Polyomaviruses KI and WU in immunocompromised patients with respiratory disease

Prevalence of Respiratory Polyomaviruses Among Pediatric Patients With Respiratory Symptoms in Singapore

Background: Although WU polyomavirus (WU) and KI polyomavirus (KI) have been demonstrated to infect the human respiratory tract, it remains unclear if WU or KI cause human disease. We sought to further investigate the relationship between WU and KI infection and respiratory disease in a pediatric population with respiratory symptoms in Singapore. Methods: We conducted a cross-sectional study of pediatric patients with respiratory symptoms in a Singaporean pediatrics hospital. Upon consent, residual respiratory samples from pediatric inpatients, previously screened for common respiratory viruses, were collected and further screened for WU and KI using qPCR. The amplicons of positive samples were sequenced for confirmation. The severity of a patient's illness was assessed by chart review post-discharge looking for clinical markers of respiratory status such as presenting symptoms, diagnoses, and interventions. Results: From December 2016 to April 2017, 201 patients with residual respiratory samples were enrolled in the study. The average age of all participants recruited was 45 months. WU and KI were detected in 13% (26/201) and 3% (6/201) of patients, respectively. Conducting bivariate and multivariate modeling, patients with WU or KI positivity were not at increased risk of SARI, need for additional oxygen, intravenous fluids, and did not receive additional oral antibiotics or bronchodilators during admission. In contrast, patients with RSV detections were at increased risk of requiring supplemental oxygen during hospital admission. Conclusion: While limited in sample size, our pilot study data do not support the hypothesis that molecular evidence of WU or KI was associated with increased morbidity among a sample of general, pediatric patients with respiratory illness in Singapore.

Multiple Skin Cancers in a Renal Transplant Recipient: A Patient Report with Analyses of Human Papillomavirus and Human Polyomavirus Infection

Skin cancer is an important complication in renal transplant recipients. Associations of transplant-related skin tumor with ultraviolet radiation, age at transplantation, type of immunosuppressant drug administered, and viral infection have been reported; however, the details remain unclear. We report a 61-year-old man who had underwent renal transplantation at 38 years of age and developed multiple skin tumors or squamous cell carcinomas (SCCs). Polymerase chain reaction (PCR) analyses of the patient's 12 tumors for viral DNAs of cutaneous or mucosal human papillomavirus (HPV) and 6 human polyomaviruses (MCPyV, trichodysplasia spinulosa-associated, BK, JC, KI and WU polyomaviruses) only detected cutaneous HPV-DNA in only 5 of the tumors; no other viruses were detected. Real-time PCR showed high loads of cutaneous HPV in 3 SCCs and very low loads of MCPyV in 9. Immunohistochemistry revealed no tumor cell expression for MCPyV-large T-antigen or mucosal HPV. Our report not only reconfirmed the association of cutaneous HPV5 with skin cancer in renal transplant recipients in previous studies but also showed no relevant association of 6 human polyomaviruses and mucosal HPV with skin tumors.

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.

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.

The novel KI, WU and MC polyomaviruses and human diseases

From 2007 to 2012, the Polyomaviridae family expanded with the discovery of several novel human polyomaviruses. Infection by polyomaviruses is widespread in the human population, but only immunocompromised patients are at risk for disease. Currently, four polyomaviruses have been specifically associated with human diseases: BK polyomavirus, JC polyomavirus, Merkel cell polyomavirus and trichodysplasia spinulosa-associated polyomavirus. The pathogenic potential of the other human polyomaviruses is unknown. This review focuses on the novel Karolinska Institute polyomavirus, Washington University polyomavirus and Merkel cell polyomavirus. Karolinska Institute polyomavirus and Washington University polyomavirus were uncovered in respiratory specimens of children with acute respiratory symptoms. Merkel cell polyomavirus was found in an aggressive skin tumor named Merkel cell carcinoma. The scientific literature concerning the three human polyomaviruses is summarized and discussed including seroepidemiology, detection methods (real-time PCR), histopathological findings and association with clinical manifestations.

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

Routine testing for these viruses in immunocompromised patients is not recommended.

Data are limited regarding 2 new human polyomaviruses, KI polyomavirus (KIPyV) and WU polyomavirus (WUPyV), in immunocompromised patients. We used real-time PCR to test for these and 12 respiratory viruses in 2,732 nasal wash samples collected during the first year after allogeneic hematopoietic cell transplantation from 222 patients. Specimens were collected weekly until day 100; then at least every 3 months. One year after hematopoietic cell transplantation, the cumulative incidence estimate was 26% for KIPyV and 8% for WUPyV. Age <20 years predicted detection of KIPyV (hazard ratio [HR] 4.6) and WUPyV (HR 4.4), and detection of a respiratory virus in the previous 2 weeks predicted KIPyV detection (HR 3.4). Sputum production and wheezing were associated with detection of KIPyV in the past week and WUPyV in the past month. There were no associations with polyomavirus detection and acute graft versus host disease, cytomegalovirus reactivation, neutropenia, lymphopenia, hospitalization, or death.

The role of infections and coinfections with newly identified and emerging respiratory viruses in children

Acute respiratory infections are a major cause of morbidity in children both in developed and developing countries. A wide range of respiratory viruses, including respiratory syncytial virus (RSV), influenza A and B viruses, parainfluenza viruses (PIVs), adenovirus, rhinovirus (HRV), have repeatedly been detected in acute lower respiratory tract infections (LRTI) in children in the past decades. However, in the last ten years thanks to progress in molecular technologies, newly discovered viruses have been identified including human Metapneumovirus (hMPV), coronaviruses NL63 (HcoV-NL63) and HKU1 (HcoV-HKU1), human Bocavirus (HBoV), new enterovirus (HEV), parechovirus (HpeV) and rhinovirus (HRV) strains, polyomaviruses WU (WUPyV) and KI (KIPyV) and the pandemic H1N1v influenza A virus. These discoveries have heavily modified previous knowledge on respiratory infections mainly highlighting that pediatric population is exposed to a variety of viruses with similar seasonal patterns. In this context establishing a causal link between a newly identified virus and the disease as well as an association between mixed infections and an increase in disease severity can be challenging. This review will present an overview of newly recognized as well as the main emerging respiratory viruses and seek to focus on the their contribution to infection and co-infection in LRTIs in childhood.

Detection of KI polyomavirus and WU polyomavirus DNA by real-time polymerase chain reaction in nasopharyngeal swabs and in normal lung and lung adenocarcinoma tissues

Polyomaviruses KI (KIPyV) and WU (WUPyV) were detected from 7 (3.0%) and 38 (16.4%) of 232 children with respiratory tract infections by real-time PCR. The rates of infection by KIPyV and WUPyV alone were 3 of 7 (42.9%) and 20 of 38 (52.6%), respectively. In the other samples, various viruses (human respiratory syncytial virus, human metapneumovirus, human rhinovirus, parainfluenza virus 1 and human bocavirus) were detected simultaneously. One case was positive for KIPyV, WUPyV and hMPV. There was no obvious difference in clinical symptoms between KIPyV-positive and WUPyV-positive patients with or without coinfection. KIPyV was detected in one of 30 specimens of lung tissue (3.3%). Neither of the viruses was detected in 30 samples of lung adenocarcinoma tissue.

Prevalence of polyomaviruses and links with human diseases

The simian virus 40 and murine polyomaviruses were shown to be DNA tumor viruses in their natural hosts and/or heterologous experimental hosts in the mid-20th Century. The first two human polyomaviruses, the BK polyomavirus and JC polyomavirus, were discovered in 1971 and were shown to induce severe disease in immunocompromised patients, but their involvement in human cancers is still a matter for debate. The discovery of a polyomavirus associated with Merkel cell carcinoma (Merkel cell polyomavirus) in 2008 resulted in a renewed interest in the Polyomaviridae family, leading to the discovery of new human polyomaviruses. This review addresses the involvement of the nine human polyomaviruses and simian virus 40 in human diseases, with a particular focus on their prevalence and the humoral response directed against structural antigens in the general population and in subjects presenting specific diseases.

Changing epidemiology of respiratory viral infections in hematopoietic cell transplant recipients and solid organ transplant recipients

PURPOSE OF REVIEW

New respiratory viruses have been discovered in recent years and new molecular diagnostic assays have been developed that improve our understanding of respiratory virus infections. This article will review the changing epidemiology of these viruses after hematopoietic stem cell and solid organ transplantation.

RECENT FINDINGS

Respiratory viruses are frequently detected in transplant recipients. A number of viruses have been newly discovered or emerged in the last decade, including human metapneumovirus, human bocavirus, new human coronaviruses and rhinoviruses, human polyomaviruses, and a new 2009 pandemic strain of influenza A/H1N1. The potential for these viruses to cause lower respiratory tract infections after transplantation varies, and is greatest for human metapneumovirus and H1N1 influenza, but appears to be limited for the other new viruses. Acute and long-term complications in hematopoietic and solid organ transplant recipients are active areas of research.

SUMMARY

Respiratory viral infections are frequently associated with significant morbidity following transplantation and are therefore of great clinical and epidemiologic interest. As new viruses are discovered, and more sensitive diagnostic methods are developed, defining the full impact of emerging respiratory viruses in transplant recipients must be elucidated by well designed clinical studies.

WU and KI polyomavirus infections in pediatric hematology/oncology patients with acute respiratory tract illness

Background

WU and KI polyomaviruses (PyV) were discovered in 2007 in respiratory tract samples in adults and children. Other polyomaviruses (BKPyV and JCPyV) have been associated with illness in immunocompromised patients, and some studies suggest a higher prevalence of WUPyV and KIPyV in this population.

Objective

To determine whether a higher prevalence or viral load for WUPyV and KIPyV exists in immunocompromised children compared with immunocompetent children.

Study design

We measured the prevalence and viral load of WU and KI PyV by quantitative real-time PCR of viral DNA in respiratory tract specimens from pediatric hematology/oncology patients and immunocompetent controls with acute respiratory illnesses.

Results

The prevalence of WUPyV in the immunocompromised population was 5/161 (3%) versus 14/295 (5%) in the control population (P = 0.5), and 9/161 (5.6%) versus 7/295 (2.3%) respectively for KIPyV (P = 0.13). The mean viral load (in copies per cell or mL of sample) for KIPyV, was higher in the immunocompromised group compared to the control group (P = 0.019), but was not statistically different for WUPyV. A higher prevalence was seen in the hematopoietic stem cell transplant recipients compared with other immunocompromised patients (6/26 versus 3/43, P = 0.054). Viral persistence was demonstrated only in 1/25 (4%) of sequential samples for KIPyV, and no persistence was seen for WUPyV.

Conclusions

A higher prevalence of WUPyV or KIPyV in the immunocompromised population compared with the immunocompetent group was not demonstrated. Higher viral loads for KIPyV in the immunocompromised group may suggest an increased pathogenic potential in this population.

KI and WU polyomaviruses and CD4+ cell counts in HIV-1-infected patients, Italy

To investigate an association between KI and WU polyomavirus (KIPyV and WUPyV) infections and CD4+ cell counts, we tested HIV-1–positive patients and blood donors. No association was found between cell counts and virus infections in HIV-1–positive patients. Frequency of KIPyV infection was similar for both groups. WUPyV was more frequent in HIV-1–positive patients.

Identification of WU polyomavirus from pediatric patients with acute respiratory infections in Beijing, China

A novel polyomavirus (WU virus) has been identified in pediatric patients with acute respiratory tract infections (ARI), but its role as a respiratory pathogen has not yet been demonstrated. To investigate if WU virus is related to acute respiratory infections in infants and children in Beijing, specimens collected from 674 pediatric patients with ARI from April 2007 to May 2008 and from 202 children without ARI were used for this investigation. Common respiratory viruses were tested by virus isolation and/or antigen detection by indirect immunofluorescent assay followed by RT-PCR or PCR for other viruses associated with respiratory infections in specimens collected from patients with ARI before WU virus DNA was detected. WU virus DNA was detected by initial screening and secondary confirmation PCR for all specimens. The region encoding the VP2 gene of the virus was amplified from 17 WU-virus-positive clinical specimens, and sequence analysis was performed. Thirty-eight of 674 (5.6%) specimens from patients with ARI and 3 of 202 (1.5%) specimens from children without ARI yielded PCR products with the predicted molecular weight, using either screening or confirmation primer sets, indicating that these specimens were WU virus positive. However, more than 60% of the 38 WU-virus-positive specimens from patients with ARI were also positive for one or more respiratory viruses. The nucleotide and deduced amino acid sequences of the region encoding the VP2 gene from 17 Beijing WU viruses shared high homology (>98.5%) with sequences from GenBank and among themselves. The data indicated that WU virus in Beijing occurred 3.7 times more frequently in pediatric patients with ARI than in those without ARI (p < 0.05).

Serologic evidence of frequent human infection with WU and KI polyomaviruses

WU polyomavirus (WUPyV) and KI polyomavirus (KIPyV) are novel human polyomaviruses. They were originally identified in human respiratory secretions, but the extent of human infection caused by these viruses has not been described to date. To determine the seroepidemiology of WUPyV and KIpyIV, we used an ELISA to screen serum samples from 419 patients at the St. Louis Children's Hospital and Barnes-Jewish Hospital during 2007-2008. The age-stratified deidentified samples were examined for antibodies to the major capsid proteins of WUPyV and KIPyV. Seropositivity for each virus was similar; antibody levels were high in the youngest age group (<6 months), decreased to a nadir in the next age group (6 to <12 months), and then steadily increased with subsequent age groups, eventually reaching a plateau of approximate, equals 80% for WUPyV and approximate, equals 70% for KIPyV. These results demonstrate that both KIPyV and WUPyV cause widespread infection in the human population.

Merkel cell polyomavirus DNA in tumor-free tonsillar tissues and upper respiratory tract samples: implications for respiratory transmission and latency

Background

Merkel cell polyomavirus (MCPyV) was discovered recently. It is considered a potential causative agent of Merkel cell carcinoma, a life-threatening skin cancer.

Objectives

To study the prevalence of MCPyV in a large number of clinical samples of various types. Most of the samples were examined also for the other newly found polyomaviruses KI (KIPyV) and WU (WUPyV).

Study design

Altogether 1390 samples from immunocompetent or immunocompromised patients, including (i) tonsillar tissues and sera from tonsillectomy patients; (ii) nasopharyngeal aspirates (NPAs) and sera from wheezing children and (iii) nasal swabs, sera and stools from febrile leukemic children were studied for MCPyV. The tonsils, nasal swabs and stools were also studied for KIPyV and WUPyV.

Results

MCPyV DNA was detected in 14 samples altogether; 8 of 229 (3.5%) tonsillar tissues, 3 of 140 (2.1%) NPAs, 2 of 106 (1.9%) nasal swabs and 1 of 840 (0.1%) sera. WUPyV and KIPyV were detected in 5 (2.2%) and 0 tonsils, 1 (0.9%) and 4 (3.8%) nasal swabs and 0 and 2 (2.7%) fecal samples, respectively. The patients carrying in tonsils MCPyV were of significantly higher age (median 42 years) than those carrying WUPyV (4 years, p < 0.001).

Conclusions

MCPyV DNA occurs in tonsils more frequently in adults than in children. By contrast, WUPyV DNA is found preferentially in children. MCPyV occurs also in nasal swabs and NPAs, in a frequency similar to that of KIPyV and WUPyV. The tonsil may be an initial site of WUPyV infection and a site of MCPyV persistence.