Multiplex real-time PCR for the simultaneous detection of herpes simplex virus, human herpesvirus 6, and human herpesvirus 7

Update on human herpesvirus 7 pathogenesis and clinical aspects as a roadmap for future research

Human herpesvirus 7 (HHV-7) is a common virus that is associated with various human diseases including febrile syndromes, dermatological lesions, neurological defects, and transplant complications. Still, HHV-7 remains one of the least studied members of all human betaherpesviruses. In addition, HHV-7-related research is mostly confined to case reports, while in vitro or in vivo studies unraveling basic virology, transmission mechanisms, and viral pathogenesis are sparse. Here, we discuss HHV-7-related literature linking clinical syndromes to the viral life cycle, epidemiology, and viral immunopathogenesis. Based on our review, we propose a hypothetical model of HHV-7 pathogenesis inside its host. Furthermore, we identify important knowledge gaps and recommendations for future research to better understand HHV-7 diseases and improve therapeutic interventions.

Performance evaluation of the SMG HHV-6 Q Real-Time PCR Kit for quantitative detection and differentiation of human herpesvirus 6A and 6B

The aim of this study was to compare the performance of the newly developed SMG HHV-6 Q Real-Time PCR Kit (SMG assay) with the RealStar HHV-6 PCR Kit (RealStar assay). The analytical sensitivity and specificity, linearity, and precision of the SMG assay were evaluated. The clinical performance of the SMG assay was assessed and compared with that of the RealStar assay using 207 clinical specimens (HHV-6A positive, n = 51; HHV-6B positive, n = 64; HHV-6A/B negative, n = 92). The limit of detection of the SMG assay was 2.92 log10 copies/mL for HHV-6A DNA and 2.88 log10 copies/mL for HHV-6B DNA. The linear range was determined to be 3.40-9.00 log10 copies/mL for both viruses. Intra- and inter-assay variability were below 5% at concentrations ranging from 4 to 9 log10 copies/mL. No cross-reactivity was observed with the 25 microorganisms included in the specificity panel. The clinical sensitivity and specificity of the SMG and RealStar assays compared to in-house polymerase chain reaction and sequencing were as follows: SMG assay, 98.0% and 100% for HHV-6A DNA, respectively, and 96.9% and 100% for HHV-6B DNA, respectively; RealStar assay, 98.0% and 100% for HHV-6A DNA, respectively, and 90.6% and 100% for HHV-6B DNA, respectively. The correlation coefficients between viral loads measured by the two assays were 0.948 and 0.975, with mean differences of 0.62 and 0.32 log10 copies/mL for HHV-6A and HHV-6B DNA, respectively. These results demonstrate that the SMG assay is a sensitive and reliable tool for the quantitative detection and differentiation of HHV-6A and HHV-6B DNA.IMPORTANCEQuantitative real-time PCR (qPCR) that can distinguish between HHV-6A and HHV-6B DNA is recommended for diagnosis of active infection. The SMG HHV-6 Q Real-Time PCR Kit (SMG assay) is a newly developed qPCR assay that can differentiate between HHV-6A and HHV-6B DNA; however, little is known about its performance. In this study, we assessed the performance of the SMG assay and compared it with that of a commercially available qPCR assay, the RealStar HHV-6 PCR Kit (RealStar assay). The SMG assay demonstrated excellent analytical sensitivity and specificity, precision, and linearity. Furthermore, the viral loads measured by the SMG assay were highly correlated with those measured by the RealStar assay. Our results suggest that the SMG assay is a useful diagnostic tool for quantitative detection and differentiation of HHV-6A and HHV-6B DNA.

Detection of Human Herpesviruses in Sera and Saliva of Asymptomatic HIV-Infected Individuals Using Multiplex RT-PCR DNA Microarray

Human herpesviruses (HHVs) are frequently linked to an increased risk of acquiring human immunodeficiency virus (HIV), and vice versa. This study aimed to detect human herpesvirus (HHV) members in the sera and saliva of asymptomatic HIV-infected individuals. Paired saliva and serum samples were obtained from 30 asymptomatic HIV-infected individuals. HHVs were detected with a multiplex reverse transcription-polymerase chain reaction (RT-PCR) DNA microarray Clart®Entherpex kit. A total of 30 subjects were enrolled: 23 (76.67%) men and 7 (23.33%) women. The present study showed that at least one or more HHV members were detected in the saliva and sera of all (100%) of the subjects. In the saliva, we detected herpes simplex virus 1 (HSV-1) 6.67%, herpes simplex virus 2 (HSV-2) 6.67%, Epstein-Barr virus (EBV) 86.67%, cytomegalovirus (CMV) 63.33%, HHV-6 (40%), and HHV-7 (83.33%). In the sera, HSV-2 (20%), EBV (30%), CMV (40%), HHV-6 (0%), and HHV-7 (76.67%) were found, but not HSV-1. VZV and HHV-8 were not detected in either the saliva or sera. EBV and HHV6 were significantly more prevalent in the saliva than they were in the sera of asymptomatic HIV-infected individuals (p < 0.05). However, no significant differences were found in the prevalence of HSV-1, EBV, CMV, HHV-6, and HHV-7 in the saliva and sera of asymptomatic HIV-infected individuals (p > 0.05). In conclusion, the multiplex RT-PCR DNA microarray can serve as a valuable diagnostic tool that can be used as a screening tool or a first-line test for HHVs infections.

Herpesvirus infections in adenoids in patients with chronic adenotonsillar disease

Adenoids and tonsils have gained interest as a new in vivo model to study local immune functions and virus reservoirs. Especially herpesviruses are interesting because their prevalence and persistence in local lymphoid tissue are incompletely known. Our aim was to study herpesvirus and common respiratory virus infections in nonacutely ill adenotonsillar surgery patients. Adenoid and/or palatine tonsil tissue and nasopharyngeal aspirate (NPA) samples were collected from elective adenoidectomy (n = 45) and adenotonsillectomy (n = 44) patients (median age: 5, range: 1–20). Real‐time polymerase chain reaction was used to detect 22 distinct viruses from collected samples. The overall prevalence of herpesviruses was 89% and respiratory viruses 94%. Human herpesviruses 6 (HHV6), 7 (HHV7), and Epstein–Barr virus (EBV) were found, respectively, in adenoids (33%, 26%, 25%), tonsils (45%, 52%, 23%), and NPA (46%, 38%, 25%). Copy numbers of the HHV6 and HHV7 genome were significantly higher in tonsils than in adenoids. Patients with intra‐adenoid HHV6 were younger than those without. Detection rates of EBV and HHV7 showed agreement between corresponding sample types. This study shows that adenoid and tonsil tissues commonly harbor human herpes‐ and respiratory viruses, and it shows the differences in virus findings between sample types.

MicroRNA expression profiling of cerebrospinal fluid/serum exosomes in children with human herpesvirus 6-associated encephalitis/encephalopathy by high-throughput sequencing

Primary human herpesvirus 6 (HHV-6) infection is sometimes accompanied by acute encephalopathy with reduced subcortical diffusion (AED) in immunocompetent children. We investigated exosomal microRNA (miRNA) expression profiles in cerebrospinal fluid (CSF) and sera of patients with HHV-6-associated AED (n = 5) and febrile seizure (FS) (n = 5) using high-throughput sequencing. A total of 176 and 663 miRNAs were identified in CSF and serum exosomes, respectively. Comparative analysis determined that some miRNAs (miR-381-3p, miR-155) were exclusively expressed in the CSF exosomes of AED but not of FS patients, suggesting their potential application as novel diagnostic biomarkers for AED.

Detection of Major Human Herpesviruses in Iranian Patients with Suspected Encephalitis Using Multiplex Polymerase Chain Reaction

BACKGROUND

The Herpesviridae family plays a significant etiological role in central nervous system viral infections during primary infection or reactivation from a latent form. Early detection is crucial because prescribing some antivirals can prevent severe side effects or life-threatening conditions.

METHODS

In this study, 251 CSF specimens were collected from patients with clinical suspicion of viral encephalitis in Pars Hospital, Tehran, Iran. DNA was extracted, and a multiplex PCR was designed to investigate the presence of herpes simplex virus-1, herpes simplex virus-2, varicella zoster virus, Epstein-Barr virus, and cytomegalovirus.

RESULTS

Overall, 59 cases of the 251 CSF samples were positive for multiplex PCR (23.5%). The most frequent positive findings were EBV and HSV, with a prevalence of 10.3% and 8.7% (5.5% HSV-1 and 3.1% HSV-2), respectively. Four co-infections were also seen in this study.

CONCLUSIONS

This multiplex PCR assay detects simultaneously different herpesviruses in CSF samples of patients with suspected encephalitis in 2 rounds of PCR amplification; therefore, it is a reliable and cost-saving diagnostic method for evaluating patients infected with herpesvirus with neurological disorders.

HERQ-9 Is a New Multiplex PCR for Differentiation and Quantification of All Nine Human Herpesviruses

By adulthood, almost all humans become infected by at least one herpesvirus (HHV). The maladies inflicted by these microbes extend beyond the initial infection, as they remain inside our cells for life and can reactivate, causing severe diseases. The diagnosis of active infection by these ubiquitous pathogens includes the detection of DNA with sensitive and specific assays. We developed the first quantitative PCR assay (HERQ-9) designed to identify and quantify each of the nine human herpesviruses. The simultaneous detection of HHVs in the same sample is important since they may act together to induce life-threatening conditions. Moreover, the high sensitivity of our method is of extreme value for assessment of the effects of these viruses persisting in our body and their long-term consequences on our health.

Infections with the nine human herpesviruses (HHVs) are globally prevalent and characterized by lifelong persistence. Reactivations can potentially manifest as life-threatening conditions for which the demonstration of viral DNA is essential. In the present study, we developed HERQ-9, a pan-HHV quantitative PCR designed in triplex reactions to differentiate and quantify each of the HHV-DNAs: (i) herpes simplex viruses 1 and 2 and varicella-zoster virus; (ii) Epstein-Barr virus, human cytomegalovirus, and Kaposi’s sarcoma-associated herpesvirus; and (iii) HHV-6A, -6B, and -7. The method was validated with prequantified reference standards as well as with mucocutaneous swabs and cerebrospinal fluid, plasma, and tonsillar tissue samples. Our findings highlight the value of multiplexing in the diagnosis of many unsuspected, yet clinically relevant, herpesviruses. In addition, we report here frequent HHV-DNA co-occurrences in clinical samples, including some previously unknown. HERQ-9 exhibited high specificity and sensitivity (LOD₉₅s of ∼10 to ∼17 copies/reaction), with a dynamic range of 10¹ to 10⁶ copies/μl. Moreover, it performed accurately in the coamplification of both high- and low-abundance targets in the same reaction. In conclusion, we demonstrated that HERQ-9 is suitable for the diagnosis of a plethora of herpesvirus-related diseases. Besides its significance to clinical management, the method is valuable for the assessment of hitherto-unexplored synergistic effects of herpesvirus coinfections. Furthermore, its high sensitivity enables studies on the human virome, often dealing with minute quantities of persisting HHVs.

IMPORTANCE By adulthood, almost all humans become infected by at least one herpesvirus (HHV). The maladies inflicted by these microbes extend beyond the initial infection, as they remain inside our cells for life and can reactivate, causing severe diseases. The diagnosis of active infection by these ubiquitous pathogens includes the detection of DNA with sensitive and specific assays. We developed the first quantitative PCR assay (HERQ-9) designed to identify and quantify each of the nine human herpesviruses. The simultaneous detection of HHVs in the same sample is important since they may act together to induce life-threatening conditions. Moreover, the high sensitivity of our method is of extreme value for assessment of the effects of these viruses persisting in our body and their long-term consequences on our health.

HHV-6-Associated Neurological Disease in Children: Epidemiologic, Clinical, Diagnostic, and Treatment Considerations

Human herpesviruses 6A and 6B, often referred to collectively as human herpesvirus 6, are a pair of beta-herpesviruses known to cause a variety of clinical syndromes in both immunocompetent and immunocompromised individuals. Most humans are infected with human herpesvirus 6B, and many with human herpesvirus 6A. Primary infection typically occurs in early childhood, although large-scale reviews on the topic are limited. Herein, the authors explore the clinical manifestations of human herpesvirus 6-associated disease in both immunocompetent and immunocompromised pediatric patients, the risk factors for development of human herpesvirus 6-associated neurological disease, the risk of autoimmunity associated with development of active or latent infection, the relevance of human herpesvirus 6-specific diagnostic tests, and the medications used to treat human herpesvirus 6. The goal of this review is to improve the current understanding of human herpesvirus 6 in pediatric populations and to examine the most effective diagnostic and therapeutic interventions in this disease state.

Simultaneous Detection of Beta and Gamma Human Herpesviruses by Multiplex qPCR Reveals Simple Infection and Coinfection Episodes Increasing Risk for Graft Rejection in Solid Organ Transplantation

Herpesviruses are common components of the human microbiome that become clinically relevant when a competent immunosurveillance is compromised, such as in transplantation. Members of the beta and gamma subfamilies are associated with a wide diversity of pathologies, including end-organ disease and cancer. In this study, we developed a multiplex qPCR technique with high specificity, sensitivity, efficiency and predictability that allowed the simultaneous detection and quantification of beta and gamma human herpesviruses. The technique was tested in a cohort of 34 kidney- or liver-transplanted pediatric patients followed up for up to 12 months post-transplant. Viral load was determined in 495 leukocyte-plasma paired samples collected bi-weekly or monthly. Human herpesvirus (HHV) 7 was the herpesvirus most frequently found in positive samples (39%), followed by Epstein-Barr virus (EBV) (20%). Also, EBV and HHV7 were present in the majority of coinfection episodes (62%). The share of positive samples exclusively detected either in leukocytes or plasma was 85%, suggesting that these herpesviruses tended to take a latent or lytic path in an exclusive manner. Infection by human cytomegalovirus (HCMV) and HHV6, as well as coinfection by EBV/HHV7 and EBV/HHV6/HHV7, were associated with graft rejection (RR = 40.33 (p = 0.0013), 5.60 (p = 0.03), 5.60 (p = 0.03) and 17.64 (p = 0.0003), respectively). The routine monitoring of beta and gamma herpesviruses should be mandatory in transplant centers to implement preventive strategies.

Clinical Correlations of Positive Herpes Simplex PCR in Cerebrospinal Fluid

OBJECTIVES

Herpes simplex viruses (HSV) can produce encephalitis (HSE), which requires early detection, typically using polymerase chain reaction (PCR) in cerebrospinal fluid (CSF). However, other neurological conditions not directly caused by HSV may also present with a positive HSV PCR in the CSF (NCNHPCR+). We aimed to analyze the clinical features of both groups of patients (HSE vs. NCNHPCR+) and to consider the potential relevance of this finding in the latter.

METHODS

A retrospective analysis of clinical presentation, workup (CSF, EEG, and MRI) and outcome of patients with an HSV+ result in CSF was conducted from Jan-2007 to Sep-2015 in our institution. Patients under 18 years and those with nonencephalitic HSV associated disorders were excluded. Group comparison between HSE and NCNHPCR+ patients was conducted using parametric and nonparametric tests accordingly.

RESULTS

Sixteen HSE and 23 NCNHPCR+ patients were included. Patients with HSE presented a higher incidence of headache (87.5% vs. 43.5%; P=0.008), meningeal symptoms (50% vs. 17.4%; P=0.04), pleocytosis (75% vs. 18%; P=0.001), EEG abnormalities (46.67% vs. 22%; P=0.02) and typical MRI findings (50% vs. 0%; P<0.001), whereas 35% of patients with NCNHPCR+ had an underlying immunologic disorder (35% vs. 0%; P=0.012).

CONCLUSIONS

The pathogenic role of HSV in NCNHPCR+ is uncertain. This finding must be interpreted in the appropriate clinical, EEG, and neuroimaging context. Immunocompromise and neuroinflammation states could be related to a higher presence of HSV in CSF.

Virological testing of cerebrospinal fluid in children aged less than 14 years with a suspected central nervous system infection: A retrospective study on 304 consecutive children from January 2012 to May 2015

OBJECTIVE

The study aimed to describe the prevalence of HSV DNA, VZV DNA, Enterovirus RNA, Parechovirus RNA, CMV DNA, EBV DNA, adenovirus DNA, HHV-6 DNA, HHV-7 DNA, HHV-8 DNA and Parvovirus B19DNA in children aged less 14 years with a suspected viral infection of the central nervous system in a clinical practice setting.

METHODS

Between January 2012 and May 2015, cerebrospinal fluids from 304 children were tested with an in-house real-time PCR method.

RESULTS

A positive PCR was detected in 64 subjects (21%): the mean number of tests performed in patients who showed a viral infection was 7.5, significantly higher (p = 0.001) with respect to that reported in negative samples (6.4). Enterovirus is the leading virus detected: 12 out of the 37 positive children reported were newborns (85.7% of all the newborns with a positive result). The second most frequently identified virus was HHV-7 (5 positive PCR out of 105 samples tested, 4.8%, if we excluded a child with a concomitant S. pneumoniae isolated), a prevalence significantly higher with respect to VZV (p = 0.02) and to CMV (p = 0.04). HHV-6 was the third most commonly identified aetiology (4.2%). All children were immunocompetent.

SIGNIFICANCE

Only a minority of children had a specific viral aetiology identified: the rate of HHV-7 positivity suggests a routine testing of these viruses within the diagnostic algorithm in immunocompetent paediatric patients. This approach could help to define the clinical role of this herpesvirus.

Successful Treatment of Corticosteroid with Antiviral Therapy for a Neonatal Liver Failure with Disseminated Herpes Simplex Virus Infection

Background Herpes simplex virus (HSV) infection carries one of the poorest outcomes of neonatal liver failure (NLF). Neonates with disseminated HSV infection can develop hemophagocytic lymphohistiocytosis (HLH), and occasionally need orthotopic liver transplantation. Early interventions may be critical for the cure of NLF. Case Report We describe herewith a 6-day-old neonate with fulminant hepatic failure due to disseminated HSV-1 infection, who successfully responded to high-dose corticosteroid therapy 72 hours after the onset of disease. Preceding acyclovir, gamma globulin, and exchange blood transfusion therapies failed to control the disease. Methylprednisolone pulse therapy led to a drastic improvement of liver function and cytokine storms, and prevented the disease progression to HLH. Sustained levels of plasma and cerebrospinal fluid HSV DNA declined after prolonged acyclovir therapy. Bilateral lesions of the periventricular white matter areas, assessed by magnetic resonance imaging, disappeared at 3 months of age. The infant showed normal growth and development at 4 years of age. Conclusion Early anti-hypercytokinemia therapy using corticosteroid, and prolonged antiviral therapy might only provide the transplantation-free cure of NLF with HSV dissemination.

Optimisation of a quantitative polymerase chain reaction-based strategy for the detection and quantification of human herpesvirus 6 DNA in patients undergoing allogeneic haematopoietic stem cell transplantation

Human herpesvirus 6 (HHV-6) may cause severe complications after haematopoietic stem cell transplantation (HSCT). Monitoring this virus and providing precise, rapid and early diagnosis of related clinical diseases, constitute essential measures to improve outcomes. A prospective survey on the incidence and clinical features of HHV-6 infections after HSCT has not yet been conducted in Brazilian patients and the impact of this infection on HSCT outcome remains unclear. A rapid test based on real-time quantitative polymerase chain reaction (qPCR) has been optimised to screen and quantify clinical samples for HHV-6. The detection step was based on reaction with TaqMan^® hydrolysis probes. A set of previously described primers and probes have been tested to evaluate efficiency, sensitivity and reproducibility. The target efficiency range was 91.4% with linearity ranging from 10-10⁶ copies/reaction and a limit of detection of five copies/reaction or 250 copies/mL of plasma. The qPCR assay developed in the present study was simple, rapid and sensitive, allowing the detection of a wide range of HHV-6 loads. In conclusion, this test may be useful as a practical tool to help elucidate the clinical relevance of HHV-6 infection and reactivation in different scenarios and to determine the need for surveillance.

Clinical application of viral cerebrospinal fluid PCR testing for diagnosis of central nervous system disorders: a retrospective 11-year experience

The cerebrospinal fluid (CSF) polymerase chain reaction (PCR) is the gold standard to detect cerebral viral activity. As positive findings do not prove an impact on the neurological disorder, data interpretation is difficult. To better assess the impact of positive CSF PCR findings in different neurological diseases and to identify coherences facilitating CSF PCR data interpretation, we performed this retrospective analysis of CSF PCR data of 481 pediatric and 2604 adult patients, including herpes simplex virus (HSV), varicella zoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), human herpesvirus 6 (HHV-6), and enteroviruses (EV). Nucleic acid of EBV was detected in 1.6% (39/2449), of VZV in 1.3% (34/2624), of HSV in 1.24% (37/2994), of EV in 0.4% (10/2364), of HHV-6 in 0.17% (4/2417), and of CMV in 0.2% (5/2514) of the patients. Newborns and elderly people showed highest infection rates. HSV, VZV, and EV prevailed in typical infectious central nervous system (CNS) diseases; EBV, in further inflammatory neurological diseases; HSV and EBV, in immunocompromised patients; and EBV, HSV, and HHV-6, in further non-inflammatory neurological diseases. Analysis of successive PCR studies revealed delayed viral detection for EBV (6/147) and HSV (1/217), respectively. Rapid viral clearance was typical for HSV, VZV, CMV, and EV infections, although the maximum duration of viral detection was 15days for HSV and 12days for VZV, respectively. This suggests that the detection of HSV, VZV, CMV, and EV strongly indicates symptomatic viral CNS disease. Secondary viral reactivation mostly underlies positive EBV and HHV-6 findings. Their detection does not rule out clinical impact but recommends searching for additional underlying conditions.

Prevention and management of neonatal herpes simplex virus infections

Human herpes simplex virus (HSV) infection in neonates can result in devastating outcomes, including mortality and significant morbidity. All infants are potentially at risk for neonatal HSV infection. This position statement reviews epidemiology, transmission and risk factors, with a focus on intrapartum infection. It considers diagnosis and prognosis according to infection category, along with testing modalities and limitations. Recommendations for managing newborns known to have been exposed intrapartum to HSV are based on expert opinion because a randomized trial to compare management options is not feasible. Guidance is provided for the empirical management of infants with suspected clinical sepsis, including those who do not respond to antibacterial therapy. The present statement replaces a 2006 position statement by the Canadian Paediatric Society.

Detection of human herpesvirus 7 DNA from the CSF in association with neurosarcoidosis

This study reports a previously healthy, immunocompetent adult male in whom human herpesvirus 7 (HHV-7) DNA was detected continuously from the cerebrospinal fluid (CSF). This patient developed definite sarcoidosis with primary symptomatic manifestations in the central nervous system (CNS). The initial presentation was with loss of visual acuity and papilledema. Brain MR imaging at presentation confirmed papilledema, but otherwise there were no focal abnormalities or signs of hydrocephalus. CSF investigation revealed pleocytosis and elevated protein levels. HHV-7 DNA was detected repeatedly from CSF but not from blood over 1 year follow-up. High resolution computed tomography of lungs was normal. Positron emission tomography showed several metabolically active lymph nodes in the mediastinum, and the histopathological investigation revealed granulomatous inflammation consistent with sarcoidosis. The finding of HHV-7 DNA in the CSF in the context of neurosarcoidosis has not been reported previously. The detection of HHV-7 DNA may result from the selective activation of CD4+ T-lymphocytes in the CSF caused by neurosarcoidosis. Further studies are needed to establish whether the detection of HHV-7 DNA in the CSF in association with neurosarcoidosis represents a clinically significant HHV-7 CNS infection.

A miniaturized and integrated gel post platform for multiparameter PCR detection of herpes simplex viruses from raw genital swabs

Herpes simplex virus (HSV) is one of the most prevalent viruses, with acute and recurrent infections in humans. The current gold standard for the diagnosis of HSV is viral culture which takes 2-14 days and has low sensitivity. In contrast, DNA amplification by polymerase chain reaction (PCR) can be performed within 1-2 h. We here describe a multiparameter PCR assay to simultaneously detect HSV-1 and HSV-2 DNA templates, together with integrated positive and negative controls, with product detection by melting curve analysis (MCA), in an array of semi-solid polyacrylamide gel posts. Each gel post is 0.67 μL in volume, and polymerized with all the components required for PCR. Both PCR and MCA can currently be performed in one hour and 20 min. Unprocessed genital swabs collected in universal transport medium were directly added to the reagents before or after polymerization, diffusing from atop the gel posts. The gel post platform detects HSV templates in as little as 2.5 nL of raw sample. In this study, 45 genital swab specimens were tested blindly as a preliminary validation of this platform. The concordance of PCR on gel posts with conventional PCR was 91%. The primer sequestration method introduced here (wherein different primers are placed in different sets of posts) enables the simultaneous detection of multiple pathogens for the same sample, together with positive and negative controls, on a single chip. This platform accepts unprocessed samples and is readily adaptable to detection of multiple different pathogens or biomarkers for point-of-care diagnostics.

Evaluation of multiplex polymerase chain reaction and microarray-based assay for rapid herpesvirus diagnostics

Rapid diagnosis is critical to minimize morbidity and mortality associated with infections of the central nervous system (CNS). In this study, we evaluated the performance of a multiplex polymerase chain reaction (PCR) and microarray-based method, Prove-it™ Herpes, in a routine clinical laboratory setting for the diagnostics of 7 herpesviruses in viral CNS infections. Cerebrospinal fluid samples (n = 495), which had arrived for diagnostics in the 5 participating laboratories, were analyzed for herpesvirus DNA both by the current PCR-based method of the laboratory and by the microarray assay. The sensitivity and specificity for the microarray assay were 93% and 99%, respectively. The microarray assay was considered as a rapid and robust diagnostic platform that was easily implemented into the laboratory workflow. The broad herpesvirus coverage and the small sample volume required by the assay could benefit the diagnostics and thus the treatment of life-threatening infections of the CNS, especially among immunocompromised patients.

Rapid virological diagnosis of central nervous system infections by use of a multiplex reverse transcription-PCR DNA microarray

Viruses are the main etiological cause of central nervous system (CNS) infections. A rapid molecular diagnosis is recommended to improve the therapeutic management of patients. The aim of this study was to evaluate the performances of a DNA microarray, the Clart Entherpex kit (Genomica, Coslada, Spain), allowing the rapid and simultaneous detection of 9 DNA and RNA neurotropic viruses: herpes simplex virus 1 (HSV-1), HSV-2, varicella-zoster virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), HHV-7, HHV-8, and the human enteroviruses (HEVs). This evaluation was performed with 28 samples from the European proficiency panels (Quality Control for Molecular Diagnostics [QCMD]; Glasgow, Scotland) and then with 78 cerebrospinal fluid (CSF) specimens. The majority of the QCMD results obtained by the DNA microarray were similar to those recorded by the overall QCMD participants. The main discrepant results were observed for low concentrations of HSV-2 and HEVs. From the clinical samples, the kit detected 27 of the 28 herpesvirus CNS infections and all of the 30 HEV-positive CSF samples. No false-positive result was observed among the 20 virus-negative CSF samples. The clinical sensitivity, specificity, and negative and positive predictive values of the assay were 98.3, 100, 95.2, and 100%, respectively, when the results were compared to those of commercially available PCR assays. Interestingly, HHV-7 was detected in 11 (37%) of the 30 HEV-positive CSF samples from children suffering from aseptic meningitis causing significantly longer lengths of stay at the hospital than infection with HEVs alone (2.4 versus 1.4 days; P = 0.038). In conclusion, this preliminary study showed that this DNA microarray could be a valuable molecular diagnostic tool for single and mixed DNA and RNA virus infections of the CNS.

A novel real-time PCR system for simultaneous detection of human viruses in clinical samples from patients with uncertain diagnoses

A novel simultaneous detection system for human viruses was developed using a real‐time polymerase chain reaction (PCR) system to identify causes of infection in clinical samples from patients with uncertain diagnoses. This system, designated as the “multivirus real‐time PCR,” has the potential to detect 163 human viruses (47 DNA viruses and 116 RNA viruses) in a 96‐well plate simultaneously. The specificity and sensitivity of each probe–primer set were confirmed with cells or tissues infected with specific viruses. The multivirus real‐time PCR system showed profiles of virus infection in 20 autopsies of acquired immunodeficiency syndrome patients, and detected frequently TT virus, cytomegalovirus, human herpesvirus 6, and Epstein–Barr virus in various organs; however, RNA viruses were detected rarely except for human immunodeficiency virus‐1. Pathology samples from 40 patients with uncertain diagnoses were examined, including cases of encephalitis, hepatitis, and myocarditis. Herpes simplex virus 1, human herpesvirus 6, and parechovirus 3 were identified as causes of diseases in four cases of encephalitis, while no viruses were identified in other cases as causing disease. This multivirus real‐time PCR system can be useful for detecting virus in specimens from patients with uncertain diagnoses. J. Med. Virol. 83:322–330, 2011. © 2010 Wiley‐Liss, Inc.

Single tube multiplex real-time PCR for the rapid detection of herpesvirus infections of the central nervous system

Human herpesvirus infection of immunocompromised hosts may lead to central nervous system (CNS) infection and diseases. In this study, a single tube multiplex real-time PCR was developed for the detection of five herpesviruses (HSV-1, HSV-2, VZV, EBV and CMV) in clinical cerebrospinal fluid (CSF) specimens. Two primer pairs specific for the herpesvirus polymerase gene and five hybridization probe pairs for the specific identification of the herpesvirus types were used in a LightCycler multiplex real-time PCR. A singleplex real-time PCR was first optimized and then applied to the multiplex real-time PCR. The singleplex and multiplex real-time PCRs showed no cross-reactivity. The sensitivity of the singleplex real-time PCR was 1 copy per reaction for each herpesvirus, while that of the multiplex real-time PCR was 1 copy per reaction for HSV-1 and VZV and 10 copies per reaction for HSV-2, EBV and CMV. Intra and inter-assay variations of the single tube multiplex assay were in the range of 0.02%-3.67% and 0.79%-4.35%, respectively. The assay was evaluated by testing 62 clinical CSF samples and was found to have equivalent sensitivity, specificity and agreement as the routine real-time PCR, but reducing time, cost and amount of used sample.

Comparison of the levels of human herpesvirus 6 (HHV-6) DNA and cytokines in the cerebrospinal fluid and serum of children with HHV-6 encephalopathy

Primary human herpesvirus-6 (HHV-6) infection is a common cause of acute sporadic encephalopathy in Japanese children. Occasionally, HHV-6 is not detected in the cerebrospinal fluid (CSF) of patients with encephalopathy, for example, in those with focal viral encephalitis, such as herpes simplex viral encephalitis. This indicates that HHV-6 encephalopathy is caused by an indirect mechanism, although this is not fully understood. HHV-6 DNA, cytokines (interleukin (IL)-1beta, IL-6, IL-8, IL-10, IL-12 p70, tumor necrosis factor-alpha, interferon-gamma), and matrix metalloproteinase-9 were quantitated in both the CSF and serum of 13 patients with HHV-6 encephalopathy during the acute phase of the disease. HHV-6 DNA was detected in the CSF of seven patients with HHV-6 encephalopathy. The viral DNA concentration was significantly higher in serum than in CSF (mean 1.64 x 10(4) vs. 5.70 x 10(1) copies/ml; P = 0.003). The lack or low level of viral DNA in the CSF samples suggests that direct invasion of the central nervous system by HHV-6 is not the main cause of encephalopathy. Additionally, the IL-10 concentration was significantly higher in serum than in CSF (P < 0.001), whereas there was no significant difference in IL-6 levels between the CSF and serum samples. Interestingly, the IL-8 concentration was significantly higher in CSF than in serum (P = 0.038). The distribution of these cytokines differed between CSF and serum. The high CSF concentration of IL-8 could play an important role in the pathogenesis of encephalopathy.

Advances in pediatric neurovirology

Viral infections of the pediatric central nervous system (CNS) encompass a broad spectrum of both perinatally and postnatally acquired diseases with potentially devastating effects on the developing brain. In children, viral infections have been associated with chronic encephalopathy, encephalitis, demyelinating disease, tumors, and epilepsy. Older diagnostic techniques of biopsy, viral culture, electron microscopy, gel-based polymerase chain reaction (PCR), and viral titer quantification are being replaced with more rapid, sensitive, and specific real-time and microarray-based PCR technologies. Advances in neuroimaging technologies have provided for earlier recognition of CNS injury without elucidation of specific viral etiology. Although the mainstay therapy of many pediatric neurovirologic diseases, aside from HIV, includes intravenous acyclovir, much work is being done to develop novel antiviral immunotherapies aimed at both treating and preventing pediatric CNS viral disease.

Multiplex real-time PCR assay for simultaneous quantification of BK polyomavirus, JC polyomavirus, and adenovirus DNA

In recent years, virus-induced nephropathy caused mainly by BK polyomavirus (BKPyV), JC polyomavirus (JCPyV), and adenovirus has emerged as a problem in renal transplant patients. In the present study, we developed a multiplex real-time PCR assay to quantify the viral load of BKPyV, JCPyV, and adenovirus simultaneously. The dynamic range covered at least 6 orders of magnitude. This system was specific and reproducible, even in the presence of large amounts of DNA of other viruses. To validate this assay, urine samples from 124 renal transplant patients and serum samples from 18 hemorrhagic cystitis patients after hematopoietic stem cell transplantation were examined. In the urine samples from renal transplant patients, BKPyV was detected in 28 patients (22.6%), JCPyV was detected in 51 patients (41.1%), and adenovirus was detected in 2 patients (1.6%). The maximum amounts of each virus detected were 2.7 x 10(9), 8.7 x 10(8), and 1.2 x 10(2) copies/ml, respectively. Decoy cells were observed in 31 patients. The quantities of both BKPyV and JCPyV DNA were greater in samples with decoy cells. Two patients whose BKPyV viral loads exceeded 10(8) copies/ml had elevated serum creatinine levels and were diagnosed with BKPyV nephropathy based on graft biopsies. In serum samples from hemorrhagic cystitis patients, BKPyV, JCPyV, and adenovirus was detected in six, two, and three patients, respectively. Strong correlations were observed between the viral DNA copy numbers determined in the multiplex assays and those determined in single assays. Since this new assay is rapid, sensitive, and specific, it can be used for quantitative analyses of viruses in urine and serum samples after transplantation.

Aging promotes neutrophil-induced mortality by augmenting IL-17 production during viral infection

Morbidity and mortality associated with viral infections increase with age, although the underlying mechanisms are unclear. Here, we investigated whether aging alters inflammatory responses during systemic viral infection and thereby contributes to virus-induced death. We found that infection of aged mice with systemic herpes viruses led to rapid increases in serum IL-17, neutrophil activation, and mortality due to hepatocyte necrosis. In contrast, all young mice survived infection, displaying weaker IL-17 induction and neutrophil activation. Natural killer T (NKT) cells isolated from the livers of aged mice produced more IL-17 than did young cells, and adoptively transferred aged NKT cells induced liver injury in young mice impaired in viral control. Importantly, IL-17 neutralization or neutrophil depletion during viral infection reduced liver damage and prevented death of aged mice. These results demonstrate that, during systemic viral infection, aging alters the host-pathogen interaction to overproduce IL-17, contributing to liver injury and death.