Detection and typing of human herpesvirus 6 by molecular methods in specimens from patients diagnosed with encephalitis or meningitis

The Association of HHV-6 and the TNF-α (-308G/A) Promotor with Major Depressive Disorder Patients and Healthy Controls in Thailand

Major depressive disorder (MDD) is a silent global health problem that can lead to suicide. MDD development is suggested to result from numerous risk factors, including genetic factors. A precise tool for MDD diagnosis is currently not available. Recently, inflammatory processes have been identified as being strongly involved in MDD development and the reactivation of human herpesvirus type 6 (HHV-6), upregulating cytokines such as TNF-α, which are associated with MDD. Therefore, this study aimed to determine the association of HHV-6 with genetic factors, especially TNF-α mutation, in MDD patients and their relatives compared to healthy controls. The Patient Health Questionnaire (PHQ-9) was used to evaluate MDD status, and 471 oral buccal samples were investigated for HHV-6 infection and viral copy number by qPCR. TNF-α (-308G/A) gene mutation and the cytokines TNF-α, IL-6, and IL-10 were analyzed by high-resolution melting (HRM) analysis and enzyme-linked immunosorbent assay (ELISA). Whole-exome sequencing of buccal samples was performed to analyze for genetic factors. The results showed significantly higher HHV-6 positivities and viral loads in MDD patients (15/59 (25.67%) and 14,473 ± 16,948 copies/µL DNA) and their relatives (blood relatives 17/36 (47.22%) and 8146 ± 5656 copies/µL DNA); non-blood relatives 7/16 (43.75%) and 20,721 ± 12,458 copies/µL DNA) compared to the healthy population (51/360 (14.17%) and 6303 ± 5791 copies/µL DNA). The TNF-α (-308G/A) mutation showed no significant difference. Surprisingly, 12/26 (46.15%) participants with the TNF-α (-308G/A) mutation showed HHV-6 positivities at higher rates than those with wild-type TNF-α (-308G) (70/267 (26.22%)). HHV-6-positive participants with TNF-α (-308G/A) showed higher levels of TNF-α, IL-6, and IL-10 than those of negative control. Exome analysis revealed that common mutations in immune genes were associated with depression. Therefore, this study unveiled the novel association of inflammatory gene TNF-α (-308G/A) mutations with HHV-6 reactivation, which could represent a combined risk factor for MDD. This result could induce further research on MDD development and clinical applications.

Human herpes virus type-6 is associated with central nervous system infections in children in Sudan

Background

Human herpes virus type-6 (HHV-6) is increasingly recognised as a febrile agent in children. However, less is known in sub-Saharan African countries, including Sudan.

Objective

We investigated the involvement of HHV-6 in paediatric central nervous system (CNS) infections in Khartoum, Sudan.

Methods

Febrile patients aged up to 15 years with suspected CNS infections at Omdurman Hospital for Children from 01 December 2009 to 01 August 2010 were included. Viral DNA was extracted from leftover cerebrospinal fluid (CSF) specimens and quantitatively amplified by real-time polymerase chain reaction (PCR) at Umeå University in Sweden.

Results

Of 503 CSF specimens, 13 (2.6%) were positive for HHV-6 (33.0% [13/40 of cases with proven infectious meningitis]). The median thermal cycle threshold for all HHV-6-positive specimens was 38 (range: 31.9–40.8). The median number of virus copies was 281.3/PCR run (1 × 10⁵ copies/mL CSF; range: 30–44 × 10³ copies/PCR run [12 × 10³ – 18 × 10⁶ copies/mL CSF]). All positive patients presented with fever and vomiting; 86.0% had seizures. The male-to-female ratio was 1:1; 50.0% were toddlers, 42.0% infants and 8.0% teenagers. Most (83.0%) were admitted in the dry season and 17.0% in the rainy season. Cerebrospinal fluid leukocytosis was seen in 33.0%, CSF glucose levels were normal in 86.0% and low in 14.0%, and CSF protein levels were low in 14.0% and high in 43.0%.

Conclusion

Among children in Sudan with CNS infections, HHV-6 is common. Studies on the existence and spread of HHV-6 chromosomal integration in this population are needed.

Incidental Detection of Human Herpesvirus-6 in Cerebrospinal Fluid Analysis: To Treat or Not to Treat?

Human herpesvirus-6 (HHV-6) is a ubiquitous beta herpes virus which can result in meningitis/ meningoencephalitis in humans. FilmArray meningitis/encephalitis panel (BioFire Diagnostics, Salt Lake City, UT) is employed in medical centers for the establishment of a central nervous system (CNS) infection, and HHV-6 is often positive. However, establishing HHV-6 as a cause of meningitis or encephalitis is difficult at the present time, as a polymerase chain reaction (PCR) test alone does not establish the etiology of the CNS infection. HHV-6 can be transmitted in a Mendelian fashion by integrating into the human genome (ciHHV-6 or chromosomally integrated HHV-6). We present a case of a 34-week gestational age neonate in the neonatal intensive care unit (NICU) who tested positive for HHV-6 through a panel screening, presumably due to ciHHV-6 infection. Knowledge and understanding of this phenomenon is essential in preventing misdiagnosis of active HHV-6 infection and subsequent unnecessary antiviral treatment.

Central Nervous System Complications due to Human Herpesvirus 6 Infection in Pediatric Age Group

Human herpesvirus 6 (HHV-6) has been demonstrated to be a neurotropic virus and has been linked to several neurological complications associated with a wide range of clinical outcomes. Here, we present data from immunocompetent children with a central neurological condition and intrathecal DNA detection of HHV-6 virus. Through these cases, physiopathology, investigations, and outcome of the disease will be described. Finally, specific treatment will be discussed.

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.

Human Herpesvirus-6 may be Neurologically Injurious in Some Immunocompetent Children

PURPOSE

Human herpesvirus 6 (HHV-6) can infect the central nervous system in immunocompromised individuals. Less is known, however, about HHV-6 infection in immunocompetent patients. This study evaluated the neurologic features and prognosis of HHV-6 infection in immunocompetent patients.

METHODS

The medical records of patients aged 1 month to 18 years who underwent cerebrospinal fluid examinations and were tested for 6 viruses, including HHV-6, by multiplex polymerase chain reaction were evaluated retrospectively.

RESULTS

During the study period, 252 children were included. None had underlying disease and all were immunocompetent. Their mean age at diagnosis was 40.98 ± 47.65 months. Of these 252 patients, 144 (57.1%) were diagnosed with meningitis, 84 (33.3%) with febrile seizure not induced by meningitis, and 24 (9.5%) with encephalitis. Of the 9 patients positive for HHV-6, 3 (33.3%) had encephalitis, 3 (33.3%) had meningitis, 1 (11.1%) had complex febrile seizure, and the other 2 patients had fever alone. Outcomes were worse in the seizure group (Fisher exact test, P = .048), especially in patients with status epilepticus (Fisher exact test, P = .012), than in the other groups. Encephalitis patients with and without HHV-6 differed significantly in age (24.0 ± 10.8 vs 63.4 ± 47.7 months, t-test P < .05), with status epilepticus being more frequent in those with HHV-6 (Fisher exact test, P = .010). All 3 encephalitis patients positive for HHV-6 had neurologic sequelae; 2 who had mild sequelae were treated with antiviral agents and intravenous immunoglobulin.

CONCLUSIONS

HHV-6 may not be completely benign in immunocompetent children. It can be associated with encephalitis and poor prognosis.

Human herpes virus 6 reactivation following autologous hematopoietic cell transplantation - a single-center experience

Data regarding presentation and management of human herpes virus 6 (HHV-6) reactivation among autologous hematopoietic cell transplantation (HCT) recipients are limited. We retrospectively reviewed medical charts of all autologous HCT patients tested for HHV-6 reactivation due to suspected clinical presentation between 1/2012 and 8/2017. Among 328 autologous HCT recipients, 44 patients were tested for HHV-6 reactivation. Thirty patients tested positive; 29 (97%) had sustained fever, six (20%) had rash and four (13%) had pneumonia. Median C-reactive protein was significantly lower in HHV-6 positive patients compared to negative patients (3.6 (range, 0.4-11) vs. 9.6 (range, 3.2-30) mg/dL, respectively, p = .004). Ganciclovir formulations were administrated in 29 (97%) patients with median time to fever resolution of one (range, 1-2) day. HHV-6 should be considered as an important cause of post engraftment fever in autologous HCT. Larger studies are warranted to evaluate incidence of HHV-6 reactivation and optimal treatment regimen.

Clarifying Indeterminate Results on the Rabies Direct Fluorescent Antibody Test Using Real-Time Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVES

Each year, rabies virus infection results in the death of more than 50 000 persons worldwide. In the United States, the Centers for Disease Control and Prevention (CDC) reported 23 human rabies cases from May 1, 2008, through October 1, 2017. Although rabies testing in the United States is highly reliable, some specimens submitted to rabies laboratories do not have adequate tissues or may be substantially decomposed. In these instances, the specimen may be considered unsatisfactory for testing or produce indeterminate results using the gold standard direct fluorescent antibody test. The objective of this study was to evaluate the number of unsatisfactory samples or samples with indeterminate results that were positive for rabies virus after additional testing using real-time reverse transcriptase polymerase chain reaction (RT-PCR).

METHODS

In 2016, we retested all unsatisfactory specimens or specimens with indeterminate results using real-time RT-PCR. We further typed any sample that was real-time RT-PCR positive to identify the infecting rabies virus variant.

RESULTS

Of 210 retested unsatisfactory specimens or specimens with indeterminate results, 9 (4.3%) were positive for rabies. In each case, the animal was infected with a homologous rabies virus variant.

CONCLUSION

These results confirm the recommendation by CDC and state public health laboratories that indeterminate results should be considered positive and justify the prompt treatment of exposed persons through an animal that is suspected to have rabies.

Primary infection with human herpes virus type 6, post-pediatric liver transplantation-A pathogen to remember

BACKGROUND

In recent years, liver transplantation (LT) has become a well-accepted therapeutic modality for children with end-stage liver disease, with transplantation surgery being performed at a younger age. Human herpes virus 6 (HHV-6) infection occurs in most children within the first 2 years of life, therefore, data on primary HHV-6 infection in pediatric liver transplant recipients is scarce.

OBJECTIVE

To describe the course of primary HHV-6 infection after pediatric LT.

METHODS

Medical files, between the years 2015-2016, of post-LT pediatric patients with suspected primary HHV-6 infection were reviewed. Clinical and laboratory data for enrolled cases were evaluated. Primary infection was defined as DNAemia in children who were seronegative prior to transplantation or seroconversion from negative to positive IgG posttransplantation.

RESULTS

Four cases of primary HHV-6 (type B) infection were identified among the 26 children who had undergone LT at our center during the study period. All patients were <1 year old and presented with fever, hepatitis, and elevated inflammatory markers, most (75%) within a short-period posttransplantation. All were initially treated with empiric antibiotics for a suspected bacterial infection and three underwent liver biopsy, one showing signs of rejection. Three were treated with antiviral therapy with a gradual resolution of symptoms.

DISCUSSION

Primary HHV-6 should be taken into account in young children shortly after LT, especially when presenting with fever and elevated liver enzymes. Treatment with antiviral therapy should be considered.

CONCLUSIONS

In young infants post-LT, a high index of suspicion may promote early detection of HHV-6 primary infection and prevent serious complications.

Chemokines encoded by herpesviruses

Viruses use diverse strategies to elude the immune system, including copying and repurposing host cytokine and cytokine receptor genes. For herpesviruses, the chemokine system of chemotactic cytokines and receptors is a common source of copied genes. Here, we review the current state of knowledge about herpesvirus-encoded chemokines and discuss their possible roles in viral pathogenesis, as well as their clinical potential as novel anti-inflammatory agents or targets for new antiviral strategies.

Successful treatment and FDG-PET/CT monitoring of HHV-6 encephalitis in a non-neutropenic patient: case report and literature review

Human herpesvirus (HHV)-6 reactivation is associated with severe forms of encephalitis among patients undergoing hematopoietic stem cell transplantation. Cases in non-neutropenic patients are uncommon. The efficacy of ganciclovir and other compounds that are used for the treatment of HHV-6 encephalitis remains suboptimal and linked to toxicity. Valganciclovir, the oral prodrug of ganciclovir, could be practical to treat outpatients, but it is not commonly used for severe cases. We report a case of HHV-6 encephalitis in a non-neutropenic patient successfully treated with valganciclovir and undergoing therapeutic drug monitoring in plasma and in the cerebrospinal fluid. Resolution of infectious foci was documented by cerebral MRI and F18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT). A review of the literature on HHV-6 encephalitis is also reported.

The spectrum of aseptic central nervous system infections in southern Germany - demographic, clinical and laboratory findings

BACKGROUND AND PURPOSE

Aseptic infections of the central nervous system (CNS) are frequently observed in Germany. However, no study has systematically addressed the spectrum of aseptic CNS infections in Germany.

METHODS

Data on 191 adult patients diagnosed from January 2007 to December 2014 with aseptic meningitis or encephalitis/meningoencephalitis at our hospital were collected by chart review and analyzed for demographic, clinical and laboratory findings. Patients were stratified according to the causative virus and findings were compared between groups.

RESULTS

In our cohort, meningitis was caused in 36% by enterovirus (EV), 15% by herpes simplex virus (HSV), 12% by varicella zoster virus (VZV) and 5% by tick borne encephalitis (TBE). Encephalitis/meningoencephalitis was caused in 13% by HSV, 13% by VZV, and three out of 11 tested patients were positive for TBE. The highest incidence of EV infections was between 25 and 35 years and of HSV infections between 30 and 60 years. VZV infections had a bimodal distribution peaking below 30 and above 70 years. VZV and EV infections were more frequently observed during summer, whereas HSV infections showed no seasonal preference. Inflammatory changes in cerebrospinal fluid (CSF) were highest in HSV and lowest in EV infections.

CONCLUSIONS

Polymerase chain reaction tests for HSV, VZV and EV in CSF and TBE serology determined the causative virus in over 60% of tested patients. The age of affected patients, seasonal distribution, disease course and inflammatory changes in CSF differ between groups of patients affected by the most common viral infections.

Comparative evaluation of a laboratory developed real-time PCR assay and the RealStar® HHV-6 PCR Kit for quantitative detection of human herpesvirus 6

BACKGROUND

HHV-6 reactivation in immunocompromised patients is common and may be associated with serious morbidity and mortality; therefore, early detection and initiation of therapy might be of benefit. Real-time PCR assays allow for early identification of HHV-6 reactivation to assist in providing a timely response. Thus, we compared the performance of an in-house developed HHV-6 quantitative PCR assay with a commercially available kit, the RealStar^® HHV-6 PCR Kit.

METHOD

The analytical sensitivity, analytical specificity, linearity, precision and accuracy of the in-house developed HHV-6 qPCR assay were evaluated. The diagnostic performance of the in-house HHV-6 qPCR assay was compared with the RealStar^® HHV-6 PCR Kit, using 72 clinical specimens and 17 proficiency testing samples.

RESULTS

Linear regression analysis of the quantitative results showed a dynamic range from 2 to 10 log₁₀ copies/ml and a coefficient of determination (R²) of 0.999 for the in-house assay. A dilution series demonstrated a limit of detection and a limit of quantification of 1.7 log₁₀ and 2 log₁₀ copies/ml, respectively. The precision of the assay was highly reproducible among runs with coefficients of variance (CV) ranging from 0.27% to 4.37%. A comparison of 27 matched samples showed an excellent correlation between the quantitative viral loads measured by the in-house HHV-6 qPCR assay and the RealStar^® HHV-6 PCR Kit (R²=0.926; P<0.0001), with an average bias of -0.24 log₁₀ copies/ml.

CONCLUSIONS

The in-house developed HHV-6 qPCR method is a sensitive and reliable assay with lower cost for the detection and quantification of HHV-6 DNA when compared to the RealStar^® HHV-6 PCR Kit.

Zika Virus Testing Considerations: Lessons Learned from the First 80 Real-Time Reverse Transcription-PCR-Positive Cases Diagnosed in New York State

The performance and interpretation of laboratory tests for Zika virus (ZKV) continue to be evaluated. Serology is cross-reactive, laborious, and frequently difficult to interpret, and serum was initially solely recommended for molecular diagnosis. ZKV testing was initiated in January 2016 in New York State for symptomatic patients, pregnant women, their infants, and patients with Guillain-Barré syndrome who had traveled to areas with ZKV transmission. Subsequently, eligibility was expanded to pregnant women with sexual partners with similar travel histories. Serum and urine collected within 4 weeks of symptom onset or within 6 weeks of travel were tested with real-time reverse transcription-PCR (RT-PCR) assays targeting the ZKV envelope and NS2B genes. In this review of lessons learned from the first 80 positive cases in NYS, ZKV RNA was detected in urine only in 50 patients, in serum only in 19 patients, and in both samples concurrently in 11 patients, with average viral loads in urine a log higher than those in serum. Among 93 positive samples from the 80 patients, 41 were positive on both gene assays, 52 were positive on the envelope only, and none were positive on the NS2B only. Of the 80 infected patients, test results for 74 (93%) would have defined their infection status as not detected or equivocal if the requirement for positive results from two assay targets (two-target-positive requirement) in the initial federal guidance to public health laboratories was enforced, if urine was not tested, or if the extended eligibility time for molecular testing was not implemented. These changes facilitated more extensive molecular diagnosis of ZKV, reducing reliance on time-consuming and potentially inconclusive serology.

Comparison of Automated Quantitative Reverse Transcription-PCR and Direct Fluorescent-Antibody Detection for Routine Rabies Diagnosis in the United States

Rabies virus found worldwide and prevalent throughout the United States continues to be a public health concern. Direct-fluorescent antibody (DFA) detection remains the gold standard for rabies virus diagnostics. Assessing the utility of a high-throughput molecular platform such as the QIAsymphony SP/AS, in conjunction with quantitative reverse transcription-PCR (qRT-PCR), to augment or potentially replace the DFA test, was the focus of this project. Here we describe a triplex qRT-PCR assay, including assembly and evaluation for sensitivity, specificity, and ability to detect variants. Additionally, we compared the qRT-PCR assay to the gold standard direct fluorescent-antibody test. More than 1,000 specimens submitted for routine rabies diagnosis were tested to directly compare the two methods. All results were in agreement between the two methods, with one additional specimen detected by qRT-PCR below the limits of the DFA sensitivity. With the proper continued validation for variant detection, molecular methods have a place in routine rabies diagnostics within the United States.

The Putative Role of Viruses, Bacteria, and Chronic Fungal Biotoxin Exposure in the Genesis of Intractable Fatigue Accompanied by Cognitive and Physical Disability

Patients who present with severe intractable apparently idiopathic fatigue accompanied by profound physical and or cognitive disability present a significant therapeutic challenge. The effect of psychological counseling is limited, with significant but very slight improvements in psychometric measures of fatigue and disability but no improvement on scientific measures of physical impairment compared to controls. Similarly, exercise regimes either produce significant, but practically unimportant, benefit or provoke symptom exacerbation. Many such patients are afforded the exclusionary, non-specific diagnosis of chronic fatigue syndrome if rudimentary testing fails to discover the cause of their symptoms. More sophisticated investigations often reveal the presence of a range of pathogens capable of establishing life-long infections with sophisticated immune evasion strategies, including Parvoviruses, HHV6, variants of Epstein-Barr, Cytomegalovirus, Mycoplasma, and Borrelia burgdorferi. Other patients have a history of chronic fungal or other biotoxin exposure. Herein, we explain the epigenetic factors that may render such individuals susceptible to the chronic pathology induced by such agents, how such agents induce pathology, and, indeed, how such pathology can persist and even amplify even when infections have cleared or when biotoxin exposure has ceased. The presence of active, reactivated, or even latent Herpes virus could be a potential source of intractable fatigue accompanied by profound physical and or cognitive disability in some patients, and the same may be true of persistent Parvovirus B12 and mycoplasma infection. A history of chronic mold exposure is a feasible explanation for such symptoms, as is the presence of B. burgdorferi. The complex tropism, life cycles, genetic variability, and low titer of many of these pathogens makes their detection in blood a challenge. Examination of lymphoid tissue or CSF in such circumstances may be warranted.

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.

Germ-line transmitted, chromosomally integrated HHV-6 and classical Hodgkin lymphoma

A unique feature of both human herpesvirus 6A and B (HHV-6A and B) among human herpesviruses is their ability to integrate into chromosomal telomeres. In some individuals integrated viral genomes are present in the germ-line and result in the vertical transmission of HHV-6; however, little is known about the disease associations of germ-line transmitted, chromosomally integrated HHV-6 (ciHHV-6). Recent publications suggest that HHV-6 is associated with classical Hodgkin lymphoma (cHL). Here we examine the prevalence of ciHHV-6 in 936 cases of cHL and 563 controls by screening with a duplex TaqMan assay and confirming with droplet digital PCR. ciHHV-6 was detected in 10/563 (1.8%) controls and in all but one individual the virus was HHV-6B. Amongst cases 16/936 (1.7%) harboured ciHHV-6, thus demonstrating no association between ciHHV-6 and risk of cHL.

Epidemiology of herpes human virus 6 and 7 infections in salivary gland neoplasms in isfahan, iran

Background:

The previous studies showed that herpes human virus-6 (HHV-6) and HHV-7 exist in salivary glands. One of the important areas in oral and maxillofacial pathology field is tumors of the salivary glands. In this study, to declare the major sites of persistent infection with HHV-6 and HHV-7, the existence of HHV-6 and HHV-7 genomes in formalin-fixed paraffin embedded tissue samples of salivary gland tumors.

Methods:

This analytical study was performed in 60 paraffin blocks samples of malignant and benign neoplasms of both major and minor salivary glands. This study performed with highly sensitive real time PCR method.

Results:

Among 60 paraffin blocks salivary gland tumors with equal chances of presence of the HHV-7 and HHV-6 in the samples, 34% were positive for both HHV-7 and HHV-6 while 47.2% were only positive for HHV-7, 18.9% samples were positive for HHV-6. A relationship was noticed between HHV-7 and HHV-6 genomes.

Conclusion:

In conclusion, this study showed no relation between virus and diseases with P=0.953. Also it could be inferred that there is a relationship between HHV-6 and 7 in salivary glands neoplasms.

Prevalence of HHV-6 in cerebrospinal fluid of children younger than 2 years of age with febrile convulsion

BACKGROUND AND OBJECTIVE

Febrile convulsion is a common disorder in children. Viral infections such as human herpes virus 6 (HHV-6) which results in roseola infantum may contribute to developing seizure. The objective of this study was to determine the prevalence of HHV-6 by detecting DNA in cerebrospinal fluid (CSF) of children with febrile convulsion and without any rash of roseola infantum.

MATERIALS AND METHODS

In this descriptive cross-sectional study, CSF of 100 children younger than 2 years of age with febrile convulsion was evaluated for detecting HHV-6 DNA by PCR. All of them were referred to emergency ward in Pediatric Medical Center from March 2010 to March 2011. General information, clinical manifestations, laboratory tests and outcomes were collected in the questionnaires.

RESULTS

One hundred children including 59 males and 41 females were evaluated. HHV-6 was detected from CSF in six patients (6%) by PCR. Mean age was 8 months old. All children were younger than 12 months old. The most common primary manifestation was fever alone. None of them had rash. Majority of cases occurred in winter. All patients recovered without any encephalitis.

CONCLUSION

These findings showed that primary infection with HHV-6 is frequently associated with febrile convulsion in infants which may be at risk for subsequent development of epilepsy.

Human Herpesvirus 6 and Neuroinflammation

Human herpesvirus (HHV-) 6A and HHV-6B are two distinct β-herpesviruses which have been associated with various neurological diseases, including encephalitis, meningitis, epilepsy, and multiple sclerosis. Although the reactivation of both viruses is recognized as the cause of some neurological complications in conditions of immunosuppression, their involvement in neuroinflammatory diseases in immunocompetent people is still unclear, and the mechanisms involved have not been completely elucidated. Here, we review the available data providing evidence for the capacity of HHV-6A and -6B to infect the central nervous system and to induce proinflammatory responses by infected cells. We discuss the potential role of both viruses in neuroinflammatory pathologies and the mechanisms which could explain virus-induced neuropathogenesis.

Novel marmoset (Callithrix jacchus) model of human Herpesvirus 6A and 6B infections: immunologic, virologic and radiologic characterization

Human Herpesvirus 6 (HHV-6) is a ubiquitous virus with an estimated seroprevalence of 95% in the adult population. HHV-6 is associated with several neurologic disorders, including multiple sclerosis, an inflammatory demyelinating disease affecting the CNS. Animal models of HHV-6 infection would help clarify its role in human disease but have been slow to develop because rodents lack CD46, the receptor for cellular entry. Therefore, we investigated the effects of HHV-6 infections in a non-human primate, the common marmoset Callithrix jacchus. We inoculated a total of 12 marmosets with HHV-6A and HHV-6B intravenously and HHV-6A intranasally. Animals were monitored for 25 weeks post-inoculation clinically, immunologically and by MRI. Marmosets inoculated with HHV-6A intravenously exhibited neurologic symptoms and generated virus-specific antibody responses, while those inoculated intravenously with HHV-6B were asymptomatic and generated comparatively lower antibody responses. Viral DNA was detected at a low frequency in paraffin-embedded CNS tissue of a subset of marmosets inoculated with HHV-6A and HHV-6B intravenously. When different routes of HHV-6A inoculation were compared, intravenous inoculation resulted in virus-specific antibody responses and infrequent detection of viral DNA in the periphery, while intranasal inoculation resulted in negligible virus-specific antibody responses and frequent detection of viral DNA in the periphery. Moreover, marmosets inoculated with HHV-6A intravenously exhibited neurologic symptoms, while marmosets inoculated with HHV-6A intranasally were asymptomatic. We demonstrate that a marmoset model of HHV-6 infection can serve to further define the contribution of this ubiquitous virus to human neurologic disorders.

New rising infection: human herpesvirus 6 is frequent in myeloma patients undergoing autologous stem cell transplantation after induction therapy with bortezomib

Herpesvirus 6 (HHV-6) infection is a common complication during immunosuppression. Its significance for multiple myeloma (MM) patients undergoing autologous stem cell transplantation (ASCT) after treatment with novel agents affecting immune system remains undetermined. Data on 62 consecutive MM patients receiving bortezomib-dexamethasone (VD) (n = 41; 66%) or thalidomide-dexamethasone (TD) (n = 21, 34%) induction, together with melphalan 200 mg/m² autograft between 01.2005 and 09.2010, were reviewed. HHV-6 reactivation was diagnosed in patients experiencing postengraftment unexplained fever (PEUF) in the presence of any level of HHHV-6 DNA in blood. There were no statistically significant differences in patient characteristics between the groups, excluding dexamethasone dosage, which was significantly higher in patients receiving TD. Eight patients in TD and 18 in VD cohorts underwent viral screening for PEUF. HHV-6 reactivation was diagnosed in 10 patients of the entire series (16%), accounting for 35% of those screened; its incidence was 19.5% (n = 8) in the VD group versus 9.5% (n = 2) in the TD group. All patients recovered without sequelae. In conclusion, HHV-6 reactivation is relatively common after ASCT, accounting for at least a third of PEUF episodes. Further studies are warranted to investigate whether bortezomib has an impact on HHV-6 reactivation development.

No serological evidence for a role of HHV-6 infection in chronic fatigue syndrome

Human herpesvirus 6A (HHV-6A) and human herpesvirus 6B (HHV-6B) are associated with a variety of conditions including rash, fever, and encephalitis and may play a role in several neurological diseases. Here luciferase immunoprecipitation systems (LIPS) was used to develop HHV-6 serologic diagnostic tests using antigens encoded by the U11 gene from HHV-6A (p100) and HHV-6B (p101). Analysis of the antibody responses against Renilla luciferase fusions with different HHV-6B p101 fragments identified an antigenic fragment (amino acids 389 to 858) that demonstrated ~86% seropositivity in serum samples from healthy US blood donors. Additional experiments detected a HHV-6A antigenic fragment (amino acids 751-870) that showed ~48% antibody seropositivity in samples from Mali, Africa, a known HHV-6A endemic region. In contrast to the high levels of HHV-6A immunoreactivity seen in the African samples, testing of US blood donors with the HHV-6A p100 antigenic fragment revealed little immunoreactivity. To potentially explore the role of HHV-6 infection in human disease, a blinded cohort of controls (n=59) and chronic fatigue syndrome (CFS) patients (n=72) from the US was examined for serum antibodies. While only a few of the controls and CFS patients showed high level immunoreactivity with HHV-6A, a majority of both the controls and CFS patients showed significant immunoreactivity with HHV-6B. However, no statistically significant differences in antibody levels or frequency of HHV-6A or HHV-6B infection were detected between the controls and CFS patients. These findings highlight the utility of LIPS for exploring the seroepidemiology of HHV-6A and HHV-6B infection, but suggest that these viruses are unlikely to play a role in the pathogenesis of CFS.

George K. Rapid, simple influenza RNA extraction from nasopharyngeal samples

This report describes the development and pre-clinical testing of a new, random-access RNA sample preparation system (TruTip) for nasopharyngeal samples. The system is based on a monolithic, porous nucleic acid binding matrix embedded within an aerosol-resistant pipette tip and can be operated with single or multi-channel pipettors. Equivalent extraction efficiencies were obtained between automated QIAcube and manual TruTip methods at 10(6) gene copies influenza A per mL nasopharyngeal aspirate. Influenza A and B amended into nasopharyngeal swabs (in viral transport medium) were detected by real-time RT-PCR at approximately 745 and 370 gene copies per extraction, respectively. RNA extraction efficiency in nasopharyngeal swabs was also comparable to that obtained on an automated QIAcube instrument over a range of input concentrations; the correlation between threshold cycles (or nucleic acid recovery) for TruTip and QIAcube-purified RNA was R(2)>0.99. Preclinical testing of TruTip on blinded nasopharyngeal swab samples resulted in 98% detection accuracy relative to a clinically validated easyMAG extraction method. The physical properties of the TruTip binding matrix and ability to customize its shape and dimensions likewise make it amenable to automation and/or fluidic integration.

Detection of herpes simplex virus (1 and 2), varicella-zoster virus, cytomegalovirus, human herpesvirus 6 and enterovirus in immunocompetent Tunisian patients with acute neuromeningeal disorder

Enteroviruses (EVs) and human herpesviruses (HHVs) are involved frequently in acute neurological disorders of viral etiology. This study aimed to investigate the incidence of herpes simplex virus types-1 (HSV-1) and 2 (HSV-2), varicella-zoster virus (VZV), cytomegalovirus (CMV), human herpesvirus 6 (HHV-6) and human enteroviruses (EVs) in cerebrospinal fluid (CSF) samples of Tunisian immunocompetent patients with neuromeningeal disorders. The patients had been hospitalized at the Fattouma Bourguiba University Hospital (Monastir, Tunisia) between September 2007 and June 2009. At least one viral genome was detected in 58 (46%) out of 126 CSF samples collected. Enterovirus was detected in 31 of the positive samples (53.4%), CMV in 20 (34.5%), HSV-1 in 3 (5.2%), HSV-2 in 6 (10.3%), VZV in 4 (6.9%), HHV-6 in 2 (3.4%). More than one viral genome was detected in seven CSF samples, including CMV DNA in six of the samples. The high frequency of enteroviral infections in aseptic meningitis was confirmed. The detection of CMV DNA only suggests a direct role of this virus in the etiology of acute neuromeningeal disorder.

Development of a human herpesvirus 6 species-specific immunoblotting assay

In order to assess the full spectrum of human herpesvirus 6A (HHV-6A)- and HHV-6B-associated diseases, we sought to develop an HHV-6 species-specific serological assay based on immunoblot analysis. The immunodominant proteins encoded by open reading frame U11, p100 for HHV-6A (strain U1102) and 101K for HHV-6B (strain Z29), were selected to generate virus species-specific antigens. Recombinant p100 and 101K were produced in a prokaryotic expression system. The expression of these proteins was confirmed by using anti-His tag and 101K-specific monoclonal antibodies. HHV-6 species-specific antibodies were detected by immunoblotting in patient sera. Eighty-seven serum samples obtained from various subjects were utilized to determine the reliability of the method for clinical use. Ten of twelve exanthem subitum convalescent-phase sera reacted exclusively with 101K, whereas none of twelve acute-phase sera reacted with either protein. Two of three sera collected from HHV-6A-infected patients reacted with p100 and 101K. Although all five acute and convalescent-phase sera obtained from transplant recipients reacted exclusively with 101K, two of six convalescent-phase sera obtained from patients with drug-induced hypersensitivity syndrome reacted with both p100 and 101K. Of 38 sera obtained from healthy adults, 31 were positive for 101K antibody, while 4 reacted with both proteins. However, PCR analysis of peripheral blood mononuclear cells and saliva from these subjects did not detect HHV-6A DNA. In conclusion, this novel serological assay based on immunoblot analysis using recombinant HHV-6A p100 and HHV-6B 101K allowed us to discriminate between HHV-6A- and HHV-6B-specific antibodies.

Subtype-specific, probe-based, real-time PCR for detection and typing of human herpesvirus-6 encephalitis from pediatric patients under the age of 2 years

To investigate the frequency of human herpesvirus-6 (HHV-6) encephalitis in pediatric patients under 2 years of age, we developed a method for the simultaneous detection and differentiation of the 2 variants of HHV-6 (HHV-6A and HHV-6B) using subtype-specific, probe-based, real-time PCR (SSPBRT-PCR) and which were further evaluated on 405 cerebrospinal fluid (CSF) specimens from children with suspected encephalitis. A total of 23 (5.70%) out of 405 CSF specimens were positive by SSPBRT-PCR, including 3 cases of HHV-6A and 20 cases of HHV-6B. The positive rate of HHV-6B was significantly higher than that of HHV-6A (P = 0.0004). Compared with the results of the conventional real-time PCR, the sensitivity and specificity of the SSPBRT-PCR assay were 95.24% and 99.22%, respectively. This study suggests a role for both variants of HHV-6 in the pathogenesis of viral encephalitis. SSPBRT-PCR can provide rapid, sensitive, and specific results for identification of HHV-6A and HHV-6B and management of HHV-6 encephalitis.

Different characteristics of human herpesvirus 6 encephalitis between primary infection and viral reactivation

BACKGROUND

Pathogenesis of human herpesvirus 6 (HHV-6) encephalitis, in particular difference between HHV-6 encephalitis at the time of primary infection and reactivation remains unclear.

OBJECTIVES

To elucidate the mechanism of HHV-6 encephalitis at the time of primary infection and reactivation.

STUDY DESIGN

Twenty-two HHV-6 encephalitis patients at the time of primary infection, 6 febrile convulsion (FC) patients caused by HHV-6 infection, and 14 FC patients without HHV-6 infection (non HHV-6 FC) were enrolled. Additionally, 7 stem cell transplant recipients with HHV-6 encephalitis and eight adult controls were also enrolled in this study. Cerebrospinal fluid (CSF) HHV-6 DNA copy numbers and biomarkers levels were compared.

RESULTS

Low copy number of CSF HHV-6 DNA was detected in 7 of the 22 patients with HHV-6 encephalitis in primary infection, whereas all seven CSF samples collected from post-transplant HHV-6 encephalitis patients contained high viral DNA copy numbers (P<0.001). CSF concentrations of IL-6 (P=0.032), IL-8 (P=0.014), MMP-9 (P=0.004), and TIMP-1 (P=0.002) were significantly higher in patients with HHV-6 encephalitis in primary infection than non-HHV-6 FC. CSF IL-6 (P=0.008), IL-8 (P=0.015), and IL-10 (P=0.019) concentrations were significantly higher in patients with post-transplant HHV-6 encephalitis than adult controls.

CONCLUSION

The present study suggests that the characteristics of HHV-6 encephalitis are different between HHV-6 encephalitis at the time of primary infection and reactivation in transplant recipients.

Detection of DNA of six human herpesviruses in the cerebrospinal fluid of immunocompetent non-herpetic acute limbic encephalitis patients

In order to determine whether six other human herpesviruses, aside from herpes simplex virus, are associated with non-herpetic acute limbic encephalitis in immunocompetent individuals, real-time PCR was used to detect the DNA of herpesviruses in CSF collected from 61 patients with this form of encephalitis. Five of the human herpesviruses tested were not detected in any of the 61 CSF samples. EBV DNA was detected in one CSF sample. The EBV DNA-positive patient was a 36-year-old woman who presented with fever, headache, mild somnolence, and the typical neuroimaging findings.

High-dose ganciclovir in HHV-6 encephalitis of an immunocompetent child

Encephalitis and other neurologic complications, including acute necrotizing encephalopathy, are associated with human herpesvirus-6 infection. Antiviral treatment against human herpesvirus-6 infection is indicated only for immunocompromised patients. We describe a 15-month-old immunocompetent child with severe human herpesvirus-6-induced encephalitis. The primary infection was characterized by human herpesvirus-6 DNA in cerebrospinal fluid and serum, the presence of serum human herpesvirus-6 immunoglobulin M antibodies, and a rise in serum human herpesvirus-6 immunoglobulin G antibodies. Magnetic resonance imaging demonstrated multiple, partly symmetric, necrotic lesions in the pons, medulla oblongata, thalamus, external capsules, and occipital subcortical and cortical areas. High-dose ganciclovir (18 mg/kg/day) was used as antiviral treatment, without side effects. A pharmacokinetic analysis of ganciclovir was performed. The initial recovery from severe disease was good. At 3-year follow-up, neurologic sequelae included epilepsy and ataxia. This case suggests that treatment with ganciclovir should be considered in human herpesvirus-6 central nervous system infections because the neurologic sequelae may otherwise be severe. Controlled, prospective, clinical trials are warranted, to analyze the pharmacokinetics of ganciclovir in infants.

Direct detection of human herpesvirus 6 DNA in serum by variant specific loop-mediated isothermal amplification in hematopoietic stem cell transplant recipients

A variant specific direct loop-mediated isothermal amplification (LAMP) method was developed to detect human herpesvirus-6 (HHV-6) variants in serum samples. Specific primers were designed against HHV-6 U86 gene. Initial validation analysis confirmed high specificity and sensitivity of the method. This method was shown to be highly reliable for monitoring active HHV-6 infection in hematopoietic stem cell transplant recipients.

A duplex real-time reverse transcriptase polymerase chain reaction assay for the detection of California serogroup and Cache Valley viruses

A duplex TaqMan real-time reverse transcriptase polymerase chain reaction (PCR) assay was developed for the detection of California (CAL) serogroup viruses and Cache Valley virus (CVV), for use in human surveillance. The targets selected for the assay were the sequences encoding the nucleocapsid protein of CAL and the G1 glycoprotein of CVV. Conserved regions were selected by aligning genetic sequences from various strains available in the GenBank database. Primers and probes were selected in conserved regions. The assay sensitivity was 75 gene copies (gc)/reaction for CAL serogroup viruses and 30 gc/reaction for CVV. The performance of the assay was linear over at least 6 log(10) gc. The assay was specific, given that it did not cross-react with a variety of pathogens. It did, however, detect 11 viruses within the CAL serogroup and 12 CVV isolates. The use of an internal control ensured that possible inefficiency in nucleic acid extraction or PCR inhibition would be detected.

Sensitive, qualitative detection of human herpesvirus-6 and simultaneous differentiation of variants A and B

BACKGROUND

The current limitations of laboratory testing for the detection of human herpesvirus virus 6 (HHV-6) in clinical specimens with low HHV-6 viral loads make this area a priority for further research and development.

OBJECTIVES

To develop and validate a sensitive qualitative assay for simultaneous HHV-6 detection and variant differentiation.

METHODS

We developed a diagnostic procedure, which combines a magnetic bead-based nucleic acid extraction, PCR amplification, and colorimetric microtiter plate identification (MAG-PCR-EIA), for the sensitive detection of HHV-6 and the simultaneous differentiation of HHV-6A and HHV-6B.

RESULTS

Analytic sensitivities of the MAG-PCR-EIA assay were 10 copies per reaction for both HHV-6A and HHV-6B variants, which is equivalent to 20 copies/ml when 1ml of clinical specimen was processed. A proficiency panel containing 11 blinded specimens covering HHV-6A viral loads from 0 to 100,000 copies was tested, and the MAG-PCR-EIA was able to detect the lowest concentration at one copy in 200microl. A panel of 27 urine specimens, which were collected from patients with and without chronic fatigue syndrome, was tested by the MAG-PCR-EIA. HHV-6 was detected in two (HHV-6A) patients who have chromosomally integrated HHV-6A and in one (HHV-6B) patient who was a healthy control and diagnosed as cervical cancer later on. The HHV-6 results did not correlate with results previously determined by HHV-6 antigenemia in urine.

CONCLUSION

With large specimen volumes processed and an additional signal amplification incorporated, the MAG-PCR-EIA provides a sensitive and qualitative system for HHV-6 detection and simultaneous variant differentiation. Clinical relevance of the assay awaits further investigation.

Effect of (r)-9-[4-hydroxy-2-(hydroxymethyl)butyl]guanine (H2G) and AZT-lipid-PFA on human herpesvirus-6B infected cells

BACKGROUND

Human herpesvirus-6 (HHV-6) has been associated with a wide spectrum of diseases. (r)-9-[4-Hydroxy-2-(hydroxymethyl)butyl]guanine (H2G) is an acyclic guanosine analogue that is structurally similar to acyclovir and is in clinical development for treatment of herpesvirus infections. H2G has been found to have activity against HSV type 1, HSV type 2, and HHV-6 in lymphoblast cell lines. A new anti-viral duplex drug, 3'-azido-3'-deoxythymidylyl-(5'-->2-O)-3-O-octadecyl-sn-glycerol (AZT-lipid-PFA), linking zidovudine (AZT) and foscarnet (PFA) via a lipophilic octadecylglycerol residue (lipid) also exhibits anti-viral activities against HIV, HSV type 1 and HCMV.

OBJECTIVE

To assess the efficacy of H2G and AZT-lipid-PFA conjugate against HHV-6.

STUDY DESIGN

Drug-associated toxicity and proliferative response were evaluated. We conducted in vitro experiments to determine the efficacy of H2G and an AZT-lipid-PFA conjugate in interfering with expression HHV-6 viral transcript in primary human peripheral blood mononuclear cells (PBMC).

RESULTS

Both H2G and AZT-lipid-PFA were effective at inhibiting expression of HHV-6 gene transcript at comparable concentrations. Additionally, while AZT-lipid-PFA treatment was toxic to cells at concentrations above 5microM, H2G treatment was associated with minimal cytotoxicity.

CONCLUSION

These data suggest the potential application of these anti-viral compounds in controlling HHV-6 infection.

Sensitivity of human herpesvirus 6 and other human herpesviruses to the broad-spectrum antiinfective drug artesunate

BACKGROUND

Antiviral therapy for HHV-6 infection with conventional anti-herpesviral drugs is problematic so novel drugs are required. Artesunate is a well-tolerated drug approved for malaria therapy which possesses antiviral activity.

OBJECTIVE

The artesunate sensitivity of HHV-6 was analyzed and compared to that of several other human herpesviruses.

STUDY DESIGN

Cultured human cells were productively infected with strains of HHV-6 or other human herpesviruses to measure artesunate inhibition of viral protein synthesis (Western blot analysis) or viral genome replication (qPCR), and to determine IC(50) values by immunofluorescence or plaque reduction assays.

RESULTS

Sensitivity of HHV-6 to artesunate was demonstrated with an IC(50) of 3.80+/-1.06microM. This is in a range similar to IC(50) values for HCMV and EBV. Artesunate treatment of HHV-6-infected cells significantly reduced viral early and late protein synthesis that occurred in the absence of drug-induced apoptosis or necrotic cytotoxicity. HHV-6A genome replication was markedly reduced by artesunate.

CONCLUSIONS

Artesunate possesses anti-HHV-6 activity in vitro and may be useful for treatment of HHV-6 infections.

Detection of human herpesvirus-6 in cerebrospinal fluid of patients with encephalitis

OBJECTIVE

Virus infections are the most common causes of encephalitis, a syndrome characterized by acute inflammation of the brain. More than 150 different viruses have been implicated in the pathogenesis of encephalitis; however, because of limitations with diagnostic testing, causative factors of more than half of the cases remain unknown.

METHODS

To investigate whether human herpesvirus-6 (HHV-6) is a causative agent of encephalitis, we examined for evidence of virus infection by determining the presence of viral sequence using polymerase chain reaction and assessed HHV-6 antibody reactivity in the cerebrospinal fluid of encephalitis patients with unknown cause. In a cohort study, we compared virus-specific antibody levels in cerebrospinal fluid samples of patients with encephalitis, relapsing-remitting multiple sclerosis, and other neurological diseases.

RESULTS

Our results demonstrated increased levels of HHV-6 IgG, as well as IgM levels, in a subset of encephalitis patients compared with other neurological diseases. Moreover, cell-free viral DNA that is indicative of active infection was detected in 40% (14/35) of encephalitis patients, whereas no amplifiable viral sequence was found in either relapsing-remitting MS or other neurological diseases patients. In addition, a significant correlation between polymerase chain reaction detection and anti-HHV-6 antibody response was also demonstrated.

INTERPRETATION

Collectively, these results suggested HHV-6 as a possible pathogen in a subset of encephalitis cases.

A duplex real-time reverse transcriptase polymerase chain reaction assay for the detection of St. Louis encephalitis and eastern equine encephalitis viruses

A duplex TaqMan real-time reverse transcriptase polymerase chain reaction (PCR) assay was developed for the detection of St. Louis encephalitis virus (SLEV) and eastern equine encephalitis virus (EEEV), for use in human and vector surveillance. The respective targets selected for the assay were the conserved NS5 and E1 genes of the 2 viruses. Because of the insufficient number of NS5 sequences from SLEV strains in the GenBank database, we determined the sequence of an approximately 1-kb region for each of 25 strains of SLEV to select primers and probes in a conserved region. Our assay has a sensitivity of 5 gene copies (gc)/reaction for EEEV and 10 gc/reaction for SLEV, and its performance is linear for at least 6 log(10) gc. The assay is specific and detected all strains of SLEV (69) and EEEV (12) that were tested. An internal control ensures detection of efficient nucleic acid extraction and possible PCR inhibition.

Loop-mediated isothermal amplification for discriminating between human herpesvirus 6 A and B

Genotyping of human herpesvirus 6 (HHV-6) is important clinically, particularly for the diagnosis of neurological diseases. The objective of this study was to establish a rapid HHV-6 genotyping method using the loop-mediated isothermal amplification (LAMP) method. An AccI site is located in the target sequence of HHV-6 B, but not in HHV-6 A. LAMP products were digested with the AccI enzyme and then separated by agarose gel electrophoresis to differentiate the digest pattern of the two variants. The fragment patterns were clearly different between HHV-6 A and B. In order to evaluate the reliability of this HHV-6 genotyping method for use in the clinical laboratory, serum samples from 20 patients with either primary HHV-6 infection or viral reactivation were collected and analyzed. HHV-6 DNA was amplified directly from the serum samples and all 20 LAMP products were positive for HHV-6 B.