Immune evasion as a pathogenic mechanism of varicella zoster virus

'Synthesis, antiviral activity, molecular docking, and molecular dynamics studies of ethoxy phthalimide pyrazole derivatives against Cytomegalovirus and Varicella-Zoster virus: potential consequences and strategies for developing new antiviral treatments'

Substituted ethoxy phthalimide pyrazole derivatives (6a-e) have been produced using a one-pot synthesis technique. Spectral analysis was used to establish the molecular structure of the synthesized compounds, and they were examined in silico and in vitro for their ability to bind to and inhibit replication of the AD-169 strain, the Davis strain of CMV, the OKA strain and the 07/1 strain of Varicella-Zoster virus (VZV). Molecular Docking was used to estimate the binding mechanism and energy of compounds 4, 6a-e to their respective target proteins, thymidine kinase (TK), Varicella-Zoster protease (VZP) of VZV and tegument protein pp71 (TPpp71) of Cytomegalovirus (CMV). The MIC50 and EC50 were utilized to evaluate the antiviral and cytotoxic activities of test compounds in human embryonic lung (HEL) cells against the two reference medicines, Ganciclovir and Acyclovir. The chemicals studied showed a high affinity for binding sites and near binding sites of target proteins by generating H-bonds, carbon-hydrogen bonds, π-anion, π-sulfur, π-sigma, alkyl and π-alkyl interactions. All of the test compounds (6a-e) had higher binding energy than the standard medications. The ADME/T data suggests that these potential inhibitors are less toxic. Drug-protein complexes are structurally compact and demonstrate minimal conformational change in molecular dynamics (MDs) simulations, indicating stability and stiffness. MM-PBSA and post-simulation analysis can predict lead compound active cavity binding stability. By inhibiting multitargeted proteins, these synthetic compounds may improve antiviral therapy. Our research suggests that these unique synthesized chemicals may be useful and accessible adjuvant antiviral therapy for Varicella Zoster and CMV. HighlightsTwo components synthesis of substituted ethoxy phthalimide pyrazole derivatives (6a-e).Tested compounds (6a-e) have antiviral and cytotoxicity activity against CMV and Varicella-Zoster virus (VZV) in HEL cells.Compounds bind to TK, Varicella-Zoster protease (VZP) of VZV, and modeled TPpp71 of Cytomegalovirus (CMV).In comparison to reference drugs, compounds have strong binding free energy and interactions with VZV and CMV protein complexes.The RMSD, RMSF, Rg, residual correlative motion (RCM), No. of hydrogen bonds, protein secondary structure content, per-residue protein secondary structure and MM/PBSA energy calculated for the selected compound with thymidine kinase (TK), VZP of VZV, and modeled tegument protein pp71 (TPpp71) of CMV through MD simulation studies for 50 ns.In comparison to the two reference drugs, ligands/compounds were found to meet the Lipinski rule of five and to have strong biological activity.Communicated by Ramaswamy H. Sarma.

Varicella Zoster Virus infects mucosal associated Invariant T cells

Introduction

Mucosal Associated Invariant T (MAIT) cells are innate-like T cells that respond to conserved pathogen-derived vitamin B metabolites presented by the MHC class I related-1 molecule (MR1) antigen presentation pathway. Whilst viruses do not synthesize these metabolites, we have reported that varicella zoster virus (VZV) profoundly suppresses MR1 expression, implicating this virus in manipulation of the MR1:MAIT cell axis. During primary infection, the lymphotropism of VZV is likely to be instrumental in hematogenous dissemination of virus to gain access to cutaneous sites where it clinically manifests as varicella (chickenpox). However, MAIT cells, which are found in the blood and at mucosal and other organ sites, have yet to be examined in the context of VZV infection. The goal of this study was to examine any direct impact of VZV on MAIT cells.

Methods

Using flow cytometry, we interrogated whether primary blood derived MAIT cells are permissive to infection by VZV whilst further analysing differential levels of infection between various MAIT cell subpopulations. Changes in cell surface extravasation, skin homing, activation and proliferation markers after VZV infection of MAIT cells was also assessed via flow cytometry. Finally the capacity of MAIT cells to transfer infectious virus was tested through an infectious center assay and imaged via fluorescence microscopy.

Results

We identify primary blood-derived MAIT cells as being permissive to VZV infection. A consequence of VZV infection of MAIT cells was their capacity to transfer infectious virus to other permissive cells, consistent with MAIT cells supporting productive infection. When subgrouping MAIT cells by their co- expression of a variety cell surface markers, there was a higher proportion of VZV infected MAIT cells co-expressing CD4+ and CD4+/CD8+ MAIT cells compared to the more phenotypically dominant CD8+ MAIT cells, whereas infection was not associated with differences in co-expression of CD56 (MAIT cell subset with enhanced responsiveness to innate cytokine stimulation), CD27 (co-stimulatory) or PD-1 (immune checkpoint). Infected MAIT cells retained high expression of CCR2, CCR5, CCR6, CLA and CCR4, indicating a potentially intact capacity for transendothelial migration, extravasation and trafficking to skin sites. Infected MAIT cells also displayed increased expression of CD69 (early activation) and CD71 (proliferation) markers.

Discussion

These data identify MAIT cells as being permissive to VZV infection and identify impacts of such infection on co- expressed functional markers.

Association between Meteorological Factors and Outpatient Visits for Herpes Zoster in Hefei, China: A Time-Series Analysis

This study sought to investigate the relationship between meteorological factors and outpatient visits for herpes zoster. In this time-series analysis, we used data from two major hospitals in Hefei, collected between 2015 and 2019, to evaluate the impact of meteorological factors on the risk of herpes zoster. After controlling for confounders, we adopted a distributed lag nonlinear model to probe the relationship between meteorological factors and outpatient visits for herpes zoster. The analysis was stratified according to age (<40 years, ≥40 years) and sex (male, female). A total of 43,547 cases of herpes zoster were reported, and compared with the median value, a high temperature and high relative humidity had a significant risk effect on the incidence of herpes zoster. The maximum harmful effect of high temperature on herpes zoster occurred on the lag0 (RR: 1.027, 95% CI: 1.002-1.053) and further declined over the following days. The cumulative effect increased with the extension of lag days, and the cumulative RR was the largest on the sixth day of lag (RR1.031, 95% CI: 1.006-1.056) when the relative humidity was 85.7% (77.0% as the reference). The stratified analysis results reveal that females and the elderly (≥40 years) were more susceptible to temperature and relative humidity. This study shows that high-temperatures may lead to herpes zoster, indicating that those infected with varicella zoster virus need to take measures over the course of several days when not exposed to the best appropriate temperature conditions.

JAK kinase inhibitors and varicella zoster virus infection in patients with rheumatoid arthritis. Systematic review of the literature

OBJECTIVES

JAK kinase inhibitors (JAKi) are a new therapeutic option in the treatment of rheumatoid arthritis, but they are not without risks, especially the incidence of herpes zoster (HZ).

MATERIAL AND METHODS

Systematic literature review that evaluates the incidence of HZ published in the clinical trials of the different JAK is marketed or under study.

RESULTS

The HZ rates ranged between 1.51 and 20.22. The results were expressed mainly as a percentage of events. The most recent studies better categorized the incidence of HZ and its severity.

CONCLUSION

JAK is are associated with an increased risk of HZ. Although the HZ rates of the selective JAK1 JAK is are lower, more studies are needed to confirm these results.

The Biology of Varicella-Zoster Virus Replication in the Skin

The replication of varicella-zoster virus (VZV) in skin is critical to its pathogenesis and spread. Primary infection causes chickenpox, which is characterised by centrally distributed skin blistering lesions that are rich in infectious virus. Cell-free virus in the cutaneous blistering lesions not only spreads to cause further cases, but infects sensory nerve endings, leading to the establishment of lifelong latency in sensory and autonomic ganglia. The reactivation of virus to cause herpes zoster is again characterised by localised painful skin blistering rash containing infectious virus. The development of in vitro and in vivo models of VZV skin replication has revealed aspects of VZV replication and pathogenesis in this important target organ and improved our understanding of the vaccine strain vOKa attenuation. In this review, we outline the current knowledge on VZV interaction with host signalling pathways, the viral association with proteins associated with epidermal terminal differentiation, and how these interconnect with the VZV life cycle to facilitate viral replication and shedding.

A systematic review and meta-analysis of infection risk with small molecule JAK inhibitors in rheumatoid arthritis

OBJECTIVES

To evaluate the risk of serious infection (SI) and herpes zoster (HZ) in rheumatoid arthritis patients receiving JAK inhibitors.

METHODS

We conducted a systematic literature review and meta-analysis of phase II and III randomized controlled trials of tofacitinib (5 mg bid), baricitinib (4 mg od) and upadacitinib (15 mg od). Patient-exposure years were calculated. A per-protocol analysis was applied, incorporating follow-up time from patients randomized to placebo who cross into the treatment arm. Pooled incidence rates per 100 person-years of SI and HZ were calculated. Incidence rate ratios (IRRs) of drug vs placebo were compared using a meta-synthesis approach.

RESULTS

Twenty-one studies were included in the meta-analysis; 11 tofacitinib (5888 patients), six baricitinib (3520 patients) and four upadacitinib studies (1736 patients). For SI, the incidence rates were 1.97 (95% CI: 1.41, 2.68), 3.16 (95% CI: 2.07, 4.63) and 3.02 (95% CI: 0.98, 7.04), respectively. The IRRs comparing treatment arm to placebo were statistically non-significant: 1.22 (95% CI: 0.60, 2.45), 0.80 (95% CI: 0.46, 1.38) and 1.14 (95% CI: 0.24, 5.43), respectively. For HZ, the incidence rates were 2.51 (95% CI: 1.87, 3.30), 3.16 (95% CI: 2.07, 4.63) and 2.41 (95% CI: 0.66, 6.18), respectively. The IRR of HZ comparing baricitinib with placebo was 2.86 (95% CI: 1.26, 6.50). Non-significant IRRs were seen with tofacitinib and upadacitinib: 1.38 (95% CI: 0.66, 2.88) and 0.78 (95% CI: 0.19, 3.22), respectively. Indicator opportunistic infections excluding HZ were too rare to provide meaningful incidence rates.

CONCLUSION

The absolute SI rates were low. However across the JAK inhibitors, the incidence of HZ is higher than expected for the population (3.23 per 100 patient-years). While the risk was numerically greatest with baricitinib, indirect comparisons between the drugs did not demonstrate any significant difference in risk.

SYSTEMATIC REVIEW REGISTRATION NUMBER

Prospero 2017 CRD4201707879.

Indicator opportunistic infections after biological treatment in rheumatoid arthritis, 10 years follow-up in a real-world setting

Background:

This research describes the incidence and factors associated with opportunistic infections in rheumatoid arthritis (RA) patients treated with biological disease-modifying antirheumatic drugs (bDMARDs).

Methods:

A retrospective longitudinal study was carried out from 2007 to 2018. We included RA patients treated with a tumor necrosis factor (TNF)-targeted bDMARD or non-TNF-targeted bDMARD from the start of bDMARDs. An independent variable was the development of an indicator of opportunistic infection after biological (IOIb) treatment. Secondary variables included sociodemographic, clinical, and treatments. We used survival techniques to estimate the incidence of IOIb, per 1000 patient-years (95% CI). We performed a Cox multivariate regression analysis model to compare the risk of IOIb. Results were expressed as a hazard ratio (HR).

Results:

A total of 441 RA patients were included, that started 761 different courses of bDMARDs. A total of 81% were women with a mean age at first bDMARD of 57.3 ± 14 years. A total of 71.3% of the courses were TNF-targeted bDMARDs and 28.7% were non-TNF-targeted bDMARDs. There were 37 IOIb (25 viral, 6 fungal, 5 bacterial, 1 parasitic). Nine of these required hospitalization and one died. The global incidence of IOIb was 23.2 (16.8–32). TNF-targeted bDMARDs had 25 IOIb, incidence 20.5 (13.9–30.4), and non-TNF-targeted bDMARDs had 12 IOIb, incidence 31.7 (18–55.9). In the multivariate analysis, glucocorticosteroids (HR 2.17, p = 0.004) and lower lymphocyte count increased the risk for IOIb (HR 0.99, p = 0.005).

Conclusions:

The incidence of IOIb due to bDMARDs was 23 cases per 1000 patient-years. Close monitoring should be taken in the RA patients treated with bDMARDs and glucocorticosteroids, mainly in elderly patients and those with a low total lymphocyte count at the beginning of bDMARD treatment.

Elevation of ambient temperature is associated with an increased risk of herpes zoster: a time-series analysis

Although varicella zoster (VZ) and herpes zoster (HZ) are caused by the same varicella zoster virus (VZV), the former is caused by primary infection while the latter is caused by reactivation of latent VZV, and their relationships with ambient temperature are also different. It is relatively well-established that VZ incidence declines with ambient temperature, but the relationship between HZ and ambient temperature is inconclusive. Thus, we investigated the effects of ambient temperature on the incidence of HZ in time-series analysis by using data from the Korean National Emergency Department Information System between 2014 and 2016. We applied a generalized linear model to investigate the relationship between ambient temperature and emergency room (ER) visits due to HZ, after controlling for confounders in seven metropolitan cities and nine provinces in South Korea. Region-specific estimates were pooled to obtain the national average estimates. There were a total of 61,957 ER visits nationwide for HZ during the study period. HZ significantly increased by 2.03% to 2.94% in the moving average lag models throughout 0 to 11 days with maximum percent increase of 2.94% (95% CI: 2.20, 3.68) in the 6-day moving average lag model.

Herpes Zoster in Patients Receiving JAK Inhibitors For Ulcerative Colitis: Mechanism, Epidemiology, Management, and Prevention

Increased risk of herpes zoster (HZ) has been observed in patients with immune-mediated diseases, including rheumatoid arthritis (RA), psoriasis (PsO), and inflammatory bowel disease; this risk can be further increased by the use of immunosuppressive therapy. One advancing modality of therapy for these diseases is Janus kinase (JAK) inhibition. Tofacitinib is an oral JAK inhibitor for the treatment of RA and psoriatic arthritis, which is currently under investigation for the treatment of ulcerative colitis (UC) and was previously investigated for psoriasis. JAK inhibitors have been associated with HZ events in patients across a number of indications. The pathogenesis underlying this risk of HZ is currently unknown. An increased risk of HZ has been noted in patients receiving immunosuppressive therapies for UC, including tofacitinib. In clinical trials, there was a dose-dependent risk of HZ (higher dose linked with increased risk). However, the majority of HZ cases are nonserious and noncomplicated, mild to moderate in severity, and manageable without permanent discontinuation of treatment. This review will discuss HZ risk in patients receiving JAK inhibitors, focusing on tofacitinib with respect to the potential mechanisms and epidemiology of HZ. Current guidelines for the prevention of HZ will be highlighted, and proposed management reviewed.

Enhancement of cutaneous immunity during aging by blocking p38 mitogen-activated protein (MAP) kinase-induced inflammation

Background

Immunity decreases with age, which leads to reactivation of varicella zoster virus (VZV). In human subjects age-associated immune changes are usually measured in blood leukocytes; however, this might not reflect alterations in tissue-specific immunity.

Objectives

We used a VZV antigen challenge system in the skin to investigate changes in tissue-specific mechanisms involved in the decreased response to this virus during aging.

Methods

We assessed cutaneous immunity based on the extent of erythema and induration after intradermal VZV antigen injection. We also performed immune histology and transcriptomic analyses on skin biopsy specimens taken from the challenge site in young (<40 years) and old (>65 years) subjects.

Results

Old human subjects exhibited decreased erythema and induration, CD4⁺ and CD8⁺ T-cell infiltration, and attenuated global gene activation at the site of cutaneous VZV antigen challenge compared with young subjects. This was associated with increased sterile inflammation in the skin in the same subjects related to p38 mitogen-activated protein kinase–related proinflammatory cytokine production (P < .0007). We inhibited systemic inflammation in old subjects by means of pretreatment with an oral small-molecule p38 mitogen-activated protein kinase inhibitor (Losmapimod; GlaxoSmithKline, Brentford, United Kingdom), which reduced both serum C-reactive protein levels and peripheral blood monocyte secretion of IL-6 and TNF-α. In contrast, cutaneous responses to VZV antigen challenge were increased significantly in the same subjects (P < .0003).

Conclusion

Excessive inflammation in the skin early after antigen challenge retards antigen-specific immunity. However, this can be reversed by inhibition of inflammatory cytokine production that can be used to promote vaccine efficacy and the treatment of infections and malignancy during aging.

Varicella-Zoster Virus Activates CREB, and Inhibition of the pCREB-p300/CBP Interaction Inhibits Viral Replication In Vitro and Skin Pathogenesis In Vivo

Varicella-zoster virus (VZV) is an alphaherpesvirus that causes varicella upon primary infection and zoster upon reactivation from latency in sensory ganglion neurons. The replication of herpesviruses requires manipulation of cell signaling pathways. Notably, CREB, a factor involved in the regulation of several cellular processes, is activated upon infection of T cells with VZV. Here, we report that VZV infection also induced CREB phosphorylation in fibroblasts and that XX-650-23, a newly identified inhibitor of the phosphorylated-CREB (pCREB) interaction with p300/CBP, restricted cell-cell spread of VZV in vitro CREB phosphorylation did not require the viral open reading frame 47 (ORF47) and ORF66 kinases encoded by VZV. Evaluating the biological relevance of these observations during VZV infection of human skin xenografts in the SCID mouse model of VZV pathogenesis showed both that pCREB was upregulated in infected skin and that treatment with XX-650-23 reduced infectious-virus production and limited lesion formation compared to treatment with a vehicle control. Thus, processes of CREB activation and p300/CBP binding are important for VZV skin infection and may be targeted for antiviral drug development.

IMPORTANCE

Varicella-zoster virus (VZV) is a common pathogen that causes chicken pox and shingles. As with all herpesviruses, the infection is acquired for life, and the virus can periodically reactivate from latency. Although VZV infection is usually benign with few or no deleterious consequences, infection can be life threatening in immunocompromised patients. Otherwise healthy elderly individuals who develop zoster as a consequence of viral reactivation are at risk for postherpetic neuralgia (PHN), a painful and long-lasting complication. Current vaccines use a live attenuated virus that is usually safe but cannot be given to many immunodeficient patients and retains the capacity to establish latency and reactivate, causing zoster. Antiviral drugs are effective against severe VZV infections but have little impact on PHN. A better understanding of virus-host cell interactions is relevant for developing improved therapies to safely interfere with cellular processes that are crucial for VZV pathogenesis.

Modulation of host CD59 expression by varicella-zoster virus in human xenografts in vivo

Varicella-zoster virus (VZV) is the causative agent of both chickenpox (varicella) and shingles (zoster). VZV survives host defenses, even with an intact immune system, and disseminates in the host before causing disease. To date, several diverse immunomodulatory strategies used by VZV to undermine host immunity have been identified; however, few studies have addressed the complement evasion strategies used by this virus. Here, we show that expression of CD59, which is a key member of host regulators of complement activation (RCA), is significantly upregulated in response to VZV infection in human T cells and dorsal root ganglia (DRG) but not in human skin xenografts in SCID-hu mice in vivo. This is the first report demonstrating that VZV infection upregulates host CD59 expression in a tissue-specific manner in vivo, which may aid VZV in complement evasion and pathogenesis.

CD4 T cell responses in latent and chronic viral infections

The spectrum of tasks which is fulfilled by CD4 T cells in the setting of viral infections is large, ranging from support of CD8 T cells and humoral immunity to exertion of direct antiviral effector functions. While our knowledge about the differentiation pathways, plasticity, and memory of CD4 T cell responses upon acute infections or immunizations has significantly increased during the past years, much less is still known about CD4 T cell differentiation and their beneficial or pathological functions during persistent viral infections. In this review we summarize current knowledge about the differentiation, direct or indirect antiviral effector functions, and the regulation of virus-specific CD4 T cells in the setting of persistent latent or active chronic viral infections with a particular emphasis on herpes virus infections for the former and chronic lymphocytic choriomeningitis virus infection for the latter.

Attenuation of the adaptive immune response in rhesus macaques infected with simian varicella virus lacking open reading frame 61

Varicella zoster virus (VZV) is a neurotropic alphaherpesvirus that causes chickenpox during primary infection and establishes latency in sensory ganglia. Infection of rhesus macaques (RM) with the homologous simian varicella virus (SVV) recapitulates hallmarks of VZV infection. We have shown that an antisense transcript of SVV open reading frame 61 (ORF61), a viral transactivator, was detected most frequently in latently infected RM sensory ganglia. In this study, we compared disease progression, viral replication, immune response, and the establishment of latency following intrabronchial infection with a recombinant SVV lacking ORF61 (SVVΔORF61) to those following infection with wild-type (WT) SVV. Varicella severity and viral latency within sensory ganglia were comparable in RMs infected with SVVΔORF61 and WT SVV. In contrast, viral loads, B and T cell responses, and plasma inflammatory cytokine levels were decreased in RMs infected with SVVΔORF61. To investigate the mechanisms underlying the reduced adaptive immune response, we compared acute SVV gene expression, frequency and proliferation of dendritic cell (DC) subsets, and the expression of innate antiviral genes in bronchoalveolar lavage (BAL) samples. The abundance of SVV transcripts in all kinetic classes was significantly decreased in RMs infected with SVVΔORF61. In addition, we detected a higher frequency and proliferation of plasmacytoid dendritic cells in BAL fluid at 3 days postinfection in RMs infected with SVVΔORF61, which was accompanied by a slight increase in type I interferon gene expression. Taken together, our data suggest that ORF61 plays an important role in orchestrating viral gene expression in vivo and interferes with the host antiviral interferon response.

CD4 T cell immunity is critical for the control of simian varicella virus infection in a nonhuman primate model of VZV infection

Primary infection with varicella zoster virus (VZV) results in varicella (more commonly known as chickenpox) after which VZV establishes latency in sensory ganglia. VZV can reactivate to cause herpes zoster (shingles), a debilitating disease that affects one million individuals in the US alone annually. Current vaccines against varicella (Varivax) and herpes zoster (Zostavax) are not 100% efficacious. Specifically, studies have shown that 1 dose of varivax can lead to breakthrough varicella, albeit rarely, in children and a 2-dose regimen is now recommended. Similarly, although Zostavax results in a 50% reduction in HZ cases, a significant number of recipients remain at risk. To design more efficacious vaccines, we need a better understanding of the immune response to VZV. Clinical observations suggest that T cell immunity plays a more critical role in the protection against VZV primary infection and reactivation. However, no studies to date have directly tested this hypothesis due to the scarcity of animal models that recapitulate the immune response to VZV. We have recently shown that SVV infection of rhesus macaques models the hallmarks of primary VZV infection in children. In this study, we used this model to experimentally determine the role of CD4, CD8 and B cell responses in the resolution of primary SVV infection in unvaccinated animals. Data presented in this manuscript show that while CD20 depletion leads to a significant delay and decrease in the antibody response to SVV, loss of B cells does not alter the severity of varicella or the kinetics/magnitude of the T cell response. Loss of CD8 T cells resulted in slightly higher viral loads and prolonged viremia. In contrast, CD4 depletion led to higher viral loads, prolonged viremia and disseminated varicella. CD4 depleted animals also had delayed and reduced antibody and CD8 T cell responses. These results are similar to clinical observations that children with agammaglobulinemia have uncomplicated varicella whereas children with T cell deficiencies are at increased risk of progressive varicella with significant complications. Moreover, our studies indicate that CD4 T cell responses to SVV play a more critical role than antibody or CD8 T cell responses in the control of primary SVV infection and suggest that one potential mechanism for enhancing the efficacy of VZV vaccines is by eliciting robust CD4 T cell responses.

Varicella zoster virus (VZV) causes chickenpox and establishes a life-long latent infection in humans. VZV can reactivate years later to cause shingles, a debilitating and painful disease. Vaccines against both chickenpox and shingles are available but not 100% efficacious. Two doses of the chickenpox vaccine are required to provide adequate protection and the shingles vaccine reduces the incidence of this disease by 51%. To improve these vaccines, we must identify the components of the immune system that are important for the control of VZV replication. However, the contribution of T versus B cell responses is unknown. Infection of rhesus macaques with simian varicella virus is a robust model of VZV infection. Here, we used this unique animal model to show for the first time that the absence of B cells does not alter disease severity and that the loss of CD8 T cells only results in a mild increase in disease severity. In sharp contrast, the lack of CD4 T cells leads to disseminated varicella. These data highlight the importance of CD4 T cells and suggest that novel vaccines that focus on engendering a more robust CD4 T cell response against VZV might provide better protection from chickenpox and shingles.

Incidence of herpes zoster in patients with giant cell arteritis: a population-based cohort study

OBJECTIVES

To determine the incidence of herpes zoster (HZ) in GCA.

METHODS

Utilizing the resources of the Rochester Epidemiology Project, all incident cases of GCA diagnosed between 1 January 1950 and 31 December 2004 were identified. For each GCA patient, two subjects without GCA of the same gender and similar age and length of medical history were randomly selected from the population. Patients were followed until death, last contact or 31 December 2006.

RESULTS

The study population included 204 GCA patients and 407 non-GCA subjects. The GCA cohort had 163 (79%) women and 41 (21%) men, with a mean age of 76.0 (8.2) years. The non-GCA cohort had 325 (80%) women and 82 (20%) men, with a mean age of 75.6 (8.4) years. During follow-up, 21 GCA patients and 38 non-GCA subjects developed HZ. There was no difference in the development of HZ in GCA patients compared with non-GCA patients [hazard ratio (HR): 1.22; 95% CI 0.71, 2.08; adjusted for age, sex and calendar year]. No GCA patient and one non-GCA subject developed HZ within 6 months of index date. The frequency of post-herpetic neuralgia was similar between both groups (P = 0.64).

CONCLUSIONS

Patients with GCA do not appear to be at increased risk of HZ compared with the general population, even during the first 6 months of therapy when glucocorticoid doses are usually highest.

Identification of an important immunological difference between virulent varicella-zoster virus and its avirulent vaccine: viral disruption of dendritic cell instruction

Virulent varicella-zoster virus (VZV) can spread in immunocompetent humans, resulting in symptoms mostly of the skin. In contrast, vaccine Oka (V-Oka), the attenuated VZV vaccine strain, only rarely causes clinical reactions. The mechanisms underlying these pathogenetic differences are unclear. In this study, we comparatively analyzed the ability of virulent VZV and V-Oka to modulate instruction of dendritic cells (DCs) by innate signals. DCs isolated from normal human skin were susceptible to infection with VZV and V-Oka. Moreover, inflammatory DCs, which play a crucial role in the stimulation of Th1 immune responses, accumulated in herpes zoster lesions. Infection of inflammatory DCs generated in vitro with virulent VZV or V-Oka resulted in upregulation of CD1c. Upon coculture with CD1c-restricted innate cells, DCs developed a mature phenotype whether infected with virulent VZV or V-Oka. Intriguingly, a striking difference was detected on the functional level. The release of IFN-gamma and IL-12, the signature cytokines of Th1 responses, was enhanced by V-Oka but blocked by virulent VZV. V-Oka and virulent VZV efficiently synergized with CD40L, eliminating the possibility that CD40 signaling was a target of VZV-associated immune evasion. Instead, virulent VZV selectively interfered with signaling through TLR2, which is known to sense VZV. Thus, virulent VZV subverts Th1-promoting instruction of human DCs by blocking TLR2-mediated innate signals that prime IL-12 production by DCs. Taken together, our results demonstrate a novel immune-evasion mechanism of virulent VZV that has been lost during the attenuation process leading to the VZV vaccine strain.

Varicella zoster virus immune evasion strategies

The capacity of varicella zoster virus (VZV) to cause varicella (chickenpox) relies upon multiple steps, beginning with inoculation of the host at mucosal sites with infectious virus in respiratory droplets. Despite the presence of a powerful immune defense system, this virus is able to disseminate from the site of initial infection to multiple sites, resulting in the emergence of distinctive cutaneous vesiculopustular lesions. Most recently, it has been proposed that the steps leading to cutaneous infection include VZV infecting human tonsillar CD4(+) T cells that express skin homing markers that allow them to transport VZV directly from the lymph node to the skin during the primary viremia. It has also been proposed that dendritic cells (DC) of the respiratory mucosa may be among the first cells to encounter VZV and these cells may transport virus to the draining lymph node. These various virus-host cell interactions would all need to occur in the face of an intact host immune response for the virus to successfully cause disease. Significantly, following primary exposure to VZV, there is a prolonged incubation period before emergence of skin lesions, during which time the adaptive immune response is delayed. For these reasons, it has been proposed that VZV must encode functions which benefit the virus by evading the immune response. This chapter will review the diverse array of immunomodulatory mechanisms identified to date that VZV has evolved to at least transiently limit immune recognition.

Influence of systemic immune and cytokine responses during the acute phase of zoster on the development of postherpetic neuralgia

Postherpetic neuralgia (PHN) is a severe sequela of herpes zoster (HZ). Until now, only age and pain severity were considered predisposing factors for the development of PHN. We evaluated 49 patients with acute phase HZ, 10 of whom developed PHN (Group A) and 39 of whom did not develop PHN (Group B). Twenty-five healthy volunteers similar in age and gender distribution to the study group were recruited as controls (Group C). Numbers of serum CD3(+) (pan-T lymphocytes), CD4(+) (helper/inducer), and CD8(+) (suppressor/cytotoxic) lymphocytes were decreased significantly in Groups A and B relative to the control group, but there were no statistical differences between Groups A and B. Interleukin (IL)-1beta, IL-6, tumor necrosis factor (TNF)-alpha, IL-8, and IL-10 were significantly elevated in Groups A and B relative to Group C. IL-6 was significantly higher in Group A than in Group B, and was significantly positively correlated with pain severity scored on a visual analog scale. Therefore, we suggest that the inflammatory response, especially that of IL-6, in the acute phase of HZ may be associated with hyperalgesia and the development of PHN.

Replicating viral vectors as HIV vaccines Summary Report from IAVI Sponsored Satellite Symposium, International AIDS Society Conference, July 22, 2007

At the International AIDS Society Conference on Pathogenesis, Treatment and Prevention held in Sydney, Australia, in July 2007, the International AIDS Vaccine Initiative (IAVI) convened a satellite symposium entitled 'Accelerating the Development of Replicating Viral Vectors for AIDS Vaccines.' Its purpose was to highlight the rationale for accelerating the development of replicating viral vectors for use as vaccines against HIV-1, and to bring together vaccine scientists, regulatory officials, and public health specialists from industrialized and developing nations to discuss the major issues facing the development and testing of replicating viral vector-based vaccines.

Varicella zoster virus glycoprotein E-specific CD4+ T cells show evidence of recent activation and effector differentiation, consistent with frequent exposure to replicative cycle antigens in healthy immune donors

Varicella zoster viru (VZV)-specific T cell responses are believed to be vital in recovery from primary VZV infection and also in the prevention of viral reactivation. While glycoprotein E (gE) is the most abundant and one of the most immunogenic proteins of the virus, there are no data addressing potential T cell epitopes within gE, nor the phenotype of specific T cells. Using interferon gamma enzyme-linked immunospot assays and intracellular cytokine assays, we identified gE-specific immune responses in 20 adult healthy immune donors which were found to be dominated by the CD4+ subset of T cells. We characterized three immune dominant epitopes within gE restricted through DRB1*1501, DRB1*07 and DRB4*01, and used DRB1*1501 class II tetrameric complexes to determine the ex vivo frequency and phenotype of specific T cells. In healthy immune donors, the cells were largely positive for CCR7, CD28 and CD27, but expressed variable CD62L and low levels of cutaneous lymphocyte associated antigen with evidence of recent activation. In summary, we show that circulating gE-specific CD4+ T cells are detected at a relatively high frequency in healthy immune donors and show evidence of recent activation and mixed central and effector memory phenotype. These data would be compatible with frequent exposure to replicative cycle antigens in healthy donors and are consistent with a role for gE-specific CD4+ T cells in the control of viral replication.

Simian varicella virus reactivation in cynomolgus monkeys

SVV infection of primates closely resembles VZV infection of humans. Like VZV, SVV becomes latent in ganglionic neurons. We used this model to study the effect of immunosuppression on varicella reactivation. Cynomolgus monkeys latently infected with SVV were irradiated and treated with tacrolimus and prednisone. Of four latently infected monkeys that were immunosuppressed and subjected to the stress of transportation and isolation, one developed zoster, and three others developed features of subclinical reactivation. Another non-immunosuppressed latently infected monkey that was subjected to the same stress of travel and isolation showed features of subclinical reactivation. Virus reactivation was confirmed not only by the occurrence of zoster in one monkey, but also by the presence of late SVV RNA in ganglia, and the detection of SVV DNA in non-ganglionic tissue, and SVV antigens in skin, ganglia and lung.

Further characterization of a rat model of varicella zoster virus-associated pain: Relationship between mechanical hypersensitivity and anxiety-related behavior, and the influence of analgesic drugs

Persistent herpes zoster-associated pain is a significant clinical problem and an area of largely unmet therapeutic need. Progress in elucidating the underlying pathophysiology of zoster-associated pain and related co-morbidity behavior, in addition to appropriately targeted drug development has been hindered by the lack of an appropriate animal model. This study further characterizes a recently developed rat model of zoster-associated hypersensitivity and investigates (a) response to different viral strains; (b) relationship between viral inoculum concentration ('dose') and mechanical hypersensitivity ('response'); (c) attenuation of virus-associated mechanical hypersensitivity by clinically useful analgesic drugs; and (d) measurement of pain co-morbidity (anxiety-like behavior) and pharmacological intervention in the open field paradigm (in parallel with models of traumatic peripheral nerve injury). Varicella zoster virus was propagated on fibroblast cells before s.c. injection into the glabrous footpad of the left hind limb of adult male Wistar rats. Control animals received injection of uninfected fibroblast cells. Hind-limb reflex withdrawal thresholds to mechanical, noxious thermal and cooling stimuli were recorded at specified intervals post-infection. Infection with all viral strains was associated with a dose-dependent mechanical hypersensitivity but not a thermal or cool hypersensitivity. Systemic treatment with i.p. morphine (2.5 mg/kg), amitriptyline (10 mg/kg), gabapentin (30 mg/kg), (S)-(+)-ibuprofen (20 mg/kg) and the cannabinoid WIN55,212-2 (2 mg/kg) but not the antiviral, acyclovir (50 mg/kg), was associated with a reversal of mechanical paw withdrawal thresholds. In the open field paradigm, virus-infected and nerve-injured animals demonstrated an anxiety-like pattern of ambulation (reduced entry into the central area of the open arena) which was positively correlated with mechanical hypersensitivity. This may reflect pain-related co-morbidity. Further, anxiety-like behavior was attenuated by acute i.p. administration of gabapentin (30 mg/kg) in nerve-injured, but not virus-infected animals. This model will prove useful in elucidating the pathophysiology of zoster-associated pain and provide a tool for pre-clinical screening of analgesic drugs.

Marek's disease virus up-regulates major histocompatibility complex class II cell surface expression in infected cells

Many herpesviruses modulate major histocompatibility complex (MHC) expression on the cell surface as an immune evasion mechanism. We report here that Marek's disease virus (MDV), a lymphotrophic avian alphaherpesvirus, up-regulates MHC class II cell surface expression in infected cells, contrary to all other herpesviruses examined to date. This MDV-induced class II up-regulation was detected both in vitro and in vivo. This effect was not solely an indirect effect of interferon, which is a highly potent natural inducer of MHC class II expression, since MHC class II up-regulation in cultured primary fibroblast cells was confined to the infected cells only. MHC class II up-regulation was also observed in infected cells of the bursa of Fabricius during the lytic phase of MDV infection in birds and upon reactivation of MDV from latency in an MDV-transformed cell line. As MDV is a strictly cell-associated virus and requires activated T cells for its life cycle, this up-regulation of MHC class II in infected cells may contribute to virus spread within the infected host by increasing the chance of contact between productively infected cells and susceptible activated T cells.

Molecular studies of Varicella zoster virus

VZV is a highly cell-associated member of the Herpesviridae family and one of the eight herpesviruses to infect humans. The virus is ubiquitous in most populations worldwide, primary infection with which causes varicella, more commonly known as chickenpox. Characteristic of members of the alphaherpesvirus sub-family, VZV is neurotropic and establishes latency in sensory neurones. Reactivation from latency, usually during periods of impaired cellular immunity, causes herpes zoster (shingles). Despite being one of the most genetically stable human herpesviruses, nucleotide alterations in the virus genome have been used to classify VZV strains from different geographical regions into distinct clades. Such studies have also provided evidence that, despite pre-existing immunity to VZV, subclinical reinfection and reactivation of reinfecting strains to cause zoster is also occurring. During both primary infection and reactivation, VZV infects several PBMC and skin cell lineages. Difficulties in studying the pathogenesis of VZV because of its high cell association and narrow host range have been overcome through the development of the VZV severe combined immunodeficient mouse model carrying human tissue implants. This model has provided a valuable tool for studying the importance of individual viral proteins during both the complex intracellular replication and assembly of new virions and for understanding the underlying mechanism of attenuation of the live varicella vaccine. In addition, a rat model has been developed and successfully used to uncover which viral proteins are important for both the establishment and maintenance of latent VZV infection.

Herpes zoster in immunocompromised patients: incidence, timing, and risk factors

PURPOSE

To evaluate the risk factors for herpes zoster as well as the incidence and timing of this complication in patients who were treated with immunosuppression because of active Wegener's granulomatosis.

SUBJECTS AND METHODS

We studied the 180 Wegener's granulomatosis patients in the Wegener's Granulomatosis Etanercept Trial (WGET). Herpes zoster events during WGET were documented prospectively. Follow-up questionnaires were employed to describe the location, treatment, and complication(s) of herpes zoster and its therapy. Univariate and multivariate analyses were performed to evaluate risk factors, including history of herpes zoster, for the occurrence of herpes zoster during the trial. All analyses were based on the time to first occurrence of herpes zoster.

RESULTS

Eighteen patients (10% of the WGET cohort) suffered a total of 19 herpes zoster episodes over a mean follow-up period of 27 months. The annual incidence of herpes zoster in the WGET cohort was 45 cases/1000 patient-years (95% confidence interval [CI]: 27, 70). The median time from enrollment to the occurrence of herpes zoster in the subgroup of patients with that complication was 16.5 months (+/- 9.4). Fifteen of the 19 herpes zoster events (79%) occurred between months 6 and 36, many months after the period of most intensive immunosuppression. In univariate analyses, history of serum creatinine > or =1.5 mg/dL before enrollment was associated with a relative risk (RR) of 3.0 (95% CI: 1.1, 7.8) for herpes zoster during WGET (P=.03). In multivariate analyses, serum creatinine > or =1.5 mg/dL was associated with an RR of 6.3 (95% CI: 2.0, 19.8; P=.002), and female sex with an RR of 4.6 (95% CI: 1.6, 13.2; P=.004).

CONCLUSION

Renal dysfunction and female sex were consistently strong risk factors for herpes zoster events in this population. Contrary to expectation, most herpes zoster events did not occur during periods of most intensive immunosuppression. These data may inform studies of interventions designed to prevent herpes zoster in patients on treatment for immune-mediated diseases.

In vitro delivery of novel, highly potent anti-varicella zoster virus nucleoside analogues to their target site in the skin

PURPOSE

To determine the in-vitro dermal delivery of a new class of lipophilic, highly potent and uniquely selective anti-VZV nucleoside analogues in comparison with aciclovir.

METHODS

Three test compounds (Cf1698, Cf1743, Cf1712) and aciclovir were formulated into propylene glycol/aqueous cream BP formulations and finite doses applied to full-thickness pig ear skin for 48 hours in vertical Franz-type diffusion cells. Receptor phase samples were taken at specific intervals to determine permeation, and depth profiles were constructed following tape stripping and membrane separation.

RESULTS

All three test compounds reached the target basal epidermis in concentrations suggesting they would be highly efficacious in reducing viral load. Furthermore, the data showed that each of the test compounds would perform in a far superior manner to aciclovir, the current treatment of choice.

CONCLUSIONS

The dermatomal site of viral replication during secondary infection--the basal epidermis--was successfully targeted. Topical delivery of these compounds is highly promising as a new first line treatment of VZV infections. By attacking the virus at the first sign of reactivation, it is proposed that the extent of damage caused by the virus would be significantly lowered, thereby limiting the extent and severity of post-herpetic neuralgia.

Targeted dermal delivery of highly potent anti-varicella zoster virus nucleoside analogues from saturated solutions and ethanolic oil-in-water creams

Varicella zoster virus (VZV) is responsible for causing chickenpox and shingles infections, the latter of which can lead to long-term post-herpetic neuralgia (PHN), the most common complication of VZV infections. A class of anti-VZV nucleoside analogues has been synthesised that shows up to 30,000 times the potency of aciclovir in vitro. The relatively high lipophilicities exhibited by the compounds led them to be selected for dermal delivery. The aim was to assess the relative penetration and permeation of the compounds into and through the skin, ideally targeting the region of skin in which the reactivated virus replicates. By targeting the skin it should be possible to reduce the viral load that causes damage to the nerves, thereby limiting zoster-associated pain, in particular PHN. Three compounds, as saturated solutions or as ethanol-based creams, were applied to full-thickness pig ear skin in Franz-type diffusion cells. An ethanolic and water receptor phases were compared. Samples of the receptor phase were taken at specific intervals, followed by tape stripping and separation of the remaining membrane at the end of the experiment. Analysis of the samples showed that all three compounds penetrated into the ethanolic receptor phase to a considerable degree, while only the least lipophilic compound entered the water receptor phase. The effects of the organic solvent in the receptor phase were visible in both the penetration and permeation of the compounds. All three compounds were distributed throughout the membrane in a manner that indicates that the site of viral replication in the skin is reached.

The human histocompatibility leukocyte antigen (HLA) haplotype is associated with the onset of postherpetic neuralgia after herpes zoster

In some herpes zoster patients, pain persists for more than 3 months or more after healing of vesicular eruptions; this condition is termed postherpetic neuralgia (PHN). We have recently reported the association of the human histocompatibility leukocyte antigens (HLA) haplotype, HLA-A*3303-B*4403-DRB1*1302 with PHN patients; however, it has not been determined whether the haplotype is also associated with herpes zoster that did not develop subsequent PHN. To distinguish whether the haplotype is associated with herpes zoster or the development of PHN, we examined if herpes zoster patients without subsequently PHN are also associated with the HLA haplotype or not. Herpes zoster patients were followed up for more than 6 months, and HLA alleles and haplotypes were compared among the PHN patients (n = 52) the herpes zoster patients who did not develop PHN (n = 42) and healthy controls (n = 125). The frequencies of the risk haplotype in the PHN patients, in the healthy controls and in the herpes zoster patients without subsequent PHN were 16.3, 5.2 and 4.8%, respectively. While the frequency of the risk haplotype was significantly higher in the PHN patients than in the healthy controls (P = 0.0006) no difference was observed between the herpes zoster patients without subsequent PHN and the healthy controls. No significant association was found between the duration of symptoms or the site of herpes zoster and the HLA alleles and the haplotype. These results suggest that the HLA-A*3303-B*4403-DRB1*1302 haplotype plays an important role in the development of PHN after herpes zoster, but not in the onset of herpes zoster.

Distinct domains in the adenovirus E3 RIDalpha protein are required for degradation of Fas and the epidermal growth factor receptor

Adenovirus (Ad) types 2 and 5 encode at least five proteins within the E3 transcription unit that help the virus evade the immune system. Two such proteins, RIDalpha (formerly E3-10.4K) and RIDbeta (formerly E3-14.5K), form the RID (receptor internalization and degradation) complex (formerly E3-10.4K/14.5K). RID mediates clearance from the cell surface and lysosomal degradation of a number of important members in the tumor necrosis factor receptor (TNFR) superfamily and the receptor tyrosine kinase receptor family. Affected receptors include Fas, TRAIL (TNF-related apoptosis-inducing ligand) receptor 1 (TR1), TR2, and epidermal growth factor receptor (EGFR). Degradation of Fas and TRAIL receptors protects Ad-infected cells from apoptosis. To investigate the mechanism of action of RIDalpha, 14 mutant RIDalpha proteins, each containing a three- to five-amino-acid deletion, were constructed and then expressed from the E3 region of a replication-competent recombinant Ad in the same context as wild-type RIDalpha. Each mutant protein was characterized with regard to five physical properties associated with wild-type RIDalpha, namely, protein stability, proteolytic cleavage, insertion into the membrane, complex formation with RIDbeta, and transport to the cell surface. Additionally, the mutant proteins were tested for their ability to mediate internalization and degradation of EGFR and Fas and to protect cells from Fas-mediated apoptosis. The majority of mutant RIDalpha proteins (8 out of 14) were physically similar to wild-type RIDalpha. With regard to functional characteristics, the cytoplasmic domain of RIDalpha is largely unimportant for receptor internalization and degradation and the extracellular domain of RIDalpha is important for down-regulation of EGFR but not Fas.

Local immune responses and systemic cytokine responses in zoster: relationship to the development of postherpetic neuralgia

Varicella zoster virus (VZV) causes varicella (chickenpox) as the primary infection and zoster (shingles) on reactivation from latency, often many years later. One of the most common and most severe sequela of zoster is postherpetic neuralgia (PHN). Apart from age, factors which predispose towards PHN are unknown. In the present study, the concentration of a variety of Th1 and Th2 cytokines in the serum of 30 zoster patients at the time of the acute disease were correlated with the subsequent development of PHN in nine of these patients, but no association was found. In addition, although some cytokines such as IFN-gamma, IL-6 and IL-8 were slightly raised in the zoster group compared with a group of normal healthy subjects of a similar age distribution, these differences only verged on significance. Antibody titres to VZV were raised in the zoster group compared with the controls but these did not differ between the patients who developed PHN and those who did not. Biopsies of zoster lesions were collected from nine patients. There were significantly fewer infiltrating lymphocytes in the lesions of the three patients who subsequently developed PHN compared with the six who did not, although the expression of the neuropeptide, substance P, did not differ between the two groups. It is possible that the poor inflammatory response at the time of the acute zoster may result in less effective containment of the VZV and more damage in the dermatome, thus contributing to the persistence of the neuralgia.