same time, improved clinical diagnostic methods have increased the detection of reemerging viruses in immunocompromised patients. In this review, we first discuss viral diagnostics and the developing field of viral discovery and then focus on rare and emerging viruses in the transplant population: human T-cell leukemia virus type 1; hepatitis E virus; bocavirus; KI and WU polyomaviruses; coronaviruses HKU1 and NL63; influenza, H1N1; measles; dengue; rabies; and lymphocytic choriomeningitis virus. Detection and reporting of such rare pathogens in transplant recipients is critical to patient care and improving our understanding of posttransplant infections.

Human polyomavirus reactivation: disease pathogenesis and treatment approaches

JC and BK polyomaviruses were discovered over 40 years ago and have become increasingly prevalent causes of morbidity and mortality in a variety of distinct, immunocompromised patient cohorts. The recent discoveries of eight new members of the Polyomaviridae family that are capable of infecting humans suggest that there are more to be discovered and raise the possibility that they may play a more significant role in human disease than previously understood. In spite of this, there remains a dearth of specific therapeutic options for human polyomavirus infections and an incomplete understanding of the relationship between the virus and the host immune system. This review summarises the human polyomaviruses with particular emphasis on pathogenesis in those directly implicated in disease aetiology and the therapeutic options available for treatment in the immunocompromised host.

Fourth European Conference on Infections in Leukaemia (ECIL-4): guidelines for diagnosis and treatment of human respiratory syncytial virus, parainfluenza virus, metapneumovirus, rhinovirus, and coronavirus

Community-acquired respiratory virus (CARV) infections have been recognized as a significant cause of morbidity and mortality in patients with leukemia and those undergoing hematopoietic stem cell transplantation (HSCT). Progression to lower respiratory tract infection with clinical and radiological signs of pneumonia and respiratory failure appears to depend on the intrinsic virulence of the specific CARV as well as factors specific to the patient, the underlying disease, and its treatment. To better define the current state of knowledge of CARVs in leukemia and HSCT patients, and to improve CARV diagnosis and management, a working group of the Fourth European Conference on Infections in Leukaemia (ECIL-4) 2011 reviewed the literature on CARVs, graded the available quality of evidence, and made recommendations according to the Infectious Diseases Society of America grading system. Owing to differences in screening, clinical presentation, and therapy for influenza and adenovirus, ECIL-4 recommendations are summarized for CARVs other than influenza and adenovirus.