Anti-cytokine autoantibodies in postherpetic neuralgia

Identifying and Evaluating Biological Markers of Postherpetic Neuralgia: A Comprehensive Review

Postherpetic neuralgia (PHN) manifests as persistent chronic pain that emerges after a herpes zoster outbreak and greatly diminishes quality of life. Unfortunately, its treatment efficacy has remained elusive, with many therapeutic efforts yielding less than satisfactory results. The research to discern risk factors predicting the onset, trajectory, and prognosis of PHN has been extensive. However, these risk factors often present as nonspecific and diverse, indicating the need for more reliable, measurable, and objective detection methods. The exploration of potential biological markers, including hematological indices, pathological insights, and supportive tests, is increasing. This review highlights potential biomarkers that are instrumental for the diagnosis, management, and prognosis of PHN while also delving deeper into its genesis. Drawing from prior research, aspects such as immune responsiveness, neuronal injury, genetic makeup, cellular metabolism, and pain signal modulation have emerged as prospective biomarkers. The immune spectrum spans various cell subtypes, with an emphasis on T cells, interferons, interleukins, and other related cytokines. Studies on nerve injury are directed toward pain-related proteins and the density and health of epidermal nerve fibers. On the genetic and metabolic fronts, the focus lies in the detection of predisposition genes, atypical protein manifestations, and energy-processing dynamics, with a keen interest in vitamin metabolism. Tools such as functional magnetic resonance imaging, electromyography, and infrared imaging have come to the forefront in the pain signaling domain. This review compiles the evidence, potential clinical implications, and challenges associated with these promising biomarkers, paving the way for innovative strategies for predicting, diagnosing, and addressing PHN.

Unraveling the Immune Signature of Herpes Zoster: Insights Into the Pathophysiology and Human Leukocyte Antigen Risk Profile

The varicella-zoster virus (VZV) infects >95% of the population. VZV reactivation causes herpes zoster (HZ), known as shingles, primarily affecting the elderly and individuals who are immunocompromised. However, HZ can occur in otherwise healthy individuals. We analyzed the immune signature and risk profile in patients with HZ using a genome-wide association study across different UK Biobank HZ cohorts. Additionally, we conducted one of the largest HZ human leukocyte antigen association studies to date, coupled with transcriptomic analysis of pathways underlying HZ susceptibility. Our findings highlight the significance of the major histocompatibility complex locus for HZ development, identifying 5 protective and 4 risk human leukocyte antigen alleles. This demonstrates that HZ susceptibility is largely governed by variations in the major histocompatibility complex. Furthermore, functional analyses revealed the upregulation of type I interferon and adaptive immune responses. These findings provide fresh molecular insights into the pathophysiology and activation of innate and adaptive immune responses triggered by symptomatic VZV reactivation.

Loss of tolerance precedes triggering and lifelong persistence of pathogenic type I interferon autoantibodies

Autoantibodies neutralizing type I interferons (IFN-Is) can underlie infection severity. Here, we trace the development of these autoantibodies at high-resolution using longitudinal samples from 1,876 well-treated individuals living with HIV over a 35-year period. Similar to general populations, ∼1.9% of individuals acquired anti-IFN-I autoantibodies as they aged (median onset ∼63 years). Once detected, anti-IFN-I autoantibodies persisted lifelong, and titers increased over decades. Individuals developed distinct neutralizing and non-neutralizing autoantibody repertoires at discrete times that selectively targeted combinations of IFNα, IFNβ, and IFNω. Emergence of neutralizing anti-IFNα autoantibodies correlated with reduced baseline IFN-stimulated gene levels and was associated with subsequent susceptibility to severe COVID-19 several years later. Retrospective measurements revealed enrichment of pre-existing autoreactivity against other autoantigens in individuals who later developed anti-IFN-I autoantibodies, and there was evidence for prior viral infections or increased IFN at the time of anti-IFN-I autoantibody triggering. These analyses suggest that age-related loss of self-tolerance prior to IFN-I immune-triggering poses a risk of developing lifelong functional IFN-I deficiency.

Impact of Herpes Zoster and Postherpetic Neuralgia on the Quality of Life in China: A Prospective Study

Background

Herpes zoster (HZ) and postherpetic neuralgia (PHN) significantly affect patients' quality of life (QoL). Cultural differences may lead to different patient-reported outcomes across countries. The current study aims to evaluate the detrimental impact of HZ and PHN on QoL in China.

Methods

This prospective study was conducted from January 2020 to April 2023. We used the Zoster Brief Pain Inventory (ZBPI) and 5-level EuroQol-5 Dimension (EQ-5D-5L) questionnaire to assess the QoL of HZ and PHN patients. Patients were required to complete the questionnaires at 15, 30, 60, and 90 days after the onset of the HZ rash. Additional questionnaires were administered at 120, 150, and 180 days for those who developed PHN within three months of the rash's onset.

Results

A cohort of 633 patients with a median age of 63 years were included in the study. The mean delay from the appearance of the initial HZ rash to the first medical consultation was 5.1 ± 2.8 days. Approximately 30% of the HZ patients (189/633) went on to develop PHN. For patients with HZ who did not progress to PHN, the ZBPI worst pain score and impaired QoL had nearly resolved by day 90 post-rash onset. Conversely, there was no significant improvement in the ZBPI worst pain score and QoL for those with PHN, even by day 180 post-rash onset.

Conclusion

Both HZ and PHN significantly impaired patients' QoL. However, the impairment caused by PHN was more severe in both intensity and duration.

Anti-cytokine autoantibodies: mechanistic insights and disease associations

Anti-cytokine autoantibodies (ACAAs) are increasingly recognized as modulating disease severity in infection, inflammation and autoimmunity. By reducing or augmenting cytokine signalling pathways or by altering the half-life of cytokines in the circulation, ACAAs can be either pathogenic or disease ameliorating. The origins of ACAAs remain unclear. Here, we focus on the most common ACAAs in the context of disease groups with similar characteristics. We review the emerging genetic and environmental factors that are thought to drive their production. We also describe how the profiling of ACAAs should be considered for the early diagnosis, active monitoring, treatment or sub-phenotyping of diseases. Finally, we discuss how understanding the biology of naturally occurring ACAAs can guide therapeutic strategies.

Human autoantibodies neutralizing type I IFNs: From 1981 to 2023

Human autoantibodies (auto-Abs) neutralizing type I IFNs were first discovered in a woman with disseminated shingles and were described by Ion Gresser from 1981 to 1984. They have since been found in patients with diverse conditions and are even used as a diagnostic criterion in patients with autoimmune polyendocrinopathy syndrome type 1 (APS-1). However, their apparent lack of association with viral diseases, including shingles, led to wide acceptance of the conclusion that they had no pathological consequences. This perception began to change in 2020, when they were found to underlie about 15% of cases of critical COVID-19 pneumonia. They have since been shown to underlie other severe viral diseases, including 5%, 20%, and 40% of cases of critical influenza pneumonia, critical MERS pneumonia, and West Nile virus encephalitis, respectively. They also seem to be associated with shingles in various settings. These auto-Abs are present in all age groups of the general population, but their frequency increases with age to reach at least 5% in the elderly. We estimate that at least 100 million people worldwide carry auto-Abs neutralizing type I IFNs. Here, we briefly review the history of the study of these auto-Abs, focusing particularly on their known causes and consequences.

Anticytokine Autoantibodies in Infectious Diseases: A Practical Overview

Anticytokine autoantibodies (ACAAs) are a fascinating group of antibodies that have gained more and more attention in the field of autoimmunity and secondary immunodeficiencies over the years. Some of these antibodies are characterized by their ability to target and neutralize specific cytokines. ACAAs can play a role in the susceptibility to several infectious diseases, and their infectious manifestations depending on which specific immunological pathway is affected. In this review, we will give an outline per infection in which ACAAs might play a role and whether additional immunomodulatory treatment next to antimicrobial treatment can be considered. Finally, we describe the areas for future research on ACAAs.

Pathophysiology, Clinical Implications and Management of Orofacial Neuropathic Pain- with special attention to Trigeminal neuralgia: A Narrative Review

Background: It is a widely held belief that if the trigeminal nerve is damaged, the victim would experience agonising and unrelenting external pain. A lesion to the trigeminal nerve may have a wide-reaching effect, such as on one side of the face in particular, or it might have a more localised effect, such as on some or all of your gums. The risk of damage increases the likelihood that it will be difficult to speak and swallow. This nerve provides sensation to a part of your face that may be constantly aching or tingling for some people. However, the trigeminal nerve injury-related persistent orofacial pain might be brought on by a wide variety of unknown triggers. Aim: In this study investigate the clinical manifestations of chronic orofacial pain brought on by a damage to the trigeminal nerve, as well as the diagnostic and therapeutic approaches available to treat this condition. Methodology Through the use of search phrases such as "Trigeminal nerve injury," "Trigeminal ganglion," "Trigeminal spinal subnucleus caudalis," "Craniofacial pain," "Oral prognosis," and "treatment," the computerised databases for the last twenty years have been investigated. There are now two hundred objects in total that have been accumulated. There have been around fifty of them that are pertinent to the discussion that is going on in this work. Majority of the patients fair enough with the pharmacology treatment/drugs like the carbamazepine & oxcarbazepine which forms the first line treatment options followed by lamotrigine & baclofen encompassing the second line of drugs along with adjuvant drug support of topiramate, levetiracetam, gabapentin, pregabalin. As the field of science has explored &advanced for the latest treatment options include microvascular decompression, gamma knife radiosurgery, percutaneous rhizotomies variable based on the evidences & guidelines 54 Conclusion: New diagnostic criteria and treatment alternatives have become available for people who suffer from trigeminal neuropathy and orofacial neuropathic pain as a result of recent developments in fundamental animal research that have led to their development. Despite the results, more research needs to investigate a greater variety of distinct non-neuronal cell feature approaches.

Autoantibodies to Interferons in Infectious Diseases

Anti-cytokine autoantibodies and, in particular, anti-type I interferons are increasingly described in association with immunodeficient, autoimmune, and immune-dysregulated conditions. Their presence in otherwise healthy individuals may result in a phenotype characterized by a predisposition to infections with several agents. For instance, anti-type I interferon autoantibodies are implicated in Coronavirus Disease 19 (COVID-19) pathogenesis and found preferentially in patients with critical disease. However, autoantibodies were also described in the serum of patients with viral, bacterial, and fungal infections not associated with COVID-19. In this review, we provide an overview of anti-cytokine autoantibodies identified to date and their clinical associations; we also discuss whether they can act as enemies or friends, i.e., are capable of acting in a beneficial or harmful way, and if they may be linked to gender or immunosenescence. Understanding the mechanisms underlying the production of autoantibodies could improve the approach to treating some infections, focusing not only on pathogens, but also on the possibility of a low degree of autoimmunity in patients.

T Lymphocyte Subsets Profile and Toll-Like Receptors Responses in Patients with Herpes Zoster

Purpose

Herpes zoster (HZ) is caused by the varicella-zoster virus (VZV), and 20% of healthy humans and 50% of people with immune dysfunction have a high probability of suffering from HZ. This study aimed to screen dynamic immune signatures and explore the potential mechanism during HZ progression.

Patients and Methods

Peripheral blood samples from 31 HZ patients and 32 age-sex-matched healthy controls were collected and analyzed. The protein levels and gene levels of toll-like receptors (TLRs) were detected in peripheral blood mononuclear cells (PBMCs) by flow cytometry and quantitative real-time PCR. Further, the characteristics of T cell subsets and cytokines were detected via a cytometric bead array.

Results

Compared to healthy controls, the mRNA levels of TLR2, TLR4, TLR7, and TLR9 mRNA in PBMCs were significantly increased in HZ patients. The protein level of TLR4 and TLR7 was significantly increased in HZ patients, but the levels of TLR2 and TLR9 were dramatically decreased. The CD3+ T cells were constant in HZ and healthy controls. CD4+ T cells were decreased in HZ patients, while CD8+ T cells were increased, resulting in an improved CD4+/CD8+ T cells ratio. Further, it was found that Th2 and Th17 were not changed, but the decreased Th1 and upregulated Treg cells were found in HZ. The Th1/Th2 and Th17/Treg ratios were significantly decreased. Last, the levels of IL-6, IL-10, and IFN-γ were significantly increased, but IL-2, IL-4, and IL-17A had no significant changes.

Conclusion

The dysfunction of host's lymphocytes and activation of TLRs in PBMCs were the important mechanism in varicella-zoster virus induced herpes zoster. TLRs might be the core targets for the therapy drug development in treating HZ.

Increased risk of psoriasis: An immune sequela of herpes zoster? Evidence from a nationwide population-based cohort study

BACKGROUND

Several cases of herpes zoster-induced psoriasis have been reported in the literature.

OBJECTIVE

Our nationwide retrospective cohort study is designed to examine the risk association between herpes zoster and psoriasis.

METHODS

From the Taiwan National Health Insurance Research Database, 26,623 patients from 1999 to 2013 with a diagnosis of herpes zoster and no prior history of psoriasis were selected as the study subjects. The control group was established during the study period from those without a herpes zoster diagnosis and was propensity score matched to minimize confounding factors. Both cohorts were followed for cases of psoriasis development. Data analysis was done via Kaplan-Meier analysis and Cox Proportional-Hazards Models.

RESULTS

Comparing the study group to control, the adjusted hazard ratio was 1.66 (95% CI, 1.31-2.13: p < 0.05) after adjusting for covariates (age, gender, urbanization, selected comorbidities and selected medications use). Statistical analysis found no interaction effect among herpes zoster and other covariates for risk modification of psoriasis development.

CONCLUSION

This study demonstrated an increased risk of psoriasis in patients diagnosed with herpes zoster.

Anticytokine autoantibodies: Autoimmunity trespassing on antimicrobial immunity

Anticytokine autoantibodies can cause immunodeficiency or dysregulate immune responses. They may phenocopy genetically defined primary immunodeficiencies. We review current anti-type 1 and anti-type 2 interferon; anti-IL-12/23, anti-IL-17, and anti-GM-CSF autoantibodies; HLA associations; disease associations; and mechanistically based treatment options. Suspecting the presence of these autoantibodies in patients and identifying them at the onset of symptoms should ameliorate disease and improve outcomes.

The Role of GM-CSF Autoantibodies in Infection and Autoimmune Pulmonary Alveolar Proteinosis: A Concise Review

Autoantibodies to multiple cytokines have been identified and some, including antibodies against granulocyte-macrophage colony-stimulating factor (GM-CSF), have been associated with increased susceptibility to infection. High levels of GM-CSF autoantibodies that neutralize signaling cause autoimmune pulmonary alveolar proteinosis (aPAP), an ultrarare autoimmune disease characterized by accumulation of excess surfactant in the alveoli, leading to pulmonary insufficiency. Defective GM-CSF signaling leads to functional deficits in multiple cell types, including macrophages and neutrophils, with impaired phagocytosis and host immune responses against pulmonary and systemic infections. In this article, we review the role of GM-CSF in aPAP pathogenesis and pulmonary homeostasis along with the increased incidence of infections (particularly opportunistic infections). Therefore, recombinant human GM-CSF products may have potential for treatment of aPAP and possibly other infectious and pulmonary diseases due to its pleotropic immunomodulatory actions.

Recent Issues in Varicella-Zoster Virus Latency

Varicella-zoster virus (VZV) is a human herpes virus which causes varicella (chicken pox) as a primary infection, and, following a variable period of latency in neurons in the peripheral ganglia, may reactivate to cause herpes zoster (shingles) as well as a variety of neurological syndromes. In this overview we consider some recent issues in alphaherpesvirus latency with special focus on VZV ganglionic latency. A key question is the nature and extent of viral gene transcription during viral latency. While it is known that this is highly restricted, it is only recently that the very high degree of that restriction has been clarified, with both VZV gene 63-encoded transcripts and discovery of a novel VZV transcript (VLT) that maps antisense to the viral transactivator gene 61. It has also emerged in recent years that there is significant epigenetic regulation of VZV gene transcription, and the mechanisms underlying this are complex and being unraveled. The last few years has also seen an increased interest in the immunological aspects of VZV latency and reactivation, in particular from the perspective of inborn errors of host immunity that predispose to different VZV reactivation syndromes.

Immunological mechanism of postherpetic neuralgia and effect of pregabalin treatment on the mechanism: a prospective single-arm observational study

BACKGROUND

Although neuropathic pain is a severe and common pain, its pathophysiology has not been elucidated yet. Studies in recent years have focused on the immune system's role in the pathogenesis of neuropathic pain. The aim of this study was to investigate the role of immunological mechanisms in neuropathic pain and the effect of pregabalin by measuring immunological marker levels in peripheral blood before and after pregabalin treatment in postherpetic neuralgia (PHN) patients with neuropathic pain.

METHODS

Forty patients diagnosed with PHN were included in the study. CD4, T follicular cells (Tfh: CD4+CXCR5+PD1+), Th17 (CD4+CCR6+ and CD4+IL17A+), regulatory T cells (Treg: CD4+ CD25+foxp3+), Th1 (CD4+ CXCR3+ and CD4+ IFN-γ+) and Th2 (CD4+ IL-4+) cell ratios were measured in peripheral blood samples before treatment and after 3 months of treatment.

RESULTS

When immunological marker and inflammation parameter levels were compared before and after treatment, the helper T cell ratio (CD3+, CD4+) was 30.28 ± 12.27% before treatment and 34.93 ± 11.70% after treatment, so there was a statistically significant increase (P = 0.028). Th17 was 4.75 ± 5.02% before treatment and 5.80 ± 3.13% after treatment, and there was a statistically significant increase (P = 0.036).

CONCLUSIONS

Immunological mechanisms play an essential role in the pathogenesis of neuropathic pain, immunologically based treatment approach will be the critical point of treatment.

Patients with autoimmune polyendocrine syndrome type 1 have an increased susceptibility to severe herpesvirus infections

Almost all patients with autoimmune polyendocrine syndrome type 1 (APS-1) have neutralizing antibodies against type 1 interferons (IFN), important mediators of antiviral defense. Recently, neutralizing anti-IFN antibodies were shown to be a risk factor of severe COVID-19. Here we show in a cohort of 44 patients with APS-1 that higher titers of neutralizing anti-IFNα4 antibodies are associated with a higher and earlier incidence of VZV reactivation (herpes zoster). The patients also present with uncommonly severe clinical sequelae of herpetic infections. APS-1 patients had decreased humoral immune responses to varicella zoster virus, but cellular responses were comparable to healthy controls. These results suggest that blocking the type I interferon pathway in patients with APS-1 patients leads to a clinically significant immune deficiency, and susceptibility to herpesviruses should be taken into account when treating patients with APS-1.

Orofacial Neuropathic Pain-Basic Research and Their Clinical Relevancies

Trigeminal nerve injury is known to cause severe persistent pain in the orofacial region. This pain is difficult to diagnose and treat. Recently, many animal studies have reported that rewiring of the peripheral and central nervous systems, non-neuronal cell activation, and up- and down-regulation of various molecules in non-neuronal cells are involved in the development of this pain following trigeminal nerve injury. However, there are many unknown mechanisms underlying the persistent orofacial pain associated with trigeminal nerve injury. In this review, we address recent animal data regarding the involvement of various molecules in the communication of neuronal and non-neuronal cells and examine the possible involvement of ascending pathways in processing pathological orofacial pain. We also address the clinical observations of persistent orofacial pain associated with trigeminal nerve injury and clinical approaches to their diagnosis and treatment.

Primary and Acquired Immunodeficiencies Associated with Severe Varicella-Zoster Infections

BACKGROUND

While most cases of varicella or zoster are self-limited, patients with certain immune deficiencies may develop severe or life-threatening disease.

METHODS

We studied a patient with varicella-zoster virus (VZV) CNS vasculopathy and as part of the evaluation, tested his plasma for antibodies to cytokines. We reviewed the literature for cases of varicella or zoster associated with primary and acquired immunodeficiencies.

RESULTS

We found that a patient with VZV CNS vasculopathy had antibody that neutralized interferon (IFN)-α, but not IFN-γ. The patient's plasma blocked phosphorylation in response to stimulation with IFN-α in healthy control peripheral blood mononuclear cells. In addition to acquired immunodeficiencies like HIV or autoantibodies to IFN, variants in specific genes have been associated with severe varicella and/or zoster. While these genes encode proteins with very different activities, many affect IFN signaling pathways, either those that sense double-stranded RNA or cytoplasmic DNA that trigger IFN production, or those involved in activation of IFN stimulated genes in response to binding of IFN with its receptor.

CONCLUSIONS

Immune deficiencies highlight the critical role of IFN in control of VZV infections and suggest new approaches for treatment of VZV infection in patients with certain immune deficiencies.

Clinical features of Sjögren's syndrome patients with autoantibodies against interferons

Background

Sjögren’s syndrome (SS) is an autoimmune disease characterized by immune attack on the salivary and lacrimal glands. Given the known cytokine activation and type I interferon gene expression signature found in SS, we hypothesized that anticytokine autoantibodies might be detectable by Luciferase immunoprecipitation systems in some SS patients and correlate with clinical symptoms.

Results

Luciferase immunoprecipitation systems was used to screen for serum anti-cytokine autoantibodies in 57 primary SS patients and 25 healthy volunteers. Autoantibodies were detected against GMCSF, interferon-γ, -α and, -ω in one, two, two and six patients with SS, respectively. None of the healthy volunteers showed anticytokine autoantibodies and none of the SS or control subjects showed autoantibodies against interferon-λ. One 51-year old female SS subject with the highest anti-interferon-α and -ω autoantibody levels had stable autoantibody levels over the course of a year. In vitro functional testing of serum autoantibodies from this subject demonstrated partially neutralizing activity for interferon-α signaling. Clinical information on this individual revealed a low focus score and high levels of unstimulated salivary flow, suggesting the possibility that interferon-α autoantibody neutralizing activity may have contributed to the milder sicca symptoms.

Conclusion

Overall, these findings demonstrate that a subset of SS patients (16%) harbor autoantibodies against GMCSF, interferon-γ, interferon-ω, and interferon-α. These data support the observation that high levels of interferon-α autoantibodies may attenuate disease symptoms in SS.

Combined therapy of pulsed radiofrequency and nerve block in postherpetic neuralgia patients: a randomized clinical trial

Caused by viral infection, postherpetic neuralgia (PHN) is the most common chronic neuropathic pain. Various treatment modalities such as early use of nerve block therapy (NBT) and pulsed radiofrequency (PRF) have been studied in reducing pain, however, no consistent success was achieved in all the patients treated with single regimen. The combined therapy of PRF and NBT with different targeting mechanism are of interest and remains to be determined. Here we investigated the combined effects of pulsed radiofrequency (PRF) with nerve block therapy (NBT) in PHN patients in a prospective randomized clinical trial. Sixty PHN patients were divided into four groups (n = 15 each): the conventional puncture group (group CP), the nerve block therapy group (group NB), the PRF group (group PRF), and the combined treatment group (PRF combined with nerve block therapy (group CT). To evaluate the extent of remission of hyperalgesia, we recorded the visual analogue scale (VAS) scores during cotton swab reaction before and after treatment and in the resting and active pain states. In addition, blood samples were collected and plasma cytokine and neuropeptides such as interleukin-6 (IL-6), substance P (SP), and β-endorphin (β-EP) were measured by enzyme-linked immunosorbent assay (ELISA) at the admission (basic state), before the operation, and at 12 h postoperatively. The number of adverse events (nausea, vomiting, constipation, puncture point hemorrhage, swelling and redness) within 12 h of the treatment were also documented. Our results showed that VAS scores during cotton swab reaction decreased after treatment in all patients (p < 0.05). Compared to group CP, plasma IL-6 and SP levels decreased (p < 0.05) and β-EP levels increased (p < 0.05) in groups NB, PRF, and CT. There were no significant differences in adverse events among groups (p > 0.05). We found that PRF in combination with NBT increased β-EP levels and decreased plasma IL-6 and SP, thereby alleviating pain and hyperalgesia in PHN patients. Taken together, our data suggest combined therapy of PRF and NBT is effective and safe for PHN patients.

Cellular Stress Response to Varicella-Zoster Virus Infection of Human Skin Includes Highly Elevated Interleukin-6 Expression

Background

The infectious cycle of varicella-zoster virus (VZV) after reactivation from the dorsal root ganglia includes replication and assembly of complete enveloped virions in the human skin to cause the characteristic herpes zoster (shingles).

Methods

To pursue studies of innate immunity to VZV infection, we have adapted a fetal skin organ culture model to a human neonatal foreskin explant model.

Results

Abundant expression of VZV IE62, gE, and gC was visualized by confocal microscopy while numerous enveloped virions were observed by electron microscopy in infected skin organ cultures. Microarray experiments demonstrated that the patterns of upregulated transcripts differed between VZV-infected cells and VZV-infected skin explants. One result stood out, namely a >30-fold elevated interleukin (IL)-6 level in the infected skin explant that was not present in the infected monolayer culture. The IL-6 results in the polyermase chain reaction (PCR) assay were reproduced by quantitative PCR testing with newly designed primers. To determine if increased transcription was accompanied by increased IL-6 expression, we quantitated the levels of IL-6 protein in the explant media at increasing intervals after infection. We found a statistically significant increase in IL-6 protein levels secreted into the media from VZV-infected skin explants as compared with mock-infected explants.

Conclusions

The cellular stress response to VZV infection in neonatal skin explants included highly elevated levels of IL-6 transcription and expression. This skin organ model could be adapted to other viruses with a skin tropism, such as herpes simplex virus.

Electrophysiological characteristics of the frontal nerve in patients with herpetic ophthalmic neuralgia

INTRODUCTION

The aim of this study was to explore a method for obtaining sensory nerve action potentials (SNAPs) of the supratrochlear (STN) and supraorbital (SON) nerves and evaluate the function of affected nerves in patients with herpetic ophthalmic neuralgia (HON).

METHODS

Thirty healthy volunteers and 40 subjects with subacute HON participated in this study.

RESULTS

The amplitudes and sensory conduction velocities (SCVs) that predicted HON were identified. The corresponding cutoff values for the amplitudes ranged from 11.10 μV to 12.45 μV. The corresponding cutoff values for the SCVs ranged from 43.14 m/s to 44.64 m/s. SCVs were markedly lower on the affected side compared with healthy volunteers (P < 0.05), and the amplitudes of SNAPs on the affected side were decreased by 36% compared with healthy volunteers (P < 0.05).

DISCUSSION

SCVs of STN and SONs can be obtained with the 3-channel method and used to evaluate myelinated fibers in patients with HON. Muscle Nerve 57: 973-980, 2018.

Postherpetic Neuralgia and Trigeminal Neuralgia

Postherpetic neuralgia (PHN) is an unpredictable complication of varicella zoster virus- (VZV-) induced herpes zoster (HZ) which often occurs in elderly and immunocompromised persons and which can induce psychosocial dysfunction and can negatively impact on quality of life. Preventive options for PHN include vaccination of high-risk persons against HZ, early use of antiviral agents, and robust management of pain during the early stage of acute herpes zoster. If it does occur, PHN may persist for months or even years after resolution of the HZ mucocutaneous eruptions, and treatment is often only partially effective. Classical trigeminal neuralgia is a severe orofacial neuropathic pain condition characterized by unilateral, brief but recurrent, lancinating paroxysmal pain confined to the distribution of one or more of the branches of the trigeminal nerve. It may be idiopathic or causally associated with vascular compression of the trigeminal nerve root. The anticonvulsive agents, carbamazepine or oxcarbazepine, constitute the first-line treatment. Microvascular decompression or ablative procedures should be considered when pharmacotherapy is ineffective or intolerable. The aim of this short review is briefly to discuss the etiopathogenesis, clinical features, and treatment of PHN and classical trigeminal neuralgia.

Post-herpetic neuralgia - a review of current management and future directions

Post-herpetic neuralgia (PHN) is common and treatment is often suboptimal with less than half of patients achieving adequate 50% pain relief. As an area of unmet clinical need and as an archetype of neuropathic pain, it deserves the attention of clinicians and researchers. Areas covered: This review summarises the epidemiology, pathophysiology, risk factors and clinical features of varicella infection. It describes the current and possible future management strategies for preventing varicella infection and reactivation and for treating PHN. Expert opinion: A highly successful Varicella Zoster (VZV) vaccine has not been universally adopted due to fears that it may increase Herpes Zoster (HZ) incidence - and thus PHN - in older, unvaccinated generations. This is a controversial theory but advances in the efficacy of vaccines against HZ may allay these fears and encourage more widespread adoption of the VZV vaccine. Treatment of PHN, as for any neuropathic pain, must be multidisciplinary and multimodal. Advances in sensory phenotyping technology and genomics may allow more individualised treatment. Traditional research methodologies are ill-suited to assess the kind of complex interventions that are necessary to achieve better clinical outcomes in this challenging field.