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.

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.

Simian varicella virus infection and reactivation in rhesus macaques trigger cytokine and Aß40/42 alterations in serum and cerebrospinal fluid.

Simian varicella virus (SVV) produces peripheral inflammatory responses during varicella (primary infection) and zoster (reactivation) in rhesus macaques (RM). However, it is unclear if peripheral measures are accurate proxies for central nervous system (CNS) responses. Thus, we analyzed cytokine and Aß42/Aß40 changes in paired serum and cerebrospinal fluid (CSF) during the course of infection. During varicella and zoster, every RM had variable changes in serum and CSF cytokine and Aß42/Aß40 levels compared to pre-inoculation levels. Overall, peripheral infection appears to affect CNS cytokine and Aß42/Aß40 levels independent of serum responses, suggesting that peripheral disease may contribute to CNS disease.

Extracellular vesicles in the pathogenesis of neurotropic viruses.

Neurotropic viruses, characterized by their capacity to invade the central nervous system, present a considerable challenge to public health and are responsible for a diverse range of neurological disorders. This group includes a diverse array of viruses, such as herpes simplex virus, varicella zoster virus, poliovirus, enterovirus and Japanese encephalitis virus, among others. Some of these viruses exhibit high neuroinvasiveness and neurovirulence, while others demonstrate weaker neuroinvasive and neurovirulent properties. The clinical manifestations of infections caused by neurotropic viruses can vary significantly, ranging from mild symptoms to severe life-threatening conditions. Extracellular vesicles (EVs) have garnered considerable attention due to their pivotal role in intracellular communication, which modulates the biological activity of target cells via the transport of biomolecules in both health and disease. Investigating EVs in the context of virus infection is crucial for elucidating their potential role contribution to viral pathogenesis. This is because EVs derived from virus-infected cells frequently transfer viral components to uninfected cells. Importantly, EVs released by virus-infected cells have the capacity to traverse the blood-brain barrier (BBB), thereby impacting neuronal activity and inducing neuroinflammation. In this review, we explore the roles of EVs during neurotropic virus infections in either enhancing or inhibiting viral pathogenesis. We will delve into our current comprehension of the molecular mechanisms that underpin these roles, the potential implications for the infected host, and the prospective diagnostic applications that could arise from this understanding.

Exocytosis of Progeny Infectious Varicella-Zoster Virus Particles via a Mannose-6-Phosphate Receptor Pathway without Xenophagy following Secondary Envelopment.

The literature on the egress of different herpesviruses after secondary envelopment is contradictory. In this report, we investigated varicella-zoster virus (VZV) egress in a cell line from a child with Pompe disease, a glycogen storage disease caused by a defect in the enzyme required for glycogen digestion. In Pompe cells, both the late autophagy pathway and the mannose-6-phosphate receptor (M6PR) pathway are interrupted. We have postulated that intact autophagic flux is required for higher recoveries of VZV infectivity. To test that hypothesis, we infected Pompe cells and then assessed the VZV infectious cycle. We discovered that the infectious cycle in Pompe cells was remarkably different from that of either fibroblasts or melanoma cells. No large late endosomes filled with VZV particles were observed in Pompe cells; only individual viral particles in small vacuoles were seen. The distribution of the M6PR pathway (trans-Golgi network to late endosomes) was constrained in infected Pompe cells. When cells were analyzed with two different anti-M6PR antibodies, extensive colocalization of the major VZV glycoprotein gE (known to contain M6P residues) and the M6P receptor (M6PR) was documented in the viral highways at the surfaces of non-Pompe cells after maximum-intensity projection of confocal z-stacks, but neither gE nor the M6PR was seen in abundance at the surfaces of infected Pompe cells. Taken together, our results suggested that (i) Pompe cells lack a VZV trafficking pathway within M6PR-positive large endosomes and (ii) most infectious VZV particles in conventional cell substrates are transported via large M6PR-positive vacuoles without degradative xenophagy to the plasma membrane.IMPORTANCE The long-term goal of this research has been to determine why VZV, when grown in cultured cells, invariably is more cell associated and has a lower titer than other alphaherpesviruses, such as herpes simplex virus 1 (HSV1) or pseudorabies virus (PRV). Data from both HSV1 and PRV laboratories have identified a Rab6 secretory pathway for the transport of single enveloped viral particles from the trans-Golgi network within small vacuoles to the plasma membrane. In contrast, after secondary envelopment in fibroblasts or melanoma cells, multiple infectious VZV particles accumulated within large M6PR-positive late endosomes that were not degraded en route to the plasma membrane. We propose that this M6PR pathway is most utilized in VZV infection and least utilized in HSV1 infection, with PRV's usage being closer to HSV1's usage. Supportive data from other VZV, PRV, and HSV1 laboratories about evidence for two egress pathways are included.

Varicella zoster virus productively infects human peripheral blood mononuclear cells to modulate expression of immunoinhibitory proteins and blocking PD-L1 enhances virus-specific CD8+ T cell effector function.

Varicella zoster virus (VZV) is a lymphotropic alpha-herpesvirinae subfamily member that produces varicella on primary infection and causes zoster, vascular disease and vision loss upon reactivation from latency. VZV-infected peripheral blood mononuclear cells (PBMCs) disseminate virus to distal organs to produce clinical disease. To assess immune evasion strategies elicited by VZV that may contribute to dissemination of infection, human PBMCs and VZV-specific CD8+ T cells (V-CD8+) were mock- or VZV-infected and analyzed for immunoinhibitory protein PD-1, PD-L1, PD-L2, CTLA-4, LAG-3 and TIM-3 expression using flow cytometry. All VZV-infected PBMCs (monocytes, NK, NKT, B cells, CD4+ and CD8+ T cells) and V-CD8+ showed significant elevations in PD-L1 expression compared to uninfected cells. VZV induced PD-L2 expression in B cells and V-CD8+. Only VZV-infected CD8+ T cells, NKT cells and V-CD8+ upregulated PD-1 expression, the immunoinhibitory receptor for PD-L1/PD-L2. VZV induced CTLA-4 expression only in V-CD8+ and no significant changes in LAG-3 or TIM-3 expression were observed in V-CD8+ or PBMC T cells. To test whether PD-L1, PD-L2 or CTLA-4 regulates V-CD8+ effector function, autologous PBMCs were VZV-infected and co-cultured with V-CD8+ cells in the presence of blocking antibodies against PD-L1, PD-L2 or CTLA-4; ELISAs revealed significant elevations in IFNγ only upon blocking of PD-L1. Together, these results identified additional immune cells that are permissive to VZV infection (monocytes, B cells and NKT cells); along with a novel mechanism for inhibiting CD8+ T cell effector function through induction of PD-L1 expression.

Herpesvirus encephalitis diagnosed by polymerase chain reaction at the National Institute of Neurology of Mexico.

The frequency of central nervous system infections due to herpesvirus have been studied in various populations; however, studies in Mexican mestizo patients are scant. This paper documents the frequency of herpesvirus encephalitis in Mexican mestizo patients from the National Institute of Neurology and Neurosurgery (NINN) of Mexico. To study the frequency of herpetic viral encephalitis at the NINN in the period from 2004 to 2009. We reviewed clinical records from patients with clinically suspected encephalitis; polymerase chain reaction assays were done for detection of herpesviruses in cerebrospinal fluid (CSF) samples. The total number of patients studied was 502; in 59 (12%), the diagnosis of herpetic encephalitis was confirmed by PCR-based testing of CSF. Of them, 21 (36%) were positive for herpes simplex virus type 1, 15 (25%) for Epstein-Barr virus, 10 (17%) for varicella zoster virus, 8 (14%) for cytomegalovirus, 3 (5%) for human herpesvirus 6, and 2 (3%) for herpes simplex virus 2. Our results show a varied frequency of viral encephalitis in mestizo patients due to herpesviruses in a tertiary neurological center and point out the importance of modern molecular technology to reach the etiological diagnosis in cases of encephalitis.

P2X7 receptor antagonist BBG inhibits endoplasmic reticulum stress and pyroptosis to alleviate postherpetic neuralgia.

Postherpetic neuralgia (PHN) is the most common complication of acute herpes zoster. The treatment of PHN remains a challenge for clinical pain management. The present study investigated the P2X7 receptor antagonist brilliant blue G (BBG) whether inhibits endoplasmic reticulum stress and pyroptosis (a necrotic form of cell death) and alleviates PHN. Varicella zoster virus (VZV)-infected CV-1 cells were used to induce PHN model. Mechanical paw withdrawal thresholds were measured using an ascending series of von Frey filaments. Immunohistochemistry was used to detect the expression of P2X7R in nerve tissues. Western blot was used to determine the expression of endoplasmic reticulum (ER) stress and pyroptosis-related molecules. The expression of IL-1ß and IL-18 in tissue homogenate was detected by ELISA. The PHN rat has the lower paw withdrawal threshold, but higher expression of P2X7 in nerve tissues. And, endoplasmic reticulum stress was activated and pyroptosis was increased in PHN rats. BBG can decrease pain thresholds and reduce ER stress and pyroptosis in PHN rats. In addition, ER stress activator tunicamycin (TM) can reverse the effect of BBG on the paw withdrawal thresholds, endoplasmic reticulum stress, and pyroptosis. Therefore, P2X7 receptor antagonist BBG alleviates PHN by activating ER stress and reducing pyroptosis.

A Case of Eosinophilic Pustular Folliculitis Associated With Herpes Zoster.

ABSTRACT: Patients with eosinophilic pustular folliculitis (EPF), a sterile eosinophilic infiltration of hair follicles, often present with papulopustules that tend to form annular plaques. Histopathologic examination revealed eosinophilic infiltration around the pilosebaceous units and eosinophilic microabscess formation. Although the pathogenesis of EPF is unknown, T-helper type 2 immune responses were suggested to be important based on their stimulating effect on the sebaceous glands. Here, we report the first case of EPF associated with herpes zoster, indicating that herpes zoster and EPF are correlated with T-helper type 2 immune responses.

Ischemic Cerebellar Stroke in a 4-Year-Old Boy After Chickenpox: An Atypical Vascular Involvement.

Cerebrovascular events in pediatric population are very rare. Up to 30% may result from varicella zoster (VZV) arteriopathy, usually as a delayed complication of varicella primary infection. The most typical pattern includes involvement of anterior brain circulation arteries, probably by VZV migration from the trigeminal ganglia. Strokes related with VZV usually have a good prognosis, but risk of recurrence is greater when compared to other stroke etiologies in this age group. We report the case of a 4-year-old boy, immunocompetent, who presented a basilar artery stenosis and a cerebellar stroke, an extremely rare presentation of VZV arteriopathy. The investigation workup and treatment are detailed, as the clinical and imaging follow-up after one year.

Recurrent Herpes Zoster Ophthalmicus in a Patient With a Novel Toll-Like Receptor 3 Variant Linked to Compromised Activation Capacity in Fibroblasts.

BACKGROUND: Herpes zoster ophthalmicus occurs primarily in elderly or immunocompromised individuals after reactivation of varicella zoster virus (VZV). Recurrences of zoster ophthalmicus are uncommon because the reactivation efficiently boosts anti-VZV immunity. A 28-year-old female presented to our clinic with a history of multiple recurrences of zoster ophthalmicus. METHODS: Whole-exome sequencing (WES), analyses of VZV T-cell immunity, and pathogen recognition receptor function in primary antigen-presenting cells (APCs) and fibroblasts were performed. RESULTS: Normal VZV-specific T-cell immunity and antibody response were detected. Whole-exome sequencing identified a heterozygous nonsynonymous variant (c.2324C > T) in the Toll-like receptor 3 (TLR3) gene resulting in formation of a premature stop-codon. This alteration could potentially undermine TLR3 signaling in a dominant-negative fashion. Therefore, we investigated TLR3 signaling responses in APCs and fibroblasts from the patient. The APCs responded efficiently to stimulation with TLR3 ligands, whereas the responses from the fibroblasts were compromised. CONCLUSIONS: We report a novel TLR3 variant associated with recurrent zoster ophthalmicus. Toll-like receptor 3 responses that were unaffected in APCs but diminished in fibroblasts are in line with previous reports linking TLR3 deficiency with herpes simplex virus encephalitis. Mechanisms involving compromised viral sensing in infected cells may thus be central to the described immunodeficiency.

Radiation therapy and the risk of herpes zoster in patients with cancer.

BACKGROUND: The role and impact of radiation therapy (RT) on the development of herpes zoster (HZ) has not been well studied. The objective of this study was to investigate the association between RT and HZ. METHODS: A propensity score-matched, retrospective cohort study was conducted using institutional cancer registry data and medical records from 2011 to 2015. The risk of developing HZ in the RT and non-RT groups was compared using a Cox proportional hazards model. Associations also were explored between the RT field and the anatomic location of HZ in patients who developed HZ after RT. The expected number of HZ events within the radiation field was calculated according to the RT received by each patient; then, this number was compared with the observed number of in-field events. RESULTS: Of 17,655 patients, propensity score matching yielded 4350 pairs; of these, 3891 pairs were eligible for comparison. The cumulative incidence of HZ in the RT group (vs the non-RT group) during the first 5 years after the index date was 2.1% (vs 0.7%) at 1 year, 3.0% (vs 1.0%) at 2 years, 3.4% (vs 1.3%) at 3 years, 4.1% vs 1.7% at 4 years, and 4.4% vs 1.8% at 5 years. The RT group showed a significantly higher risk of HZ than the non-RT group (hazard ratio, 2.59, 95% CI, 1.84-3.66). In the 120 patients who developed HZ after RT, HZ events were observed significantly more frequently within the RT field than expected (74 vs 43.8 events; P < .001). CONCLUSIONS: Patients with cancer who received RT showed a significantly higher risk of HZ, which was commonly observed within the radiation field.

Central nervous system infections produced by varicella zoster virus.

PURPOSE OF REVIEW: Varicella zoster virus (VZV) causes varicella, establishes latency, then reactivates to produce herpes zoster. VZV reactivation can also cause central nervous system (CNS) disease with or without rash. Herein, we review these CNS diseases, pathogenesis, diagnosis, and treatment. RECENT FINDINGS: The most common CNS manifestation of VZV infection is vasculopathy that presents as headache, cognitive decline, and/or focal neurological deficits. VZV vasculopathy has also been associated with cerebral amyloid angiopathy and moyamoya syndrome. Rarely, VZV will produce a meningitis, encephalitis, cerebellitis, and myelopathy. Pathogenic mechanisms include direct VZV infection of affected tissue, persistent inflammation, and/or virus-induced hypercoagulability. Diagnosis is confirmed by the temporal association of rash to disease onset, intrathecal synthesis of anti-VZV antibodies, and/or the presence of VZV DNA in CSF. Most cases respond to intravenous acyclovir with corticosteroids. SUMMARY: VZV produces a wide spectrum of CNS disorders that may be missed as some cases do not have an associated rash or a CSF pleocytosis. Clinicians must be vigilant in including VZV in their differential diagnosis of CNS infections as VZV is a ubiquitous pathogen; importantly, VZV CNS infections are treatable with intravenous acyclovir therapy and corticosteroids.

Progeny Varicella-Zoster Virus Capsids Exit the Nucleus but Never Undergo Secondary Envelopment during Autophagic Flux Inhibition by Bafilomycin A1.

Varicella-zoster virus (VZV) is an alphaherpesvirus that lacks the herpesviral neurovirulence protein ICP34.5. The underlying hypothesis of this project was that inhibitors of autophagy reduce VZV infectivity. We selected the vacuolar proton ATPase inhibitor bafilomycin A1 for analysis because of its well-known antiautophagy property of impeding acidification during the late stage of autophagic flux. We documented that bafilomycin treatment from 48 to 72 h postinfection lowered VZV titers substantially (P ≤ 0.008). Because we were unable to define the site of the block in the infectious cycle by confocal microscopy, we turned to electron microscopy. Capsids were observed in the nucleus, in the perinuclear space, and in the cytoplasm adjacent to Golgi apparatus vesicles. Many of the capsids had an aberrant appearance, as has been observed previously in infections not treated with bafilomycin. In contrast to prior untreated infections, however, secondary envelopment of capsids was not seen in the trans-Golgi network, nor were prototypical enveloped particles with capsids (virions) seen in cytoplasmic vesicles after bafilomycin treatment. Instead, multiple particles with varying diameters without capsids (light particles) were seen in large virus assembly compartments near the disorganized Golgi apparatus. Bafilomycin treatment also led to increased numbers of multivesicular bodies in the cytoplasm, some of which contained remnants of the Golgi apparatus. In summary, we have defined a previously unrecognized property of bafilomycin whereby it disrupted the site of secondary envelopment of VZV capsids by altering the pH of the trans-Golgi network and thereby preventing the correct formation of virus assembly compartments.IMPORTANCE This study of VZV assembly in the presence of bafilomycin A1 emphasizes the importance of the Golgi apparatus/trans-Golgi network as a platform in the alphaherpesvirus life cycle. We have previously shown that VZV induces levels of autophagy far above the basal levels of autophagy in human skin, a major site of VZV assembly. The current study documented that bafilomycin treatment led to impaired assembly of VZV capsids after primary envelopment/de-envelopment but before secondary reenvelopment. This VZV study also complemented prior herpes simplex virus 1 and pseudorabies virus studies investigating two other inhibitors of endoplasmic reticulum (ER)/Golgi apparatus function: brefeldin A and monensin. Studies with porcine herpesvirus demonstrated that primary enveloped particles accumulated in the perinuclear space in the presence of brefeldin A, while studies with herpes simplex virus 1 documented an impaired secondary assembly of enveloped viral particles in the presence of monensin.

Varicella zoster virus productively infects human natural killer cells and manipulates phenotype.

Varicella zoster virus (VZV) is a ubiquitous human alphaherpesvirus, responsible for varicella upon primary infection and herpes zoster following reactivation from latency. To establish lifelong infection, VZV employs strategies to evade and manipulate the immune system to its advantage in disseminating virus. As innate lymphocytes, natural killer (NK) cells are part of the early immune response to infection, and have been implicated in controlling VZV infection in patients. Understanding of how VZV directly interacts with NK cells, however, has not been investigated in detail. In this study, we provide the first evidence that VZV is capable of infecting human NK cells from peripheral blood in vitro. VZV infection of NK cells is productive, supporting the full kinetic cascade of viral gene expression and producing new infectious virus which was transmitted to epithelial cells in culture. We determined by flow cytometry that NK cell infection with VZV was not only preferential for the mature CD56dim NK cell subset, but also drove acquisition of the terminally-differentiated maturity marker CD57. Interpretation of high dimensional flow cytometry data with tSNE analysis revealed that culture of NK cells with VZV also induced a potent loss of expression of the low-affinity IgG Fc receptor CD16 on the cell surface. Notably, VZV infection of NK cells upregulated surface expression of chemokine receptors associated with trafficking to the skin -a crucial site in VZV disease where highly infectious lesions develop. We demonstrate that VZV actively manipulates the NK cell phenotype through productive infection, and propose a potential role for NK cells in VZV pathogenesis.

Elevated serum substance P during simian varicella virus infection in rhesus macaques: implications for chronic inflammation and adverse cerebrovascular events.

Varicella and zoster, produced by varicella-zoster virus (VZV), are associated with an increased risk of stroke that may be due to persistent inflammation and hypercoagulability. Because substance P is associated with inflammation, hypercoagulability, and atherosclerotic plaque rupture that may contribute to increased stroke risk after VZV infection, we measured serum substance P in simian varicella virus-infected rhesus macaques. We found significantly increased and persistent serum substance P concentrations during varicella and zoster compared with pre-inoculation, supporting the hypothesis that VZV-induced increases in serum substance P may contribute to increased stroke risk associated with VZV infection.

Serum and cerebrospinal fluid neurofilament light chain in patients with central nervous system infections caused by varicella-zoster virus.

Varicella-zoster virus (VZV) is a common cause of viral central nervous system (CNS) infection, and patients may suffer from severe neurological sequelae. The biomarker neurofilament light chain (NFL) is used for assessment of neuronal damage and is normally measured in cerebrospinal fluid (CSF). Novel methods have given the possibility to measure NFL in serum instead, which could be a convenient tool to estimate severity of disease and prognosis in VZV CNS infections. Here, we investigate the correlation of serum and CSF NFL in patients with VZV CNS infection and the association of NFL levels in serum and CSF with different VZV CNS entities. NFL in serum and CSF was measured in 61 patients who were retrospectively identified with neurological symptoms and VZV DNA in CSF detected by PCR. Thirty-three herpes zoster patients and 40 healthy blood donors served as control groups. NFL levels in serum and CSF correlated strongly in the patients with VZV CNS infection. Encephalitis was associated with significantly higher levels of NFL in both serum and CSF compared with meningitis and Ramsay Hunt syndrome. Surprisingly, herpes zoster controls had very high serum NFL levels, comparable with those shown in encephalitis patients. We show that analysis of serum NFL can be used instead of CSF NFL for estimation of neuronal injury in patients with VZV CNS infection. However, high levels of serum NFL also in patients with herpes zoster, without signs of CNS involvement, may complicate the interpretation.

Acute zoster plasma contains elevated amyloid, correlating with Aß42 and amylin levels, and is amyloidogenic.

Herpes zoster is associated with an increased dementia and neovascular macular degeneration risk and a decline in glycemic control in diabetes mellitus. Because amyloid is present and pathogenic in these diseases, we quantified amyloid, Aß40, Aß42, and amylin in 14 zoster and 10 control plasmas. Compared with controls, zoster plasma had significantly elevated amyloid that correlated with Aß42 and amylin levels and increased amyloid aggregation with addition of exogenous Aß42 or amylin. These results suggest that zoster plasma contains factor(s) that promotes aggregation of amyloidogenic peptides, potentially contributing to the toxic amyloid burden and explaining accelerated disease progression following zoster.

Determinants of neurological syndromes caused by varicella zoster virus (VZV).

Varicella zoster virus (VZV) is a pathogenic human herpes virus which causes varicella as a primary infection, following which it becomes latent in peripheral autonomic, sensory, and cranial nerve ganglionic neurons from where it may reactivate after decades to cause herpes zoster. VZV reactivation may also cause a wide spectrum of neurological syndromes, in particular, acute encephalitis and vasculopathy. While there is potentially a large number of coding viral mutations that might predispose certain individuals to VZV infections, in practice, a variety of host factors are the main determinants of VZV infection, both disseminated and specifically affecting the nervous system. Host factors include increasing age with diminished cell-mediated immunity to VZV, several primary immunodeficiency syndromes, secondary immunodeficiency syndromes, and drug-induced immunosuppression. In some cases, the molecular immunological basis underlying the increased risk of VZV infections has been defined, in particular, the role of POL III mutations, but in other cases, the mechanisms have yet to be determined. The role of immunization in immunosuppressed individuals as well as its possible efficacy in preventing both generalized and CNS-specific infections will require further investigation to clarify in such patients.

Clinical spectrum and prognosis of neurological complications of reactivated varicella-zoster infection: the role of immunosuppression.

Immunosuppressed patients are at higher risk for developing herpes zoster (HZ), and neurological complications are frequent in them. However, the influence of immunosuppression (IS) on the severity and prognosis of neurological complications of varicella-zoster virus (VZV) reactivation is unknown. We studied retrospectively patients with neurological complications due to VZV reactivation who attended our hospital between 2004 and 2019. We aimed to assess the clinical spectrum, potential prognostic factors, and the influence of the immune status on the severity of neurological symptoms. A total of 98 patients were included (40% had IS). Fifty-five patients (56%) had cranial neuropathies which included Ramsay-Hunt syndrome (36 patients) and cranial multineuritis (23 patients). Twenty-one patients developed encephalitis (21%). Other diagnosis included radiculopathies, meningitis, vasculitis, or myelitis (15, 10, 6, and 4 patients, respectively). Mortality was low (3%). At follow-up, 24% of patients had persistent symptoms although these were usually mild. IS was associated with severity (defined as a modified Rankin scale greater than 2) (odds ratio, 4.23; 95% confidence interval, 1.74-10.27), but not with prognosis. Shorter latency between HZ and neurologic symptoms was the only factor associated with an unfavorable course (death or sequelae) (odds ratio, 0.82; 95% confidence interval, 0.71-0.95). In conclusion, the clinical spectrum of neurological complications in VZV reactivation is wide. Mortality was low and sequelae were mild. The presence of IS may play a role on the severity of neurological symptoms, and a shorter time between HZ and the onset of neurological symptoms appears to be a negative prognostic factor.