Varicella-zoster virus recapitulates its immune evasive behaviour in matured hiPSC-derived neurospheroids.

Varicella-zoster virus (VZV) encephalitis and meningitis are potential central nervous system (CNS) complications following primary VZV infection or reactivation. With Type-I interferon (IFN) signalling being an important first line cellular defence mechanism against VZV infection by the peripheral tissues, we here investigated the triggering of innate immune responses in a human neural-like environment. For this, we established and characterised 5-month matured hiPSC-derived neurospheroids (NSPHs) containing neurons and astrocytes. Subsequently, NSPHs were infected with reporter strains of VZV (VZVeGFP-ORF23) or Sendai virus (SeVeGFP), with the latter serving as an immune-activating positive control. Live cell and immunocytochemical analyses demonstrated VZVeGFP-ORF23 infection throughout the NSPHs, while SeVeGFP infection was limited to the outer NSPH border. Next, NanoString digital transcriptomics revealed that SeVeGFP-infected NSPHs activated a clear Type-I IFN response, while this was not the case in VZVeGFP-ORF23-infected NSPHs. Moreover, the latter displayed a strong suppression of genes related to IFN signalling and antigen presentation, as further demonstrated by suppression of IL-6 and CXCL10 production, failure to upregulate Type-I IFN activated anti-viral proteins (Mx1, IFIT2 and ISG15), as well as reduced expression of CD74, a key-protein in the MHC class II antigen presentation pathway. Finally, even though VZVeGFP-ORF23-infection seems to be immunologically ignored in NSPHs, its presence does result in the formation of stress granules upon long-term infection, as well as disruption of cellular integrity within the infected NSPHs. Concluding, in this study we demonstrate that 5-month matured hiPSC-derived NSPHs display functional innate immune reactivity towards SeV infection, and have the capacity to recapitulate the strong immune evasive behaviour towards VZV.

Molecular Study of Varicella zoster virus in Cerebrospinal Fluid from Stroke Patients of Thi-Qar province.

INTRODUCTION: Varicella zoster virus (VZV) is a type of alpha-herpesvirus that specifically targets the nervous system. The initial infection, typically occurring during childhood, results in varicella (commonly known as chickenpox), after which the virus enters a dormant state in cranial nerve ganglia, dorsal root ganglia, and autonomic ganglia throughout the entire neuroaxis. AIM OF THE STUDY: Molecular and genetic studies of viruses are an important tool for virus development and identifying viral treatments to combat the diseases. The aim of the study was to determine the whole ORF4 sequence of the local VZV strains for phylogenetic analysis to determine the variability in the viral sequence. MATERIAL AND METHODS: Ten samples of VZV DNA were subjected to the sequencing of the whole ORF4 region following identification using the PCR method. RESULTS: Sequences from five samples have been successfully analyzed. All clinical strains were discovered to possess a genome with a length of 124,884 base pairs. The sequences exhibited the occurrence of two distinct mutations, one being a transversion and the other a transition, with the latter resulting in an alteration of the amino acid. A phylogenetic tree was constructed using the maximum likelihood method based on the sequences of five nucleotide sequences from clinical samples and nine reference VZV strains. The tree displayed the evolutionary distances between these sequences. The analysis of the phylogenetic tree revealed the presence of five primary clades, with four of them originating from India (isolates S1, S2, S4, S5), while S3 exhibited similarity to a strain from the United Kingdom.

Varicella Zoster Virus disrupts MAIT cell polyfunctional effector responses.

Mucosal-associated invariant T (MAIT) cells are unconventional T cells that respond to riboflavin biosynthesis and cytokines through TCR-dependent and -independent pathways, respectively. MAIT cell activation plays an immunoprotective role against several pathogens, however the functional capacity of MAIT cells following direct infection or exposure to infectious agents remains poorly defined. We investigated the impact of Varicella Zoster Virus (VZV) on blood-derived MAIT cells and report virus-mediated impairment of activation, cytokine production, and altered transcription factor expression by VZV infected (antigen+) and VZV exposed (antigen-) MAIT cells in response to TCR-dependent and -independent stimulation. Furthermore, we reveal that suppression of VZV exposed (antigen-) MAIT cells is not mediated by a soluble factor from neighbouring VZV infected (antigen+) MAIT cells. Finally, we demonstrate that VZV impairs the cytolytic potential of MAIT cells in response to riboflavin synthesising bacteria. In summary, we report a virus-mediated immune-evasion strategy that disarms MAIT cell responses.

Suppression of the host antiviral response by non-infectious varicella zoster virus extracellular vesicles.

Varicella zoster virus (VZV) reactivates from ganglionic sensory neurons to produce herpes zoster (shingles) in a unilateral dermatomal distribution, typically in the thoracic region. Reactivation not only heightens the risk of stroke and other neurological complications but also increases susceptibility to co-infections with various viral and bacterial pathogens at sites distant from the original infection. The mechanism by which VZV results in complications remote from the initial foci remains unclear. Small extracellular vesicles (sEVs) are membranous signaling structures that can deliver proteins and nucleic acids to modify the function of distal cells and tissues during normal physiological conditions. Although viruses have been documented to exploit the sEV machinery to propagate infection, the role of non-infectious sEVs released from VZV-infected neurons in viral spread and disease has not been studied. Using multi-omic approaches, we characterized the content of sEVs released from VZV-infected human sensory neurons (VZV sEVs). One viral protein was detected (immediate-early 62), as well as numerous immunosuppressive and vascular disease-associated host proteins and miRNAs that were absent in sEVs from uninfected neurons. Notably, VZV sEVs are non-infectious yet transcriptionally altered primary human cells, suppressing the antiviral type 1 interferon response and promoting neuroinvasion of a secondary pathogen in vivo. These results challenge our understanding of VZV infection, proposing that the virus may contribute to distant pathologies through non-infectious sEVs beyond the primary infection site. Furthermore, this study provides a previously undescribed immune-evasion mechanism induced by VZV that highlights the significance of non-infectious sEVs in early VZV pathogenesis. IMPORTANCE: Varicella zoster virus (VZV) is a ubiquitous human virus that predominantly spreads by direct cell-cell contact and requires efficient and immediate host immune evasion strategies to spread. The mechanisms of immune evasion prior to virion entry have not been fully elucidated and represent a critical gap in our complete understanding of VZV pathogenesis. This study describes a previously unreported antiviral evasion strategy employed by VZV through the exploitation of the infected host cell's small extracellular vesicle (sEV) machinery. These findings suggest that non-infectious VZV sEVs could travel throughout the body, affecting cells remote from the site of infection and challenging the current understanding of VZV clinical disease, which has focused on local effects and direct infection. The significance of these sEVs in early VZV pathogenesis highlights the importance of further investigating their role in viral spread and secondary disease development to reduce systemic complications following VZV infections.

A unique case of double meningitis with enterovirus and reactivated varicella-zoster virus in a male teenager.

This paper presents a unique case of double meningitis with enterovirus and reactivated varicella-zoster virus without shingles in an immunocompetent male teenager, a case that offers many important medical lessons, all "gravitating" around physiopathological reasoning of any clinical case in general.

Viral modulation of type II interferon increases T cell adhesion and virus spread.

During primary varicella zoster virus (VZV) infection, infected lymphocytes drive primary viremia, causing systemic dissemination throughout the host, including the skin. This results in cytokine expression, including interferons (IFNs), which partly limit infection. VZV also spreads from skin keratinocytes to lymphocytes prior to secondary viremia. It is not clear how VZV achieves this while evading the cytokine response. Here, we show that VZV glycoprotein C (gC) binds IFN-γ and modifies its activity, increasing the expression of a subset of IFN-stimulated genes (ISGs), including intercellular adhesion molecule 1 (ICAM1), chemokines and immunomodulatory genes. The higher ICAM1 protein level at the plasma membrane of keratinocytes facilitates lymphocyte function-associated antigen 1-dependent T cell adhesion and expression of gC during infection increases VZV spread to peripheral blood mononuclear cells. This constitutes the discovery of a strategy to modulate IFN-γ activity, upregulating a subset of ISGs, promoting enhanced lymphocyte adhesion and virus spread.

Varicella-zoster virus-related neurological complications: From infection to immunomodulatory therapies.

The Varicella-zoster virus (VZV), classified as a neurotropic member of the Herpesviridae family, exhibits a characteristic pathogenicity, predominantly inducing varicella, commonly known as chickenpox, during the initial infectious phase, and triggering the reactivation of herpes zoster, more commonly recognized as shingles, following its emergence from a latent state. The pathogenesis of VZV-associated neuroinflammation involves a complex interplay between viral replication within sensory ganglia and immune-mediated responses that contribute to tissue damage and dysfunction. Upon primary infection, VZV gains access to sensory ganglia, establishing latent infection within neurons. During reactivation, the virus can spread along sensory nerves, triggering a cascade of inflammatory mediators, chemokines, and immune cell infiltration in the affected neural tissues. The role of both adaptive and innate immune reactions, including the contributions of T and B cells, macrophages, and dendritic cells, in orchestrating the immune-mediated damage in the central nervous system is elucidated. Furthermore, the aberrant activation of the natural defence mechanism, characterised by the dysregulated production of immunomodulatory proteins and chemokines, has been implicated in the pathogenesis of VZV-induced neurological disorders, such as encephalitis, myelitis, and vasculopathy. The intricate balance between protective and detrimental immune responses in the context of VZV infection emphasises the necessity for an exhaustive comprehension of the immunopathogenic mechanisms propelling neuroinflammatory processes. Despite the availability of vaccines and antiviral therapies, VZV-related neurological complications remain a significant concern, particularly in immunocompromised individuals and the elderly. Elucidating these mechanisms might facilitate the emergence of innovative immunomodulatory strategies and targeted therapies aimed at mitigating VZV-induced neuroinflammatory damage and improving clinical outcomes. This comprehensive understanding enhances our grasp of viral pathogenesis and holds promise for pioneering therapeutic strategies designed to mitigate the neurological ramifications of VZV infections.

Identification and characterization of Varicella Zoster Virus circular RNA in lytic infection.

This study investigates the role of circular RNAs (circRNAs) in the context of Varicella-Zoster Virus (VZV) lytic infection. We employ two sequencing technologies, short-read sequencing and long-read sequencing, following RNase R treatment on VZV-infected neuroblastoma cells to identify and characterize both cellular and viral circRNAs. Our large scanning analysis identifies and subsequent experiments confirm 200 VZV circRNAs. Moreover, we discover numerous VZV latency-associated transcripts (VLTs)-like circRNAs (circVLTslytic), which contain multiple exons and different isoforms within the same back-splicing breakpoint. To understand the functional significance of these circVLTslytic, we utilize the Bacteria Artificial Chromosome system to disrupt the expression of viral circRNAs in genomic DNA location. We reveal that the sequence flanking circVLTs' 5' splice donor plays a pivotal role as a cis-acting element in the formation of circVLTslytic. The circVLTslytic is dispensable for VZV replication, but the mutation downstream of circVLTslytic exon 5 leads to increased acyclovir sensitivity in VZV infection models. This suggests that circVLTslytic may have a role in modulating the sensitivity to antiviral treatment. The findings shed new insight into the regulation of cellular and viral transcription during VZV lytic infection, emphasizing the intricate interplay between circRNAs and viral processes.

Varicella zoster virus-induced autophagy in human neuronal and hematopoietic cells exerts antiviral activity.

Autophagy is a degradational pathway with pivotal roles in cellular homeostasis and survival, including protection of neurons in the central nervous system (CNS). The significance of autophagy as antiviral defense mechanism is recognized and some viruses hijack and modulate this process to their advantage in certain cell types. Here, we present data demonstrating that the human neurotropic herpesvirus varicella zoster virus (VZV) induces autophagy in human SH-SY5Y neuronal cells, in which the pathway exerts antiviral activity. Productively VZV-infected SH-SY5Y cells showed increased LC3-I-LC3-II conversion as well as co-localization of the viral glycoprotein E and the autophagy receptor p62. The activation of autophagy was dependent on a functional viral genome. Interestingly, inducers of autophagy reduced viral transcription, whereas inhibition of autophagy increased viral transcript expression. Finally, the genotype of patients with severe ocular and brain VZV infection were analyzed to identify potential autophagy-associated inborn errors of immunity. Two patients expressing genetic variants in the autophagy genes ULK1 and MAP1LC3B2, respectively, were identified. Notably, cells of both patients showed reduced autophagy, alongside enhanced viral replication and death of VZV-infected cells. In conclusion, these results demonstrate a neuro-protective role for autophagy in the context of VZV infection and suggest that failure to mount an autophagy response is a potential predisposing factor for development of severe VZV disease.

Construction of a pathological model of skin lesions in acute herpes zoster virus infection and its molecular mechanism.

Varicella-zoster virus (VZV), a common pathogen with humans as the sole host, causes primary infection and undergoes a latent period in sensory ganglia. The recurrence of VZV is often accompanied by severe neuralgia in skin tissue, which has a serious impact on the life of patients. During the acute infection of VZV, there are few related studies on the pathophysiological mechanism of skin tissue. In this study, transcriptome sequencing data from the acute response period within 2 days of VZV antigen stimulation of the skin were used to explore a model of the trajectory of skin tissue changes during VZV infection. It was found that early VZV antigen stimulation caused activation of mainly natural immune-related signaling pathways, while in the late phase activation of mainly active immune-related signaling pathways. JAK-STAT, NFκB, and TNFα signaling pathways are gradually activated with the progression of infection, while Hypoxia is progressively inhibited. In addition, we found that dendritic cell-mediated immune responses play a dominant role in the lesion damage caused by VZV antigen stimulation of the skin. This study provides a theoretical basis for the study of the molecular mechanisms of skin lesions during acute VZV infection.

Regulation of Siglec-7-mediated varicella-zoster virus infection of primary monocytes by cis-ligands.

Varicella-zoster virus (VZV) first infects hematopoietic cells, with the infected cells then acting to distribute the virus throughout the body. Sialic acid-binding immunoglobulin-like lectin (Siglec) family molecules recognize sialic acid-containing molecules on the same cell surface, called cis-ligands, or molecules on other cells or soluble agents, called trans-ligands. Among the Siglec family molecules, Siglec-4 and Siglec-7 mediate VZV infection through association with glycoprotein B (gB). As Siglec-7, but not Siglec-4, is expressed on hematopoietic cells such as monocytes, the regulatory mechanism by which Siglec-7 associates with gB is important to our understanding of VZV infection of blood cells. Here, we found that Siglec-7 is required for VZV to infect human primary monocytes. Furthermore, treatment of primary monocytes with sialidase enhanced both VZV gB binding to monocytes and VZV infectivity. Calcium influx in primary monocytes decreased the expression of Siglec-7 cis-ligands and increased VZV infectivity. These results demonstrate that the Siglec-7 cis-ligands present on primary monocytes play an important role in VZV infection through regulation of the interaction between gB and Siglec-7.

Anti-varicella zoster virus and related anti-inflammation effects of ethanolic extract of Elaeocarpus sylvestris.

ETHNOPHARMACOLOGICAL RELEVANCE: Elaeocarpus sylvestris var. ellipticus (ES), a plant that grows in Taiwan, Japan, and Jeju Island in Korea. ES root bark, known as "sanduyoung," has long been used in traditional oriental medicine. ES is also traditionally used to treat anxiety, asthma, arthritis, stress, depression, palpitation, nerve pain, epilepsy, migraine, hypertension, liver diseases, diabetes, and malaria. However, lack of efficacy and mechanism studies on ES. AIM OF THE STUDY: In the present study, we aim to investigate the VZV-antiviral efficacy, pain suppression, and the anti-inflammatory and antipyretic effects of ES. METHODS: and methods: Inhibition of VZV was evaluated by hollow fiber assays. Analgesic and antipyretic experiments were conducted using ICR mice and SD Rats, and anti-inflammatory experiments were conducted using Raw264.7 cells. RESULTS: To evaluate the efficacy of ESE against VZV, we conducted antiviral tests. ESE inhibited cell death by disrupting virus and gene expression related to invasion and replication. In addition, ESE suppressed the pain response as measured by writhing and formalin tests and suppressed LPS-induced inflammatory fever. Further, ESE inhibited the phosphorylation of IκB and NF-κB in LPS-induced Raw264.7 cells and expression of COX-2, iNOS, IL-1ß, IL-6, and TNF-α. CONCLUSION: E. sylvestris shows potential as a source of medicine. ESE had a direct effect on VZV and an inhibitory effect on the pain and inflammation caused by VZV infection.

Targeted RNA Sequencing of VZV-Infected Brain Vascular Adventitial Fibroblasts Indicates That Amyloid May Be Involved in VZV Vasculopathy.

BACKGROUND AND OBJECTIVES: Compared with stroke controls, patients with varicella zoster virus (VZV) vasculopathy have increased amyloid in CSF, along with increased amylin (islet amyloid polypeptide [IAPP]) and anti-VZV antibodies. Thus, we examined the gene expression profiles of VZV-infected primary human brain vascular adventitial fibroblasts (HBVAFs), one of the initial arterial cells infected in VZV vasculopathy, to determine whether they are a potential source of amyloid that can disrupt vasculature and potentiate inflammation. METHODS: Mock- and VZV-infected quiescent HBVAFs were harvested at 3 days postinfection. Targeted RNA sequencing of the whole-human transcriptome (BioSpyder Technologies, TempO-Seq) was conducted followed by gene set enrichment and pathway analysis. Selected pathways unique to VZV-infected cells were confirmed by enzyme-linked immunoassays, migration assays, and immunofluorescence analysis (IFA) that included antibodies against amylin and amyloid-beta, as well as amyloid staining by Thioflavin-T. RESULTS: Compared with mock, VZV-infected HBVAFs had significantly enriched gene expression pathways involved in vascular remodeling and vascular diseases; confirmatory studies showed secretion of matrix metalloproteinase-3 and -10, as well increased migration of infected cells and uninfected cells when exposed to conditioned media from VZV-infected cells. In addition, significantly enriched pathways involved in amyloid-associated diseases (diabetes mellitus, amyloidosis, and Alzheimer disease), tauopathy, and progressive neurologic disorder were identified; predicted upstream regulators included amyloid precursor protein, apolipoprotein E, microtubule-associated protein tau, presenilin 1, and IAPP. Confirmatory IFA showed that VZV-infected HBVAFs contained amyloidogenic peptides (amyloid-beta and amylin) and intracellular amyloid. DISCUSSION: Gene expression profiles and pathway enrichment analysis of VZV-infected HBVAFs, as well as phenotypic studies, reveal features of pathologic vascular remodeling (e.g., increased cell migration and changes in the extracellular matrix) that can contribute to cerebrovascular disease. Furthermore, the discovery of amyloid-associated transcriptional pathways and intracellular amyloid deposition in HBVAFs raise the possibility that VZV vasculopathy is an amyloid disease. Amyloid deposition may contribute to cell death and loss of vascular wall integrity, as well as potentiate chronic inflammation in VZV vasculopathy, with disease severity and recurrence determined by the host's ability to clear virus infection and amyloid deposition and by the coexistence of other amyloid-associated diseases (i.e., Alzheimer disease and diabetes mellitus).

Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease and Varicella Zoster Virus Infection - Frequency of an Association.

To determine whether there is a correlation between myelin oligodendrocyte glycoprotein (MOG) antibody-associated diseases and varicella zoster virus (VZV) infection. We provide a case report and performed a study to determine the frequency of MOG antibodies (MOG-IgG) in neurological VZV infections. Patients admitted to the Medical University of Innsbruck from 2008-2020 with a diagnosis of a neurological manifestation of VZV infection (n=59) were included in this study; patients with neuroborreliosis (n=34) served as control group. MOG-IgG was detected using live cell-based assays. In addition, we performed a literature review focusing on MOG and aquaporin-4 (AQP4) antibodies and their association with VZV infection. Our case presented with VZV-associated longitudinally extensive transverse myelitis and had MOG-IgG at a titer of 1:1280. In the study, we did not detect MOG-IgG in any other patient neither in the VZV group (including 15 with VZV encephalitis/myelitis) nor in the neuroborreliosis group. In the review of the literature, 3 cases with MOG-IgG and additional 9 cases with AQP4 IgG associated disorders in association with a VZV infection were identified. MOG-IgG are rarely detected in patients with VZV infections associated with neurological diseases.

Nectin-1 Is an Entry Mediator for Varicella-Zoster Virus Infection of Human Neurons.

Varicella-zoster virus (VZV) maintains lifelong latency in neurons following initial infection and can subsequently be reactivated to result in herpes zoster or severe neurological manifestations such as encephalitis. Mechanisms of VZV neuropathogenesis have been challenging to study due to the strict human tropism of the virus. Although neuronal entry mediators of other herpesviruses, including herpes simplex virus, have been identified, little is known regarding how VZV enters neurons. Here, we utilize a human stem cell-based neuronal model to characterize cellular factors that mediate entry. Through transcriptional profiling of infected cells, we identify the cell adhesion molecule nectin-1 as a candidate mediator of VZV entry. Nectin-1 is highly expressed in the cell bodies and axons of neurons. Either knockdown of endogenous nectin-1 or incubation with soluble forms of nectin-1 produced in mammalian cells results in a marked decrease in infectivity of neurons. Notably, while addition of soluble nectin-1 during viral infection inhibits infectivity, addition after infection has no effect on infectivity. Ectopic expression of human nectin-1 in a cell line resistant to productive VZV infection confers susceptibility to infection. In summary, we have identified nectin-1 as a neuronal entry mediator of VZV. IMPORTANCE Varicella-zoster virus (VZV) causes chickenpox, gains access to neurons during primary infection where it resides lifelong, and can later be reactivated. Reactivation is associated with shingles and postherpetic neuralgia, as well as with severe neurologic complications, including vasculitis and encephalitis. Although the varicella vaccine substantially decreases morbidity and mortality associated with primary infection, the vaccine cannot prevent the development of neuronal latency, and vaccinated populations are still at risk for reactivation. Furthermore, immunocompromised individuals are at higher risk for VZV reactivation and associated complications. Little is known regarding how VZV enters neurons. Here, we identify nectin-1 as an entry mediator of VZV in human neurons. Identification of nectin-1 as a neuronal VZV entry mediator could lead to improved treatments and preventative measures to reduce VZV related morbidity and mortality.

Kallikreins emerge as new regulators of viral infections.

Kallikrein-related peptidases (KLKs) or kallikreins have been linked to diverse (patho) physiological processes, such as the epidermal desquamation and inflammation, seminal clot liquefaction, neurodegeneration, and cancer. Recent mounting evidence suggests that KLKs also represent important regulators of viral infections. It is well-established that certain enveloped viruses, including influenza and coronaviruses, require proteolytic processing of their hemagglutinin or spike proteins, respectively, to infect host cells. Similarly, the capsid protein of the non-enveloped papillomavirus L1 should be proteolytically cleaved for viral uncoating. Consequently, extracellular or membrane-bound proteases of the host cells are instrumental for viral infections and represent potential targets for drug development. Here, we summarize how extracellular proteolysis mediated by the kallikreins is implicated in the process of influenza (and potentially coronavirus and papillomavirus) entry into host cells. Besides direct proteolytic activation of viruses, KLK5 and 12 promote viral entry indirectly through proteolytic cascade events, like the activation of thrombolytic enzymes that also can process hemagglutinin, while additional functions of KLKs in infection cannot be excluded. In the light of recent evidence, KLKs represent potential host targets for the development of new antivirals. Humanized animal models to validate their key functions in viral infections will be valuable.

Deep Herpes.

Herpes viruses are known for infecting epithelial cells and manifesting as vesicles. However, herpes viruses can also infect stromal cells. While established in the ocular setting, cutaneous stromal herpes (deep herpes) is previously unreported and may evade clinical and microscopic detection. We searched for skin biopsies with herpes stromal disease. Clinical information was retrieved via electronic medical records and pathology records system. Hematoxylin and eosin slides, immunohistochemical staining, and polymerase chain reaction detection of viral DNA was performed. We identified 12 specimens from 10 patients with cutaneous stromal herpes simplex virus 1/2 (n=7) or varicella-zoster virus infection (n=5). The most common site involved was the buttocks/perianal region (n=6). Ulceration was a frequent dermatologic finding (n=8). Pyoderma gangrenosum was clinically suspected in 6 specimens (50%). Eight patients (80%) were immunosuppressed. Biopsies frequently demonstrated a dense dermal mixed inflammatory infiltrate with subcutaneous extension and enlarged cells with viral cytopathic changes confirmed by herpes simplex virus 1/2 or varicella-zoster virus immunohistochemistry (n=10) or polymerase chain reaction (n=2). Most specimens (67%) lacked evidence of characteristic epidermal keratinocyte infection. This study presents the first known report of the ability of herpes virus to infect deep stromal cells of the dermis. We raise awareness of cutaneous stromal herpes in patients presenting with atypical clinical lesions, particularly while immunocompromised. Establishing the correct diagnosis is critical for initiating therapy.

Metagenomic analysis of a throat swab sample collected in China on a patient infected with Varicella Zoster Virus.

Varicella Zoster Virus (VZV) is endemic worldwide, causing varicella in children and zoster upon reactivation in adults. This study concerned a metagenomic analysis of a throat swab sample collected in China, on a young patient suffering from Systemic Lupus Erythematosus (SLE) and diagnosed with varicella. The complete genome sequence of a VZV strain of clade 2 has been generated. Clade 2 strains are the most prevalent in Asian countries. A comparison of 223 VZV genomes identified 77 clade specific markers, 20 of them specific to clade 2. The metagenomic analysis also identified sequences covering most of the genome of the bacteria Schaalia odontolytica also known as Actinomyces odontolyticus. VZV infection and bacterial infection in the context of SLE is further discussed. Even though the patient presented only mild symptoms, this study is a reminder that vaccination against VZV is critical to avoid severe complications like bacterial superinfection or even death in the case of immunodeficiency.

Varicella-zoster virus early infection but not complete replication is required for the induction of chronic hypersensitivity in rat models of postherpetic neuralgia.

Herpes zoster, the result of varicella-zoster virus (VZV) reactivation, is frequently complicated by difficult-to-treat chronic pain states termed postherpetic neuralgia (PHN). While there are no animal models of VZV-induced pain following viral reactivation, subcutaneous VZV inoculation of the rat causes long-term nocifensive behaviors indicative of mechanical and thermal hypersensitivity. Previous studies using UV-inactivated VZV in the rat model suggest viral gene expression is required for the development of pain behaviors. However, it remains unclear if complete infection processes are needed for VZV to induce hypersensitivity in this host. To further assess how gene expression and replication contribute, we developed and characterized three replication-conditional VZV using a protein degron system to achieve drug-dependent stability of essential viral proteins. Each virus was then assessed for induction of hypersensitivity in rats under replication permissive and nonpermissive conditions. VZV with a degron fused to ORF9p, a late structural protein that is required for virion assembly, induced nocifensive behaviors under both replication permissive and nonpermissive conditions, indicating that complete VZV replication is dispensable for the induction of hypersensitivity. This conclusion was confirmed by showing that a genetic deletion recombinant VZV lacking DNA packaging protein ORF54p still induced prolonged hypersensitivities in the rat. In contrast, VZV with a degron fused to the essential IE4 or IE63 proteins, which are involved in early gene regulation of expression, induced nocifensive behaviors only under replication permissive conditions, indicating importance of early gene expression events for induction of hypersensitivity. These data establish that while early viral gene expression is required for the development of nocifensive behaviors in the rat, complete replication is dispensable. We postulate this model reflects events leading to clinical PHN, in which a population of ganglionic neurons become abortively infected with VZV during reactivation and survive, but host signaling becomes altered in order to transmit ongoing pain.