Genetic Variants and Immune Responses in a Cohort of Patients With Varicella Zoster Virus Encephalitis.

BACKGROUND: Infection with varicella zoster virus (VZV) may involve different central nervous system (CNS) manifestations, including meningitis, encephalitis, and vasculitis. In cases in which otherwise healthy individuals are affected, an inborn error of immunity may underlie increased susceptibility or severity of infection. METHODS: We collected a cohort of 17 adults who experienced VZV encephalitis and performed whole exome sequencing. Patient peripheral blood mononuclear cells were infected with VZV, and innate antiviral interferon (IFN) and cytokine responses as well as viral replication were evaluated. Data were analyzed by Mann-Whitney U test. RESULTS: We identified a total of 21 different potentially disease-causing variants in a total of 13 of the 17 patients included. These gene variants were within 2 major functional clusters: (1) innate viral sensors and immune pathways and (2) autophagy pathways. Antiviral IFN and cytokine responses were abnormal in the majority of patients, whereas viral replication was increased in only 2 of 17 patients. CONCLUSIONS: This study identifies a list of variants of pathogenic potential, which may serve as a platform for generating hypotheses for future studies addressing genetic and immunological factors associated with susceptibility to VZV encephalitis. These data, taken together, suggest that disturbances in innate sensing and autophagy pathways may predispose to VZV encephalitis.

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.

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.

The link between varicella and immune system: which children will develop acute cerebellitis?

INTRODUCTION: Varicella may complicate with cerebellitis in previously healthy children, requiring hospitalization. Aim of our study was to define whether children who experienced varicella cerebellitis have a normal immune system. METHODS: Patients over 3 years of age admitted at Bambino Gesù Children from January 2006 till June 2016 for cerebellitis in varicella were asked to participate to the follow-up study. The immune status was evaluated clinically and by laboratory investigations. RESULTS: Twenty-five patients were included in the study. At follow up, at least one immunological alteration was detected in 80% of patients. To avoid bias due to possible effects of the recent disease, we separately analyzed patients who had the follow-up control at least 1 year (Group 1) or between 1 month and 1 year (Group 2) after the hospitalization for acute varicella cerebellitis. The results were similar in both groups with immunological alterations detected in 84,6 and 75% of the patients, respectively. CONCLUSIONS: Our preliminary results indicate that sub-clinical immunological defects may correlate to cerebellitis in varicella.

Varicella zoster virus (VZV) oculomeningoencephalomyeloradiculitis: a previously undescribed constellation.

A 53-year-old immunocompromised woman developed acute left eye blindness and paraparesis suspected to be due to neuromyelitis optica (NMO). During treatment for NMO, right eye blindness and progressive multiple cranial neuropathies developed. Cerebrospinal fluid polymerase chain reaction (PCR) revealed Varicella zoster virus (VZV). This case emphasizes the importance of considering VZV in individuals, particularly the immunocompromised, presenting with a constellation of neurological signs and symptoms, even in the absence of rash.

Characterization of Virus-specific Immune Response During Varicella Zoster Virus Encephalitis in a Young Adult.

An immunocompetent adult received corticosteroids for chest pain, which later was clinically found to be herpes zoster (HZ). She developed severe disease and rapid viral dissemination that elicited an exceptionally strong varicella zoster virus-specific B-cell and CD8 T-cell response. Clinicians should consider atypical HZ presentation prior to corticosteroid administration.

RNA Polymerase III as a Gatekeeper to Prevent Severe VZV Infections.

In most individuals, varicella zoster virus (VZV) causes varicella upon primary infection and zoster during reactivation. However, in a subset of individuals, VZV may cause severe disease, including encephalitis. Host genetics is believed to be the main determinant of exacerbated disease manifestations. Recent studies have demonstrated that defects in the DNA sensor RNA polymerase III (POL III) confer selective increased susceptibility to VZV infection, thus providing fundamental new insight into VZV immunity. Here we describe the roles of POL III in housekeeping and immune surveillance during VZV infection. We present the latest knowledge on the role of POL III in VZV infection and discuss outstanding questions related to the role of POL III in VZV immunity, and how this insight can be translated into clinical medicine.

Progressive hippocampal sclerosis after viral encephalitis: Potential role of NMDA receptor antibodies.

PURPOSE: Survivors of viral encephalitis can develop refractory epilepsy and hippocampal sclerosis. Both the initial infectious insult and the secondary effects of recurrent seizures have been implicated in chronic disease progression. Recently, post-infectious autoimmunity, involved in acute relapses, has also been proposed as a pathomechanism for chronic disease progression. Our case series suggests a potential role of antibodies against the N-methyl-d-aspartate receptor (NMDAR) in chronic inflammatory disease beyond acute manifestations. METHODS: Retrospective chart review of four patients with epilepsy, hippocampal sclerosis following viral encephalitis and NMDAR-antibodies in CSF. RESULTS: The four patients were female, developed hippocampal sclerosis (in 3/4 in a step-wise progression) after Herpes simplex or Varicella zoster virus encephalitis and harboured immunoglobulin G antibodies against the NMDAR in their CSF. Two patients were treated with short-term immunosuppression but did not benefit. CONCLUSION: This case series presents the first tentative evidence in support of chronic autoimmune inflammation driving disease progression after viral encephalitis beyond the known acute immune-mediated relapses. The anecdotal nature of the data does not, however, permit conclusive judgement on causality. Should our findings be replicated in larger cohorts, the treatment of post-infectious epilepsy could potentially be expanded to include immunosuppressive strategies in antibody-positive cases.

Defensive Perimeter in the Central Nervous System: Predominance of Astrocytes and Astrogliosis during Recovery from Varicella-Zoster Virus Encephalitis.

UNLABELLED: Varicella-zoster virus (VZV) is a highly neurotropic virus that can cause infections in both the peripheral nervous system and the central nervous system. Several studies of VZV reactivation in the peripheral nervous system (herpes zoster) have been published, while exceedingly few investigations have been carried out in a human brain. Notably, there is no animal model for VZV infection of the central nervous system. In this report, we characterized the cellular environment in the temporal lobe of a human subject who recovered from focal VZV encephalitis. The approach included not only VZV DNA/RNA analyses but also a delineation of infected cell types (neurons, microglia, oligodendrocytes, and astrocytes). The average VZV genome copy number per cell was 5. Several VZV regulatory and structural gene transcripts and products were detected. When colocalization studies were performed to determine which cell types harbored the viral proteins, the majority of infected cells were astrocytes, including aggregates of astrocytes. Evidence of syncytium formation within the aggregates included the continuity of cytoplasm positive for the VZV glycoprotein H (gH) fusion-complex protein within a cellular profile with as many as 80 distinct nuclei. As with other causes of brain injury, these results suggested that astrocytes likely formed a defensive perimeter around foci of VZV infection (astrogliosis). Because of the rarity of brain samples from living humans with VZV encephalitis, we compared our VZV results with those found in a rat encephalitis model following infection with the closely related pseudorabies virus and observed similar perimeters of gliosis. IMPORTANCE: Investigations of VZV-infected human brain from living immunocompetent human subjects are exceedingly rare. Therefore, much of our knowledge of VZV neuropathogenesis is gained from studies of VZV-infected brains obtained at autopsy from immunocompromised patients. These are not optimal samples with which to investigate a response by a human host to VZV infection. In this report, we examined both flash-frozen and paraffin-embedded formalin-fixed brain tissue of an otherwise healthy young male with focal VZV encephalitis, most likely acquired from VZV reactivation in the trigeminal ganglion. Of note, the cellular response to VZV infection mimicked the response to other causes of trauma to the brain, namely, an ingress of astrocytes and astrogliosis around an infectious focus. Many of the astrocytes themselves were infected; astrocytes aggregated in clusters. We postulate that astrogliosis represents a successful defense mechanism by an immunocompetent human host to eliminate VZV reactivation within neurons.

Varicella-zoster virus encephalomyelitis with a prominent demyelinating component.

The histopathologic presentation of varicella-zoster virus (VZV) infection of the central nervous system is varied and is not well understood. Here we report a case of VZV encephalomyelitis with prominent demyelinating pathology in a patient with a history of follicular lymphoma treated with allogeneic stem cell transplantation. The patient presented with waxing and waning bilateral limb weakness and mental status changes. MRI showed leptomeningeal, peripheral spinal cord and periventricular cerebral white matter lesions in the brain, and polymerase chain reaction on cerebrospinal fluid detected VZV DNA. The patient expired from developing atrial fibrillation that rapidly progressed to ventricular fibrillation 10 days after admission to our hospital. Autopsy revealed macrophage-rich areas of demyelination in the spinal cord and cerebrum with relative preservation of axons associated with inclusion bodies and positive immunostaining for VZV. This case represents a rare example of VZV encephalomyelitis presenting with a predominantly demyelinating, "multiple sclerosis-like" pathology. The clinical and histopathologic findings and relevant literature are presented and discussed.

Psychiatric aspects of herpes simplex encephalitis, tick-borne encephalitis and herpes zoster encephalitis among immunocompetent patients.

The psychopathological symptoms occurring in the course of diseases associated with infections are often initially isolated and non-characteristic, and may cause diagnostic difficulties. Moreover, such disorders tend to be less responsive to psychiatric management. Among possible causes such as trauma, neoplasm and vascular changes, inflammatory changes of the brain as a result of a viral infection should also be considered. There were 452 registered cases of viral encephalitis in Poland in 2010, and although not very prevalent they remain a severe and life-threatening condition. What is more, the frequently occurring neurological and psychiatric complications of viral encephalitis often result in permanent disabilities, causing a significant decrease in the quality of life. This article presents the three types of encephalitis that are most prevalent among immunocompetent patients in Poland, i.e. herpes simplex encephalitis (HSE), tick-borne encephalitis (TBE) and herpes zoster encephalitis (HZE). The psychopathology of the acute phase of the infection, the residual symptoms, features apparent in imaging studies and some neuropathological aspects are also presented. The paper also focuses on psychiatric aspects of the diagnostics and treatment of the described conditions. The clinical pictures of these infections are quite specific, although they cover a wide range of symptoms, and these characteristic features are described. The aim of this review is also to show the significance of thorough diagnostics and a multidisciplinary approach to patients with viral CNS infections.

Fatal wild-type varicella-zoster virus encephalitis without a rash in a vaccinated child.

Encephalitis associated with varicella-zoster virus, rare among children in the varicella vaccine era, has generally been associated with a rash. We report fatal wild-type varicella-zoster virus encephalitis without a rash in a child who had received 1 dose of varicella vaccine. Varicella-zoster virus encephalitis should be considered in the differential diagnosis for children presenting with acute neurologic symptoms, even vaccine recipients.

Varicella-zoster virus (VZV) glycoprotein E is a serological antigen for detection of intrathecal antibodies to VZV in central nervous system infections, without cross-reaction to herpes simplex virus 1.

Herpes simplex virus 1 (HSV-1) and varicella-zoster virus (VZV) cause serious central nervous system (CNS) diseases that are diagnosed with PCR using samples of cerebrospinal fluid (CSF) and, during later stages of such infections, with assays of intrathecal IgG antibody production. However, serological diagnoses have been hampered by cross-reactions between HSV-1 and VZV IgG antibodies and are commonly reported in patients with herpes simplex encephalitis (HSE). In this study we have evaluated VZV glycoprotein E (gE) as a new antigen for serological diagnosis of VZV-induced CNS infections. Paired samples of CSF and serum from 29 patients with clinical diagnosis of VZV CNS infection (n = 15) or HSE (n = 14), all confirmed by PCR, were analyzed. VZV gE and whole VZV were compared as antigens in enzyme-linked immunosorbent assays (ELISAs) for serological assays in which the CSF/serum sample pairs were diluted to identical IgG concentrations. With the gE antigen, none of the HSE patients showed intrathecal IgG antibodies against VZV, compared to those shown by 11/14 patients using whole-VZV antigen (P < 0.001). In the patients with VZV infections, significantly higher CSF/serum optical density (OD) ratios were found in the VZV patients using the VZV gE antigen compared to those found using the whole-VZV antigen (P = 0.001). These results show that gE is a sensitive antigen for serological diagnosis of VZV infections in the CNS and that this antigen was devoid of cross-reactivity to HSV-1 IgG in patients with HSE. We therefore propose that VZV gE can be used for serological discrimination of CNS infections caused by VZV and HSV-1.

Recurrent varicella zoster virus myelopathy.

Myelopathy is an uncommon complication of VZV infection and may develop in the absence of rash. We report the rare recurrence of myelopathy in an immunocompetent adult who initially developed myelopathy after ophthalmic-distribution zoster. Recurrent myelopathy two years later caused by VZV was verified by the presence of new-onset clinical symptoms and signs consistent with myelopathy, new lesions in the spinal cord detected by MRI, and evidence of intrathecal synthesis of anti-VZV IgG antibody in CSF. After virological verification and antiviral therapy, myelopathy did not recur and anti-VZV IgG antibody could not be detected in CSF. In contrast to earlier cases of recurrent VZV myelopathy in immunocompetent adults that developed weeks to months after the first episode of myelopathy, this is the first instance of recurrence years later.

Varicella zoster virus meningo-encephalo-myelitis in an immunocompetent patient.

OBJECTIVE: To describe clinical, MRI and cerebrospinal fluid (CSF) features of a varicella zoster virus (VZV) related meningo-encephalo-myelitis (MEM) without rash in an immunocompetent female. PATIENT: An 85 year old immunocompetent woman with mild hyperthermia and acute, severe MEM. INTERVENTION: Serum antibodies and CSF PCR were searched for several viruses. Brain and spinal cord MRI were performed. Immunological profile. TREATMENTS: i.v. acyclovir 30 mg/kg/day; i.v. 6-MP 125 mg/day. RESULTS: Marked CSF lymphomonocytic pleocytosis, blood-brainbarrier damage, and PCR detection of 3.05 X 10 6 copies of VZV DNA. MRI revealed lesions of the meninges, brain and spinal cord. No evidence of immunosuppression. CONCLUSION: We highlight the importance of considering the possibility of VZV related MEM, even in immunocompetent patients. We also provide a MRI description of VZV related multifocal myelitis, not previously available. As supported by other reports, we underline the necessity of a prompt therapeutic intervention in this life-threatening condition.

Atypical presentation of varicella-zoster virus encephalitis in an immunocompetent adult.

BACKGROUND: Varicella-zoster virus encephalitis is uncommon, but not rare, in immunocompetent adults. Typically, patients develop stroke with hemiplegia caused by large vessel vasculopathy days to weeks after herpes zoster ophthalmicus. METHOD: A previously healthy 66-year-old man developed obtundation deteriorating to coma within 24 hours. He had lymphocytic meningitis and multiple bilateral edematous and hemorrhagic lesions predominantly in the white matter, and intraventricular and subarachnoid hemorrhage. Treatment with acyclovir and dexamethasone was readily administered. The diagnosis of varicella-zoster virus encephalitis was confirmed by polymerase chain reaction analysis of the cerebrospinal fluid. No zosteriform rash preceded or followed encephalitis. Two years later, the patient is in good health, and no relapse or sign of immunosuppression has been reported. CONCLUSION: This is a case of varicella-zoster virus encephalitis in an immunocompetent patient presenting without typical rash and with clinicoradiologic features of multifocal encephalitis, which characterize immunosuppression.