Toll-like receptor sensing of human herpesvirus infection

Risk of Herpes Zoster Ophthalmicus After COVID-19 Vaccination in a Large US Health Care Claims Database

PURPOSE

Herpes zoster ophthalmicus (HZO) after COVID-19 vaccination has been reported in numerous case studies. However, no large-scale epidemiologic studies have been conducted to date. The purpose of this study was to determine whether COVID-19 vaccination is associated with an increased risk of HZO.

DESIGN

Retrospective before-and-after risk interval analysis.

METHODS

RESULTS: In total, 1,959,157 patients received a dose of a COVID-19 vaccine during the study period and met eligibility criteria. A total of 80 individuals without a prior history of HZO were included in the analysis because they developed HZO in the risk or control period. Patients had a mean age of 54.0 years (SD = 12.3 years). There were 45 cases of HZO in the risk interval after COVID-19 vaccination. There was not an increased risk of HZO after vaccination with BNT162b2 (IRR = 0.90, 95% CI: 0.49-1.69, P = .74), mRNA-1273 (IRR = 0.74, 95% CI: 0.36-1.54, P = .42), or Ad26.COV2.S (IRR = 0.50, 95% CI: 0.07-2.56, P = .42).

CONCLUSIONS

This study found no evidence of increased risk of HZO after COVID-19 vaccination, providing reassurance for patients and providers who may be concerned about the safety profile of the COVID-19 vaccines.

Herpes Zoster Reactivation After mRNA and Adenovirus-Vectored Coronavirus Disease 2019 Vaccination: Analysis of National Health Insurance Database

BACKGROUND

Our study aimed to determine the risk of herpes zoster reactivation and coronavirus disease 2019 (COVID-19) vaccination (mRNA vaccine [BNT162b2] and adenovirus-vectored vaccine [ChAdOx1 nCoV-19]).

METHODS

This retrospective study analyzed herpes zoster cases diagnosed between 26 February 2021 and 30 June 2021 and registered in the National Health Insurance Service database. A matched case-control study with a 1:3 matching ratio and a propensity score matching (PSM) study with a 1:1 ratio of vaccinated and unvaccinated individuals were performed.

RESULTS

In the matched case control analysis, BNT162b2 was associated with an increased risk of herpes zoster reactivation (first dose adjusted odds ratio [aOR], 1.11; 95% confidence interval [CI], 1.06-1.15; second dose aOR, 1.17; 95% CI, 1.12-1.23). PSM analysis revealed a statistically significant increase in risk within 18 days following any vaccination (adjusted hazard ratio [aHR], 1.09; 95% CI, 1.02-1.16). BNT162b2 was associated with an increased risk at 18 days postvaccination (aHR, 1.65; 95% CI, 1.35-2.02) and second dose (aHR, 1.10; 95% CI, 1.02-1.19). However, the risk did not increase in both analyses of ChAdOx1 vaccination.

CONCLUSIONS

mRNA COVID-19 vaccination possibly increases the risk of herpes zoster reactivation, and thus close follow-up for herpes zoster reactivation is required.

Multiregional Population-Based Cohort Study for Evaluation of the Association Between Herpes Zoster and mRNA Vaccinations for Severe Acute Respiratory Syndrome Coronavirus-2: The VENUS Study

Background

This study was performed to assess the increased risk of herpes zoster (HZ) associated with mRNA vaccines for coronavirus disease 2019.

Methods

This population-based cohort study was conducted in 4 municipalities in Japan. Individuals covered under public health insurance systems without a history of HZ were followed from October 1, 2020 to November 30, 2021. Incidence rates of HZ within 28 days of BNT162b2 or mRNA-1273 vaccination were compared. Adjusted incidence rate ratios (IRR) and 95% confidence intervals (CI) were estimated using a Poisson regression model, including vaccination status as a time-dependent covariate. Subgroup analyses by sex, age, and municipality were also conducted.

Results

A total of 339 548 individuals (median age, 74 years) were identified. During follow up, 296 242 individuals (87.2%) completed the primary series, among whom 289 213 and 7019 individuals received homologous BNT162b2 and mRNA-1273 vaccines, respectively. The adjusted IRRs of the first and second BNT162b2 vaccinations were 1.05 (95% CI, 0.84-1.32) and 1.09 (95% CI, 0.90-1.32), respectively. No cases of HZ were observed after mRNA-1273 vaccination. In subgroup analysis, the adjusted IRR of the second BNT162b2 vaccination was 2.94 (95% CI, 1.41-6.13) in individuals aged <50 years old.

Conclusions

No increased risk of HZ was found after BNT162b2 vaccination in the overall study population. However, an increased risk was observed in the younger subgroup.

Herpes Zoster Following COVID-19 Vaccine Booster

BACKGROUND Herpes zoster is a condition in which there is reactivation of varicella zoster virus (VZV), which is usually seen in the elderly and those with immunocompromised states. Recently, however, there have been many reports of herpes zoster after administration of COVID-19 vaccines, although initial trials showed that these vaccines have good safety and immunogenicity profiles. At the time of writing, about 5 billion people worldwide had received their full course of COVID-19 vaccination. This case report describes an elderly man who developed herpes zoster after receiving a booster dose of the Pfizer-BioNTech (BNT162b2) vaccine, with no adverse effects after the first and second dose. CASE REPORT An 82-year-old man with underlying type 2 diabetes mellitus, hypertension, dyslipidemia, and cerebrovascular disease presented with left-sided chest and upper back pain. The pain was intermittent, burning in nature, and disturbed his sleep. A week prior to his presentation, he received a COVID-19 vaccine (BNT162b2) booster dose. Examination revealed multiple vesicles along his anterior and posterior T3 dermatome. He was diagnosed with herpes zoster and treated with a course of oral acyclovir. Upon review 7 days later, he had recovered well, with resolution of his vesicles and pain. CONCLUSIONS COVID-19 vaccination remains an important measure to prevent transmission of infection and to reduce the mortality and morbidity caused by it. However, healthcare practitioners should be aware of the possible association between COVID-19 vaccination and herpes zoster. Appropriate explanation and safety advice on the possible adverse events following COVID-19 vaccination, including herpes zoster infection, should be given to patients. This will facilitate early recognition and treatment of this condition.

Assessment of Herpes Zoster Risk Among Recipients of COVID-19 Vaccine

Importance

Herpes zoster infection after COVID-19 vaccination has been reported in numerous case studies. It is not known whether these cases represent increased reporting or a true increase in risk.

Objective

To assess whether COVID-19 vaccination is associated with an increased risk of herpes zoster infection.

Design, Setting, and Participants

This cohort study used a self-controlled risk interval (SCRI) design to compare the risk of herpes zoster in a risk interval of 30 days after COVID-19 vaccination or up to the date of the second vaccine dose with a control interval remote from COVID-19 vaccination (defined as 60-90 days after the last recorded vaccination date for each individual, allowing for a 30-day washout period between control and risk intervals). A supplemental cohort analysis was used to compare the risk of herpes zoster after COVID-19 vaccination with the risk of herpes zoster after influenza vaccination among 2 historical cohorts who received an influenza vaccine in the prepandemic period (January 1, 2018, to December 31, 2019) or the early pandemic period (March 1, 2020, to November 30, 2020). Data were obtained from Optum Labs Data Warehouse, a US national deidentified claims-based database. A total of 2 039 854 individuals who received any dose of a COVID-19 vaccine with emergency use authorization (BNT162b2 [Pfizer-BioNTech], mRNA-1273 [Moderna], or Ad26.COV2.S [Johnson & Johnson]) from December 11, 2020, through June 30, 2021, were eligible for inclusion. Individuals included in the SCRI analysis were a subset of the COVID-19-vaccinated cohort who had herpes zoster during either a risk or control interval.

Exposures

Any dose of a COVID-19 vaccine.

Main Outcomes and Measures

Incident herpes zoster, defined by International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes and a prescription of a new antiviral medication or a dose increase in antiviral medication within 5 days of diagnosis.

Results

Among 2 039 854 individuals who received any dose of a COVID-19 vaccine during the study period, the mean (SD) age was 43.2 (16.3) years; 1 031 149 individuals (50.6%) were female, and 1 344 318 (65.9%) were White. Of those, 1451 patients (mean [SD] age, 51.6 [12.6] years; 845 [58.2%] female) with a herpes zoster diagnosis were included in the primary SCRI analysis. In the SCRI analysis, COVID-19 vaccination was not associated with an increased risk of herpes zoster after adjustment (incidence rate ratio, 0.91; 95% CI, 0.82-1.01; P = .08). In the supplementary cohort analysis, COVID-19 vaccination was not associated with a higher risk of herpes zoster compared with influenza vaccination in the prepandemic period (first dose of COVID-19 vaccine: hazard ratio [HR], 0.78 [95% CI, 0.70-0.86; P < .001]; second dose of COVID-19 vaccine: HR, 0.79 [95% CI, 0.71-0.88; P < .001]) or the early pandemic period (first dose of COVID-19 vaccine: HR, 0.89 [95% CI, 0.80-1.00; P = .05]; second dose: HR, 0.91 [95% CI, 0.81-1.02; P = .09]).

Conclusions and Relevance

In this study, there was no association found between COVID-19 vaccination and an increased risk of herpes zoster infection, which may help to address concerns about the safety profile of the COVID-19 vaccines among patients and clinicians.

Nanocarriers for effective delivery: modulation of innate immunity for the management of infections and the associated complications

Innate immunity is the first line of defense against invading pathogens. Innate immune cells can recognize invading pathogens through recognizing pathogen-associated molecular patterns (PAMPs) via pattern recognition receptors (PRRs). The recognition of PAMPs by PRRs triggers immune defense mechanisms and the secretion of pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6. However, sustained and overwhelming activation of immune system may disrupt immune homeostasis and contribute to inflammatory disorders. Immunomodulators targeting PRRs may be beneficial to treat infectious diseases and their associated complications. However, therapeutic performances of immunomodulators can be negatively affected by (1) high immune-mediated toxicity, (2) poor solubility and (3) bioactivity loss after long circulation. Recently, nanocarriers have emerged as a very promising tool to overcome these obstacles owning to their unique properties such as sustained circulation, desired bio-distribution, and preferred pharmacokinetic and pharmacodynamic profiles. In this review, we aim to provide an up-to-date overview on the strategies and applications of nanocarrier-assisted innate immune modulation for the management of infections and their associated complications. We first summarize examples of important innate immune modulators. The types of nanomaterials available for drug delivery, as well as their applications for the delivery of immunomodulatory drugs and vaccine adjuvants are also discussed.

Toll-like receptor-agonist-based therapies for respiratory viral diseases: thinking outside the cell

Respiratory virus infections initiate in the upper respiratory tract (URT). Innate immunity is critical for initial control of infection at this site, particularly in the absence of mucosal virus-neutralising antibodies. If the innate immune response is inadequate, infection can spread to the lower respiratory tract (LRT) causing community-acquired pneumonia (as exemplified by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)/coronavirus disease 2019). Vaccines for respiratory viruses (influenza and SARS-CoV-2) leverage systemic adaptive immunity to protect from severe lung disease. However, the URT remains vulnerable to infection, enabling viral transmission and posing an ongoing risk of severe disease in populations that lack effective adaptive immunity.

Innate immunity is triggered by host cell recognition of viral pathogen-associated molecular patterns via molecular sensors such as Toll-like receptors (TLRs). Here we review the role of TLRs in respiratory viral infections and the potential of TLR-targeted treatments to enhance airway antiviral immunity to limit progression to severe LRT disease and reduce person-to-person viral transmission. By considering cellular localisation and antiviral mechanisms of action and treatment route/timing, we propose that cell surface TLR agonist therapies are a viable strategy for preventing respiratory viral diseases by providing immediate, durable pan-viral protection within the URT.

Respiratory virus infections are a significant disease burden and new treatment options are required. Treatments that stimulate innate immunity in the upper respiratory tract by targeting Toll-like receptors may provide rapid, pan-viral protection.https://bit.ly/3BNH2Em

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

ETHNOPHARMACOLOGICAL RELEVANCE

Elaeocarpus sylvestris var. ellipticus (ES), a plant that grows in Taiwan, Japan, and Jeju Island in Korea. ES root bark, known as "sanduyoung," has long been used in traditional oriental medicine. ES is also traditionally used to treat anxiety, asthma, arthritis, stress, depression, palpitation, nerve pain, epilepsy, migraine, hypertension, liver diseases, diabetes, and malaria. However, lack of efficacy and mechanism studies on ES.

AIM OF THE STUDY

In the present study, we aim to investigate the VZV-antiviral efficacy, pain suppression, and the anti-inflammatory and antipyretic effects of ES.

METHODS

and methods: Inhibition of VZV was evaluated by hollow fiber assays. Analgesic and antipyretic experiments were conducted using ICR mice and SD Rats, and anti-inflammatory experiments were conducted using Raw264.7 cells.

RESULTS

To evaluate the efficacy of ESE against VZV, we conducted antiviral tests. ESE inhibited cell death by disrupting virus and gene expression related to invasion and replication. In addition, ESE suppressed the pain response as measured by writhing and formalin tests and suppressed LPS-induced inflammatory fever. Further, ESE inhibited the phosphorylation of IκB and NF-κB in LPS-induced Raw264.7 cells and expression of COX-2, iNOS, IL-1β, IL-6, and TNF-α.

CONCLUSION

E. sylvestris shows potential as a source of medicine. ESE had a direct effect on VZV and an inhibitory effect on the pain and inflammation caused by VZV infection.

Association study between herpes zoster reporting and mRNA COVID-19 vaccines (BNT162b2 and mRNA-1273)

Several cases of herpes zoster (HZ) following mRNA COVID‐19 vaccination (BNT162b2 and mRNA‐1273) have been reported, and the first epidemiological evidence suggests an increased risk. We used the worldwide pharmacovigilance database VigiBase to describe HZ cases following mRNA COVID‐19 vaccination. We performed disproportionality analyses (case/non‐case statistical approach) to assess the relative risk of HZ reporting in mRNA COVID‐19 vaccine recipients compared to influenza vaccine recipients and according to patient age. To 30 June 2021, of 716 928 reports with mRNA COVID‐19 vaccines, we found 7728 HZ cases. When compared to influenza vaccines, mRNA COVID‐19 vaccines were associated with a significantly higher reporting of HZ (reporting odds ratio 1.9, 95% CI 1.8–2.1). Furthermore, we found a reduced risk of reporting HZ among under 40‐year‐old persons compared to older persons (reporting odds ratio 0.39, 95% CI 0.36–0.41). Mild and infrequent HZ reactions may occur shortly after mRNA COVID‐19 vaccination, at higher frequency than reported with influenza vaccination, especially in patients over 40 years old. Further analyses are needed to confirm this risk.

Herpes zoster related hospitalization after inactivated (CoronaVac) and mRNA (BNT162b2) SARS-CoV-2 vaccination: A self-controlled case series and nested case-control study

Background

Stimulation of immunity by vaccination may elicit adverse events. There is currently inconclusive evidence on the relationship between herpes zoster related hospitalization and COVID-19 vaccination. This study aimed to evaluate the effect of inactivated virus (CoronaVac, Sinovac) and mRNA (BNT162b2, BioNTech/Fosun Pharma) COVID-19 vaccine on the risk of herpes zoster related hospitalization.

Methods

Self-controlled case series (SCCS) analysis was conducted using the data from the electronic health records in Hospital Authority and COVID-19 vaccination records in the Department of Health in Hong Kong. We conducted the SCCS analysis including patients with a first primary diagnosis of herpes zoster in the hospital inpatient setting between February 23 and July 31, 2021. A confirmatory analysis by nested case-control method was also conducted. Each herpes zoster case was randomly matched with ten controls according to sex, age, Charlson comorbidity index, and date of hospital admission. Conditional Poisson regression and logistic regression models were used to assess the potential excess rates of herpes zoster after vaccination.

Findings

From February 23 to July 31, 2021, a total of 16 and 27 patients were identified with a first primary hospital diagnosis of herpes zoster within 28 days after CoronaVac and BNT162b2 vaccinations. The incidence of herpes zoster was 7.9 (95% Confidence interval [CI]: 5.2-11.5) for CoronaVac and 7.1 (95% CI: 4.1-11.5) for BNT162b2 per 1,000,000 doses administered. In SCCS analysis, CoronaVac vaccination was associated with significantly higher risk of herpes zoster within 14 days after first dose (adjusted incidence rate ratio [aIRR]=2.67, 95% CI: 1.08-6.59) but not in other periods afterwards compared to the baseline period. Regarding BNT162b2 vaccination, a significantly increased risk of herpes zoster was observed after first dose up to 14 days after second dose (0-13 days after first dose: aIRR=5.23, 95% CI: 1.61-17.03; 14-27 days after first dose: aIRR=5.82, 95% CI: 1.62-20.91; 0-13 days after second dose: aIRR=5.14, 95% CI: 1.29-20.47). Using these relative rates, we estimated that there has been an excess of approximately 5 and 7 cases of hospitalization as a result of herpes zoster after every 1,000,000 doses of CoronaVac and BNT162b2 vaccination, respectively. The findings in the nested case control analysis showed similar results.

Interpretation

We identified an increased risk of herpes zoster related hospitalization after CoronaVac and BNT162b2 vaccinations. However, the absolute risks of such adverse event after CoronaVac and BNT162b2 vaccinations were very low. In locations where COVID-19 is prevalent, the protective effects on COVID-19 from vaccinations will greatly outweigh the potential side effects of vaccination.

Funding

The project was funded by Research Grant from the Food and Health Bureau, The Government of the Hong Kong Special Administrative Region (Ref. No.COVID19F01). FTTL (Francisco Tsz Tsun Lai) and ICKW (Ian Chi Kei Wong)'s posts were partly funded by D²4H; hence this work was partly supported by AIR@InnoHK administered by Innovation and Technology Commission.

Herpes Zoster Following COVID-19 Vaccination in Long-Term Breast Cancer Survivors

Mortality from coronavirus disease 2019 (COVID-19) is higher among patients with cancer. Vaccination represents a cornerstone in overcoming the disease, and vaccine safety needs to be closely assessed. This article discusses two cases of herpes zoster (HZ) following the administration of the BNT162b2 mRNA vaccine in patients who are long-term survivors of breast disease. HZ developed 24 days and two days after the second dose of the vaccine in women aged 81 and 61, respectively. These two patients were breast cancer operated respectively nine and 16 years before; interestingly HZ developed in the same site of previous surgical resection. The patients did not show lymphocytopenia or other signs of immunosuppression and were treated with acyclovir, resulting in the complete resolution of HZ. To our knowledge, these two patients are the first described cases of HZ reactivation following COVID-19 vaccination in cancer survivors.

Herpes Simplex Virus Keratitis Reactivation after SARS-CoV-2 BNT162b2 mRNA Vaccination: A Report of Two Cases

PURPOSE

To report two cases of herpes simplex virus keratitis reactivation following Pfizer-BioNTech COVID-19 (BNT162b2) mRNA vaccination.

METHODS

Two patients (one male, age 42 years, and one female, age 29 years) who are known to have herpetic keratitis presented to our emergency room in a time frame between 4 days and 4 weeks of receiving the vaccine. One patient presented with necrotizing stromal keratitis; the other presented with endotheliitis and epithelial keratitis. PCR for herpes simplex virus (HSV) was obtained from the two patients, and all cases received systemic acyclovir.

RESULTS

PCR for HSV came positive in both cases. Patients responded well to the provided treatment.

CONCLUSION

Ocular herpetic infection may be activated by COVID-19 (BNT162b2) mRNA vaccine. Treating physician should be alert to such associations, and patients should be followed closely. No direct causality has been proven, but further reporting and investigating similar conditions is recommended.

COVID-19 Vaccinations: A Comprehensive Review of Their Safety and Efficacy in Special Populations

COVID-19 has been spreading worldwide since late 2019. There is no definitive cure to date. Global vaccination programs are urgently required to confer herd immunity, reducing the incidence of COVID-19 infections and associated morbidity and mortality. However, a significant proportion of special populations are hesitant to receive vaccination due to their special conditions, namely, age (pediatrics and geriatrics), immunocompromised state, autoimmune diseases, chronic cardiovascular and pulmonary conditions, active or treated cancers, and pregnancy. This review aims to evaluate the existing evidence of COVID-19 vaccinations on these special populations and to provide clues to guide vaccination decision making to balance the benefits and risks of vaccinations.

Varicella Zoster Virus Reactivation Following COVID-19 Vaccination: A Systematic Review of Case Reports

The newly developed COVID-19 vaccines have established a safe profile, yet some individuals experience a wide range of adverse events. Recently, reactivation of varicella zoster virus (VZV) has been observed after administration of different COVID-19 vaccines, although causality remains a matter of debate. The aim of this systematic review was to examine the available literature and provide an overview of reported cases of VZV reactivation following COVID-19 vaccination. We identified 12 eligible articles which included 91 patients with herpes zoster (HZ) following COVID-19 vaccination. Hypertension was the main comorbidity present in 18% of patients (16/91). Additionally, 13% of patients (12/91) had an autoimmune condition with rheumatoid arthritis being the most common (4/12). Moreover, 10% of patients (9/91) were receiving immunosuppressants. The dermatomal distribution of skin lesions varied among patients, with the mammary region being most affected. On average, symptoms developed 5.8 days post-vaccination irrespective of dose and treatment with oral valacyclovir as a monotherapy was employed in most patients (23/91). HZ is possibly a condition clinicians may expect to encounter in patients receiving COVID-19 vaccines. While causality has not yet been established increased awareness and early recognition of the disorder would be crucial for the optimal management of these patients.

Herpes zoster following BNT162b2 mRNA Covid-19 vaccination in patients with autoimmune inflammatory rheumatic diseases: a case series

Objectives

As global vaccination campaigns against COVID-19 disease commence, vaccine safety needs to be closely assessed. The safety profile of mRNA-based vaccines in patients with autoimmune inflammatory rheumatic diseases (AIIRD) is unknown. The objective of this report is to raise awareness to reactivation of herpes zoster (HZ) following the BNT162b2 mRNA vaccination in patients with AIIRD.

Methods

The safety of the BNT162b2 mRNA vaccination was assessed in an observational study monitoring post-vaccination adverse effects in patients with AIIRD (n = 491) and controls (n = 99), conducted in two Rheumatology Departments in Israel.

Results

The prevalence of HZ was 1.2% (n = 6) in patients with AIIRD compared with none in controls. Six female patients aged 49 ± 11 years with stable AIIRD: rheumatoid arthritis (n = 4), Sjogren’s syndrome (n = 1), and undifferentiated connective disease (n = 1), developed the first in a lifetime event of HZ within a short time after the first vaccine dose in 5 cases and after the second vaccine dose in one case. In the majority of cases, HZ infection was mild, except a case of HZ ophthalmicus, without corneal involvement, in RA patient treated with tofacitinib. There were no cases of disseminated HZ disease or postherpetic neuralgia. All but one patient received antiviral treatment with a resolution of HZ-related symptoms up to 6 weeks. Five patients completed the second vaccine dose without other adverse effects.

Conclusion

Epidemiologic studies on the safety of the mRNA-based COVID-19 vaccines in patients with AIIRD are needed to clarify the association between the BNT162b2 mRNA vaccination and reactivation of zoster.

Evasion of Intracellular DNA Sensing by Human Herpesviruses

Sensing of viral constituents is the first and critical step in the host innate immune defense against viruses. In mammalian cells, there are a variety of pathogen recognition receptors (PRRs) that detect diverse pathogen-associated molecular patterns (PAMPs) including viral RNA and DNA. In the past decade, a number of host DNA sensors have been discovered and the underlying sensing mechanisms have been elucidated. Herpesviruses belong to a large family of enveloped DNA viruses. They are successful pathogens whose elaborate immune evasion mechanisms contribute to high prevalence of infection among their hosts. The three subfamilies of herpesviruses have all been found to employ diverse and overlapping strategies to interfere with host DNA sensing. These strategies include masking viral DNA or the DNA sensor, degradation of the DNA sensor, and post-transcriptional modification of the DNA sensor or its adaptor protein. In this review, we will discuss the current state of our knowledge on how human herpesviruses use these strategies to evade DNA-induced immune responses. Comprehensive understanding of herpesvirus immune-evasion mechanisms will aid in the development of vaccines and antivirals for herpesvirus-associated diseases.

Host Innate Immune Response and Viral Immune Evasion During Alphaherpesvirus Infection

Both the development of the mammalian innate immune system and the antagonistic strategies acquired by alphaherpesviruses to dismantle it have been shaped by co-evolving virus-host interactions over millions of years. Here, we review mechanisms employed by mammalian cells to detect pathogen molecules, such as viral glycoproteins and nucleic acids, and induce innate immune signaling upon infection with alphaherpesviruses. We further explore strategies acquired by these viruses to bypass immune detection and activation, thereby supporting virus replication and spread. Finally, we discuss the contributions of advanced 'omics' and microscopy methods to these discoveries in immune signaling and highlight emerging technologies that can help to further our understanding of the dynamic interplay between host innate immune responses and virus immune evasion.

Modulation of the Innate Immune Response by Targeting Toll-like Receptors: A Perspective on Their Agonists and Antagonists

Toll-like receptors (TLRs) are a class of proteins that recognize pathogen-associated molecular patterns (PAMPs) and damaged-associated molecular patterns (DAMPs), and they are involved in the regulation of innate immune system. These transmembrane receptors, localized at the cellular or endosomal membrane, trigger inflammatory processes through either myeloid differentiation primary response 88 (MyD88) or TIR-domain-containing adapter-inducing interferon-β (TRIF) signaling pathways. In the last decades, extensive research has been performed on TLR modulators and their therapeutic implication under several pathological conditions, spanning from infections to cancer, from metabolic disorders to neurodegeneration and autoimmune diseases. This Perspective will highlight the recent discoveries in this field, emphasizing the role of TLRs in different diseases and the therapeutic effect of their natural and synthetic modulators, and it will discuss insights for the future exploitation of TLR modulators in human health.

Mechanisms of Virus-Induced Airway Immunity Dysfunction in the Pathogenesis of COPD Disease, Progression, and Exacerbation

Chronic obstructive pulmonary disease (COPD) is the integrated form of chronic obstructive bronchitis and pulmonary emphysema, characterized by persistent small airway inflammation and progressive irreversible airflow limitation. COPD is characterized by acute pulmonary exacerbations and associated accelerated lung function decline, hospitalization, readmission and an increased risk of mortality, leading to huge social-economic burdens. Recent evidence suggests ~50% of COPD acute exacerbations are connected with a range of respiratory viral infections. Nevertheless, respiratory viral infections have been linked to the severity and frequency of exacerbations and virus-induced secondary bacterial infections often result in a synergistic decline of lung function and longer hospitalization. Here, we review current advances in understanding the cellular and molecular mechanisms underlying the pathogenesis of COPD and the increased susceptibility to virus-induced exacerbations and associated immune dysfunction in patients with COPD. The multiple immune regulators and inflammatory signaling pathways known to be involved in host-virus responses are discussed. As respiratory viruses primarily target airway epithelial cells, virus-induced inflammatory responses in airway epithelium are of particular focus. Targeting virus-induced inflammatory pathways in airway epithelial cells such as Toll like receptors (TLRs), interferons, inflammasomes, or direct blockade of virus entry and replication may represent attractive future therapeutic targets with improved efficacy. Elucidation of the cellular and molecular mechanisms of virus infections in COPD pathogenesis will undoubtedly facilitate the development of these potential novel therapies that may attenuate the relentless progression of this heterogeneous and complex disease and reduce morbidity and mortality.

Immunomodulatory roles of human herpesvirus-encoded microRNA in host-virus interaction

Human herpesviruses (HHV) are large, double stranded, DNA viruses with high seroprevalence across the globe. Clinical manifestation of primary HHV infection resolve shortly, however, this period is prolonged in immunocompromised patients or individuals with suppressed immunity. Examining molecular mechanisms of HHV-encoded virulence factors can provide finer details of HHV-host interaction. A unique genetic feature of most members of HHV is that they encode multiple microRNAs (miR). In this review, I will provide mechanistic insights into the immunomodulatory functions of herpesvirus-encoded viral miR (v-miR) that favor viral persistence and spread by ingenious immune evasion schemes. Similar to host miR, v-miR can simultaneously regulate expression of multiple transcripts including host- and virus-derived. V-miRs, by virtue of their direct interaction with various transcripts, can regulate expression of critical components of host innate and adaptive immune system. V-miRs are also exported through exosomal route and gain entry into various cells even at distant sites, thereby allowing HHV to manipulate cellular and tissue immunity. Targeting v-miR may serve as a novel and promising therapeutic candidate to mitigate HHV-mediated clinical manifestations.

N-methyl-D-aspartate receptor antibody production from germinal center reactions: Therapeutic implications

Introduction

N‐methyl‐D‐aspartate receptor (NMDAR) antibody encephalitis is mediated by immunoglobulin G (IgG) autoantibodies directed against the NR1 subunit of the NMDAR. Around 20% of patients have an underlying ovarian teratoma, and the condition responds to early immunotherapies and ovarian teratoma removal. However, despite clear therapeutic relevance, mechanisms of NR1‐IgG production and the contribution of germinal center B cells to NR1‐IgG levels are unknown.

Methods

Clinical data and longitudinal paired serum NR1‐reactive IgM and IgG levels from 10 patients with NMDAR‐antibody encephalitis were determined. Peripheral blood mononuclear cells from these 10 patients, and two available ovarian teratomas, were stimulated with combinations of immune factors and tested for secretion of total IgG and NR1‐specific antibodies.

Results

In addition to disease‐defining NR1‐IgG, serum NR1‐IgM was found in 6 of 10 patients. NR1‐IgM levels were typically highest around disease onset and detected for several months into the disease course. Moreover, circulating patient B cells were differentiated into CD19⁺CD27⁺⁺CD38⁺⁺ antibody‐secreting cells in vitro and, from 90% of patients, secreted NR1‐IgM and NR1‐IgG. Secreted levels of NR1‐IgG correlated with serum NR1‐IgG (p < 0.0001), and this was observed across the varying disease durations, suggestive of an ongoing process. Furthermore, ovarian teratoma tissue contained infiltrating lymphocytes which produced NR1‐IgG in culture.

Interpretation

Serum NR1‐IgM and NR1‐IgG, alongside the consistent production of NR1‐IgG from circulating B cells and from ovarian teratomas suggest that ongoing germinal center reactions may account for the peripheral cell populations which secrete NR1‐IgG. Cells participating in germinal center reactions might be a therapeutic target for the treatment of NMDAR‐antibody encephalitis. Ann Neurol 2018;83:553–561

Endosomal Toll-Like Receptors 7 and 9 Cooperate in Detection of Murine Gammaherpesvirus 68 Infection

Murine gammaherpesvirus 68 (MHV68) is a small-animal model suitable for study of the human pathogens Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus. Here, we have characterized the roles of the endosomal Toll-like receptor (TLR) escort protein UNC93B, endosomal TLR7, -9, and -13, and cell surface TLR2 in MHV68 detection. We found that the alpha interferon (IFN-α) response of plasmacytoid dendritic cells (pDC) to MHV68 was reduced in Tlr9-/- cells compared to levels in wild type (WT) cells but not completely lost. Tlr7-/- pDC responded similarly to WT. However, we found that in Unc93b-/- pDC, as well as in Tlr7-/-Tlr9-/- double-knockout pDC, the IFN-α response to MHV68 was completely abolished. Thus, the only pattern recognition receptors contributing to the IFN-α response to MHV68 in pDC are TLR7 and TLR9, but the contribution of TLR7 is masked by the presence of TLR9. To address the role of UNC93B and TLR for MHV68 infection in vivo, we infected mice with MHV68. Lytic replication of MHV68 after intravenous infection was enhanced in the lungs, spleen, and liver of UNC93B-deficient mice, in the spleen of TLR9-deficient mice, and in the liver and spleen of Tlr7-/-Tlr9-/- mice. The absence of TLR2 or TLR13 did not affect lytic viral titers. We then compared reactivation of MHV68 from latently infected WT, Unc93b-/-, Tlr7-/-Tlr9-/-, Tlr7-/-, and Tlr9-/- splenocytes. We observed enhanced reactivation and latent viral loads, particularly from Tlr7-/-Tlr9-/- splenocytes compared to levels in the WT. Our data show that UNC93B-dependent TLR7 and TLR9 cooperate in and contribute to detection and control of MHV68 infection.IMPORTANCE The two human gammaherpesviruses, Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV), can cause aggressive forms of cancer. These herpesviruses are strictly host specific, and therefore the homolog murine gammaherpesvirus 68 (MHV68) is a widely used model to obtain in vivo insights into the interaction between these two gammaherpesviruses and their host. Like EBV and KSHV, MHV68 establishes lifelong latency in B cells. The innate immune system serves as one of the first lines of host defense, with pattern recognition receptors such as the Toll-like receptors playing a crucial role in mounting a potent antiviral immune response to various pathogens. Here, we shed light on a yet unanticipated role of Toll-like receptor 7 in the recognition of MHV68 in a subset of immune cells called plasmacytoid dendritic cells, as well as on the control of this virus in its host.

The clinical features, underlying immunology, and treatment of autoantibody-mediated movement disorders

An increasing number of movement disorders are associated with autoantibodies. Many of these autoantibodies target the extracellular domain of neuronal surface proteins and associate with highly specific phenotypes, suggesting they have pathogenic potential. Below, we describe the phenotypes associated with some of these commoner autoantibody‐mediated movement disorders, and outline increasingly well‐established mechanisms of autoantibody pathogenicity which include antigen downregulation and complement fixation. Despite these advances, and the increasingly robust evidence for improved clinical outcomes with early escalation of immunotherapies, the underlying cellular immunology of these conditions has received little attention. Therefore, here, we outline the likely roles of T cells and B cells in the generation of autoantibodies, and reflect on how these may guide both current immunotherapy regimes and our future understanding of precision medicine in the field. In addition, we summarise potential mechanisms by which these peripherally‐driven immune responses may reach the central nervous system. We integrate this with the immunologically‐relevant clinical observations of preceding infections, tumours and human leucocyte antigen‐associations to provide an overview of the therapeutically‐relevant underlying adaptive immunology in the autoantibody‐mediated movement disorders. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Caspase-Dependent Suppression of Type I Interferon Signaling Promotes Kaposi's Sarcoma-Associated Herpesvirus Lytic Replication

An important component of lytic infection by Kaposi's sarcoma-associated herpesvirus (KSHV) is the ability of the virus to evade the innate immune response, specifically type I interferon (IFN) responses that are triggered by recognition of viral nucleic acids. Inhibition of type I IFN responses by the virus promotes viral replication. Here, we report that KSHV uses a caspase-dependent mechanism to block type I IFN, in particular IFN-β, responses during lytic infection. Inhibition of caspases during KSHV reactivation resulted in increased TBK1/IKKε-dependent phosphorylation of IRF3 as well as elevated levels of IFN-β transcription and secretion. The increased secretion of IFN-β upon caspase inhibition reduced viral gene expression, viral DNA replication, and virus production. Blocking IFN-β production or signaling restored viral replication. Overall, our results show that caspase-mediated regulation of pathogen sensing machinery is an important mechanism exploited by KSHV to evade innate immune responses.IMPORTANCE KSHV is the causative agent of Kaposi's sarcoma (KS), an AIDS-defining tumor that is one of the most common causes of cancer death in sub-Saharan Africa. In this study, we examined the role of a set of cellular proteases, called caspases, in the regulation of immune responses during KSHV infection. We demonstrate that caspases prevent the induction and secretion of the antiviral factor IFN-β during replicative KSHV infection. The reduced IFN-β production allows for high viral gene expression and viral replication. Therefore, caspases are important for maintaining KSHV replication. Overall, our results suggest that KSHV utilizes caspases to evade innate immune responses, and that inhibiting caspases could boost the innate immune response to this pathogen and potentially be a new antiviral strategy.

The cGAS-STING Defense Pathway and Its Counteraction by Viruses

Upon virus infection, host cells mount a concerted innate immune response involving type I interferon and pro-inflammatory cytokines to enable elimination of the pathogen. Recently, cGAS and STING have been identified as intracellular sensors that activate the interferon pathway in response to virus infection and thus mediate host defense against a range of DNA and RNA viruses. Here we review how viruses are sensed by the cGAS-STING signaling pathway as well as how viruses modulate this pathway. Mechanisms utilized by viral proteins to inhibit cGAS and/or STING are also discussed. On the flip side, host cells have also evolved strategies to thwart viral immune escape. The balance between host immune control and viral immune evasion is pivotal to viral pathogenesis, and we discuss this virus-host stand-off in the context of the cGAS-STING innate immune pathway.

Modulation of the cGAS-STING DNA sensing pathway by gammaherpesviruses

Infection of cells with DNA viruses triggers innate immune responses mediated by DNA sensors. cGMP-AMP synthase (cGAS) is a key DNA sensor that produces the cyclic dinucleotide cGMP-AMP (cGAMP) upon activation, which binds to and activates stimulator of interferon genes (STING), leading to IFN production and an antiviral response. Kaposi's sarcoma-associated herpesvirus (KSHV) is a DNA virus that is linked to several human malignancies. We report that KSHV infection activates the cGAS-STING pathway, and that cGAS and STING also play an important role in regulating KSHV reactivation from latency. We screened KSHV proteins for their ability to inhibit this pathway and identified six viral proteins that block IFN-β activation through this pathway. This study is the first report identifying multiple viral proteins encoded by a human DNA virus that inhibit the cGAS-STING DNA sensing pathway. One such protein, viral interferon regulatory factor 1 (vIRF1), targets STING by preventing it from interacting with TANK binding kinase 1 (TBK1), thereby inhibiting STING's phosphorylation and concomitant activation, resulting in an inhibition of the DNA sensing pathway. Our data provide a unique mechanism for the negative regulation of STING-mediated DNA sensing. Moreover, the depletion of vIRF1 in the context of KSHV infection prevented efficient viral reactivation and replication, and increased the host IFN response to KSHV. The vIRF1-expressing cells also inhibited IFN-β production following infection with DNA pathogens. Collectively, our results demonstrate that gammaherpesviruses encode inhibitors that block cGAS-STING-mediated antiviral immunity, and that modulation of this pathway is important for viral transmission and the lifelong persistence of herpesviruses in the human population.

What lies within: coinfections and immunity

Helminth-induced immunomodulation is thought to influence the outcome of secondary infections. Osborne et al. (2014) and Reese et al. (2014) demonstrate that helminth infection impacts viral infections by tilting the immune system toward Th2/M2 immune regulatory responses that dampen Th1/M1 antiviral responses as well as promote reactivation of latent herpesviruses.

Equine herpesvirus type 1 pUL56 modulates innate responses of airway epithelial cells

Recently, the product of equine herpesvirus type 1 (EHV-1) ORF1, a homolog to HSV-1 pUL56, was shown to modulate MHC-I expression and innate immunity. Here, we investigated modulation of respiratory epithelial immunity by EHV-1 pUL56 and compared responses to those of PBMCs, which are important target cells that allow cell-associated EHV-1 viremia. The salient observations are as follows: (i) EHV-1 significantly down-modulated MHC-I and MHC-II expression in equine respiratory epithelial cells (ERECs). MHC-I expression remained unaffected in PBMCs and MHC-II expression was increased. (ii) Infection with an EHV-1 ORF1 deletion mutant partially restored MHC-I and MHC-II expression and altered IFN-alpha and IL-10 mRNA expression. (iii) Deletion of EHV-1 ORF1 also significantly increased chemokine expression and chemotaxis of monocytes and neutrophils in ERECs. Collectively, these results suggest a role for EHV-1 pUL56 in modulation of antigen presentation, cytokine expression and chemotaxis at the respiratory epithelium, but not in PBMC.

Activation of NF-κB via endosomal Toll-like receptor 7 (TLR7) or TLR9 suppresses murine herpesvirus 68 reactivation

In order to understand and possibly treat B-cell malignancies associated with latent gammaherpesvirus infection, it is vital to understand the factors that control the balance between the two transcriptional states of gammaherpesviruses: latency and lytic replication. We used murine gammaherpesvirus 68 (MHV 68) as a model system to investigate how engagement of endosomal Toll-like receptors (TLRs) impacts reactivation from latency in vitro and establishment of latent infection in vivo. We found that treatment with TLR7 ligand R848 or TLR9 ligand CpG oligodeoxynucleotide (ODN) suppresses reactivation of MHV 68 in vitro. These suppressive effects correlated with the ability to activate cellular transcription factor NF-κB. Downregulation of TLR9 by RNA interference in vitro led to a reduction of nuclear levels of NF-κB p65 and consequently to an increase of spontaneous reactivation in cells latently infected with MHV 68, indicating that the TLR9 pathway suppresses spontaneous reactivation events. In vivo, sustained stimulation of TLR7 by repeated R848 treatment led to an increased frequency of infected splenocytes compared to mock-treated control results. Frequencies of infected splenic B cells in tlr7-/- or tlr9-/- mice after establishment of latency did not differ from those seen with their wild-type counterparts. Nevertheless, MHV 68-infected B cells from tlr9-/- mice showed a higher frequency of reactivation than B cells from wild-type or tlr7-/- mice in ex vivo reactivation assays. Thus, we show a suppressive effect of TLR7 or TLR9 triggering on MHV 68 reactivation that correlates with NF-κB activation and that the mere presence of a functional TLR9 signaling pathway contributes to dampen lytic gammaherpesvirus reactivation in infected cells.

IMPORTANCE

A hallmark of gammaherpesviruses is their establishment of latency in B cells that is reversible through lytic reactivation. Latency can result in B-cell malignancies. Activation of the innate immune system is thought to contribute to controlling the switch between the transcriptional states of latency and reactivation. Nevertheless, the mechanisms involved are not clear. Here, we show that engagement of Toll-like receptor 7 (TLR7) and TLR9 suppresses reactivation of murine gammaherpesvirus MHV 68 in vitro and that stimulation of TLR7 in vivo increases the frequency of infected cells. TLR7 and TLR9 are innate immunity sensors of nucleic acids localized in endosomes. Additionally, we demonstrate that impairment of TLR9 signaling in latently infected B cells leads to increased reactivation. Thus, activated endosomal TLR7 and TLR9 pathways play an important role in promoting establishment of latent gammaherpesvirus infection. Counteracting signaling of these pathways allows reactivation and could represent treatment targets in gammaherpesvirus-associated malignancies.