Immunohistochemical identification of varicella-zoster virus gene 63-encoded protein (IE63) and late (gE) protein on smears and cutaneous biopsies: implications for diagnostic use

Herpes zoster in neuro-ophthalmology: a practical approach

Herpes Zoster (HZ) or shingles is the reactivation of the Varicella Zoster Virus (VZV), usually along a single sensory nerve, but can affect both sensory and motor cranial nerves. Major risk factors for HZ include immunosuppressed status and age older than 60 years. In the United States, the lifetime risk of HZ is approximately 30%. Worldwide, the median incidence of HZ is 4-4.5 per 1000 person-years across the Americas, Eurasia, and Australia. HZ ophthalmicus, occurring in 10-20% of patients, is an ophthalmic emergency characterized by VZV reactivation along the V1 branch of the trigeminal nerve. Approximately half of this patient subgroup will go on to develop ocular manifestations, requiring prompt diagnosis and management. While anterior segment complications are more common, neuro-ophthalmic manifestations are rarer and can also occur outside the context of overt HZ ophthalmicus. Neuro-ophthalmic manifestations include optic neuropathy, acute retinal necrosis or progressive outer retinal necrosis, cranial neuropathy (isolated or multiple), orbitopathy, and CNS manifestations. Although typically a clinical diagnosis, diagnosis may be aided by neuroimaging and laboratory (e.g., PCR and serology) studies. Early antiviral therapy is indicated as soon as a presumptive diagnosis of VZV is made and the role of corticosteroids remains debated. Generally, there is wide variation of prognosis with neuro-ophthalmic involvement. Vaccine-mediated prevention is recommended. In this review, we summarize neuro-ophthalmic manifestations of VZV.

A Review of Atypical Cutaneous Histological Manifestations of Herpes Zoster

The clinical and histopathological features of herpes zoster (HZ) are usually straightforward. Atypical histological presentations, in the absence of the classical viral cytopathic changes, are well documented and can make the diagnosis of HZ extremely difficult. Herein, we review the existing literature on atypical cutaneous histological manifestations of the disease, with emphasis on the subtle clues, use of immunohistochemistry, and potential pitfalls.

Varicella-zoster virus in actively spreading segmental vitiligo skin: Pathological, immunochemical, and ultrastructural findings (a first and preliminary study)

Segmental vitiligo (SV) is a unilateral subtype of vitiligo which is clinically characterized by a cutaneous depigmentation and histologically by a melanocyte loss from the epidermis and hair follicle reservoirs. To date, its pathogenesis remains a mystery. In many cases, this skin depigmentation shares several clinical features and dysfunctions with herpes zoster (HZ). So, for the first time, we examined whether any nucleus and cell fusion associated with a positive immunolabelling of varicella-zoster virus (VZV) and VZV mature virions could be found in SV skin samples as in herpes zoster (HZ). A total of 40 SV samples were used for histological and immunochemical studies. Control samples were obtained from three HZ, and 10 generalized vitiligo lesions. For ultrastructural study, three recent SV and one HZ as controls were recruited. Here, we report that nuclear fusion in epidermal cells were statistically associated with recent SV (p < .001), whereas syncytia formation was associated with long-lasting SV (p = .001). A positive detection of VZV antigen was statistically associated in the epidermis with recent SV and in the dermis with long-lasting SV (p = .001). Finally, the discovery of mature virions in 3/3 recent SV samples provides additional arguments for our viral hypothesis.

Immunohistochemical diagnosis of human infectious diseases: a review

BACKGROUND

Immunohistochemistry (IHC) using monoclonal and polyclonal antibodies is a useful diagnostic method for detecting pathogen antigens in fixed tissues, complementing the direct diagnosis of infectious diseases by PCR and culture on fresh tissues. It was first implemented in a seminal publication by Albert Coons in 1941.

MAIN BODY

Of 14,198 publications retrieved from the PubMed, Google, Google Scholar and Science Direct databases up to December 2021, 230 were selected for a review of IHC techniques, protocols and results. The methodological evolutions of IHC and its application to the diagnosis of infectious diseases, more specifically lice-borne diseases, sexually transmitted diseases and skin infections, were critically examined. A total of 59 different pathogens have been detected once in 22 different tissues and organs; and yet non-cultured, fastidious and intracellular pathogens accounted for the vast majority of pathogens detected by IHC. Auto-IHC, incorporating patient serum as the primary antibody, applied to diseased heart valves surgically collected from blood culture-negative endocarditis patients, detected unidentified Gram-positive cocci and microorganisms which were subsequently identified as Coxiella burnetii, Bartonella quintana, Bartonella henselae and Tropheryma whipplei. The application of IHC to ancient tissues dated between the ends of the Ptolemaic period to over 70 years ago, have also contributed to paleomicrobiology diagnoses.

CONCLUSION

IHC plays an important role in diagnostic of infectious diseases in tissue samples. Paleo-auto-IHC derived from auto-IHC, is under development for detecting non-identified pathogens from ancient specimens.

Neurological and Ophthalmological Manifestations of Varicella Zoster Virus

BACKGROUND

Approximately 1 million new cases of herpes zoster (HZ) occur in the United States annually, including 10%-20% with herpes zoster ophthalmicus (HZO). Postherpetic neuralgia, a debilitating pain syndrome occurs in 30% HZ, whereas 50% HZO develop ophthalmic complications. Diplopia from cranial nerve palsy occurs in less than 30% HZO, whereas optic neuropathy is seen in less than 1% HZO. We reviewed recent developments in the diagnosis, treatment, and prevention of HZ as well as neurological and ophthalmological complications of relevance to the neuro-ophthalmologist.

EVIDENCE ACQUISITION

We searched the English language literature on Pubmed and Google scholar for articles relevant to the various sections of this review.

RESULTS

Antiviral treatment should be initiated within 48-72 hours of onset of HZ and HZO to decrease pain and reduce complications. We recommend neuroimaging in all patients with neuro-ophthalmic manifestations such as diplopia and acute vision loss. Diagnostic confirmation using polymerase chain reaction and serology on paired serum and cerebrospinal fluid samples should be obtained in those with neurological signs and symptoms or abnormal imaging. Patients with neurological and/or retinal varicella zoster virus (VZV) infection should be treated promptly with intravenous acyclovir. Patients with isolated optic neuropathy or cranial nerve palsy can be managed with oral antivirals. The prognosis for visual recovery is good for patients with isolated optic neuropathy and excellent for patients with isolated ocular motor cranial nerve palsy.

CONCLUSIONS

HZ produces a spectrum of potentially blinding and life-threatening complications that adversely affect quality of life and increase health care costs. Individuals at risk for HZ, such as the elderly and immunocompromised, should be encouraged to receive the highly effective VZV vaccine to prevent HZ and its complications.

Comprehensive analysis of varicella-zoster virus proteins using a new monoclonal antibody collection

Varicella-zoster virus (VZV) is the etiological agent of chickenpox and shingles. Due to the virus's restricted host and cell type tropism and the lack of tools for VZV proteomics, it is one of the least-characterized human herpesviruses. We generated 251 monoclonal antibodies (MAbs) against 59 of the 71 (83%) currently known unique VZV proteins to characterize VZV protein expression in vitro and in situ. Using this new set of MAbs, 44 viral proteins were detected by Western blotting (WB) and indirect immunofluorescence (IF); 13 were detected by WB only, and 2 were detected by IF only. A large proportion of viral proteins was analyzed for the first time in the context of virus infection. Our study revealed the subcellular localization of 46 proteins, 14 of which were analyzed in detail by confocal microscopy. Seven viral proteins were analyzed in time course experiments and showed a cascade-like temporal gene expression pattern similar to those of other herpesviruses. Furthermore, selected MAbs tested positive on human skin lesions by using immunohistochemistry, demonstrating the wide applicability of the MAb collection. Finally, a significant portion of the VZV-specific antibodies reacted with orthologs of simian varicella virus (SVV), thus enabling the systematic analysis of varicella in a nonhuman primate model system. In summary, this study provides insight into the potential function of numerous VZV proteins and novel tools to systematically study VZV and SVV pathogenesis.

Phenotypic analysis of human CD4+ T cells specific for immediate-early 63 protein of varicella-zoster virus

Open reading frame 63 of varicella-zoster Virus (VZV) encodes an immediate early (IE) phosphoprotein (IE63) that is believed to be important for viral infectivity and establishing latency. Evidence suggests that VZV-specific T cells are crucial in the control of viral replication; however, data addressing the existence of IE63 protein-specific CD4+ T cells are limited. Using IFN-gamma immunosorbent assays, we identified high frequencies of responses to overlapping peptides spanning the IE63 protein both ex vivo and after in vitro restimulation in healthy VZV-seropositive individuals. We identified a commonly recognised epitope, restricted by HLA-DRB1*1501, which was naturally processed and presented by keratinocytes. We proceeded to investigate the frequency and phenotype of the epitope-specific CD4+ T cells using HLA class II tetrameric complexes. Epitope-specific CD4+ T cells were detectable ex vivo and showed a mixed central and effector-memory differentiation phenotype, with a significant proportion showing evidence of recent activation and rapid effector function. In summary these data implicate persistent low-level or recurrent VZV antigen exposure in healthy immune donors and are compatible with a role for IE63-specific CD4+ T cells in the control of viral reactivation.

Absence of intercellular adhesion molecule 1 expression in varicella zoster virus-infected keratinocytes during herpes zoster: another immune evasion strategy?

Downregulation of major histocompatibility complex (MHC) class I, MHC-II, and intercellular adhesion molecule 1 (ICAM-1) expression in infected cell lines allows some viruses to escape host immunity. In skin lesions of varicella zoster virus (VZV), MHC-II transcripts were demonstrated in keratinocytes around vesicles, but not in VZV-infected cells. Whether other immunoevasive mechanisms are present during herpes zoster (HZ) is not yet elucidated. The aim of the study was to disclose the temporal immunohistochemical expression of immune escape mechanisms during HZ. Sequential skin biopsies were performed in 5 HZ patients. VZV IE63, CD1a, CD3, CD4, CD8, CD56, CD68, L1, HLA-DR, HLA-ABC, interleukin (IL)-6, IL-10, interferon gamma (IFNgamma), tumor necrosis factor alpha (TNFalpha), and ICAM-1 expressions were assessed on frozen sections using immunohistochemistry. Controls consisted of normal skin, herpes simplex virus (HSV) skin infections, and other distinct bullous skin diseases. HLA-DR and ICAM-1 expressions were not observed in VZV- and HSV-infected keratinocytes, contrasting with their upregulation in the surrounding epidermis and inside nonviral blisters. However, HLA-ABC expressions were not inhibited in VZV-infected keratinocytes. Furthermore, the CD4/CD8 ratio remained unmodified during the infection evolution, and this ratio was variable among patients. Increased IFNgamma, TNFalpha, and IL-6 expressions were present, but IL-10 expression only increased in later stages. In contrast to in vitro MHC-I and MHC-II downregulation, VZV infection is related to MHC-II but not MHC-I expression on infected keratinocytes. The absence of ICAM-1 expression on infected keratinocytes may reduce their antigen presentation capacities to LFA-1 ligand-bearing T cells. This may represent another VZV-associated immune escape mechanism. Increased IFNgamma, TNFalpha, and IL-6 expressions suggest a TH1 profile.

Revisiting childhood herpes zoster

Herpes zoster is rare in otherwise healthy children, but it is more common in association with immunosuppression. Maternal varicella infection during pregnancy and varicella occurring in the newborn represent risk factors for childhood herpes zoster. However, some controversies persist about risk factors, diagnosis, and the natural history of childhood disease. In a 2-year prospective study, 18 children with herpes zoster were clinically diagnosed in outpatient consultations in a hospital dermatology unit. Data about age, dermatome involvement, underlying disease, and history of previous varicella were recorded. Tzanck smears, biopsy specimens, and sera were obtained from 18, 4, and 10 children, respectively. The varicella zoster virus major envelope glycoprotein gE was detected in 16 of 18 smears and all four biopsies. Herpes simplex virus I was demonstrated in one of the smears. The established risk factors for childhood herpes zoster were only found in one child. Evidence for previous full-blown varicella and varicella with few lesions was recorded in 7 and 4 of the 17 immunocompetent children, respectively. No history of varicella was recalled in 6 of 17 cases, although a serologic clue of past varicella infection (IgM negative, IgG positive) was disclosed. Recurrent herpes zoster was diagnosed in one immunocompromised child. Zoster-associated pain was localized and the disease severity remained mild in all children. Established risk factors for childhood herpes zoster were only rarely found in our series of patients. In contrast, unrecognized varicella and varicella with few lesions were frequently recorded and may represent additional risk factors for shingles in childhood. Zosteriform herpes simplex virus infections should be differentiated from childhood herpes zoster, emphasizing the importance of precise viral identification.

Memory cytotoxic T cell responses to viral tegument and regulatory proteins encoded by open reading frames 4, 10, 29, and 62 of varicella-zoster virus

Cytotoxic T cell recognition of tegument and regulatory proteins encoded by open reading frames (ORFs) 4, 10, 29, and 62 of varicella-zoster virus (VZV) was evaluated using limiting dilution conditions to estimate the precursor frequencies of memory T cells specific for these proteins in immune subjects. Responder cell frequencies for ORFs 4, 10, and 62 gene products, which are virion tegument components and function as immediate early viral transactivating proteins, were equivalent. CTLp recognition of VZV proteins made in latently infected cells, which include ORF4 and ORF62 proteins, was not maintained preferentially when compared to ORF10 protein, which has not been shown to be expressed during latency. T cell recognition of ORF29 protein, the major DNA binding protein, which is expressed during replication but not incorporated into the virion tegument, was less common than responses to ORFs 4, 10, and 62 gene products. Older individuals had diminished numbers of memory CTLp that lysed autologous targets expressing IE62 protein; these responses were increased after immunization with live attenuated varicella vaccine to the range observed in younger adults. Adaptive immunity to VZV is characterized by a broad repertoire of memory CTL responses to proteins that comprise the virion tegument and regulate viral gene expression in infected cells.

Atypical recurrent varicella in 4 patients with hemopathies

Relapsing varicella may occur in children with HIV infection and more rarely in younger adults. Our aim was to report unusual clinical, histologic, and virologic aspects of 4 elderly patients with malignant hemopathies who had an unusual form of recurrent varicella develop. Conventional microscopy, immunohistochemistry, and in situ hybridization were applied to smears and skin biopsy specimens. The patients presented a few dozen, scattered, large, papulovesicular lesions with central crusting. No zoster-associated pain or dermatomal distribution of the lesions was noted. Conventional microscopy revealed vascular changes and epidermal alterations typical for alpha-herpes virus infection. The varicella zoster virus major viral envelope glycoproteins gE and gB, and the immediate-early varicella zoster virus IE63 protein and the corresponding genome sequence for gE were detected on Tzanck smears; they were localized in endothelial cells and keratinocytes on skin biopsy specimens. The varicella zoster virus infection in endothelial cells, the vascular involvement, and the widespread distribution of the lesions suggest that the reported eruptions are vascular rather than neural in origin. These findings invalidate the diagnosis of herpes zoster but strongly support the diagnosis of recurrent varicella in an indolent and yet unreported presentation. Furthermore, these eruptions differ from relapsing varicella in children and young adults by the age of the patients, the paucity of clinical lesions, the larger diameter of the lesions and their peculiar clinical aspect, the significantly longer time interval between primary varicella and the recurrence, the prolonged healing time of the lesions, their mild disease course, and the fact that all the lesions are in the same stage of development.

Immunogenicity of a recombinant varicella-zoster virus gE-IE63 fusion protein, a putative vaccine candidate against primary infection and zoster reactivation

The varicella-zoster virus (VZV) envelope glycoprotein E (gE) and immediate early protein 63 (IE63) are well known targets for specific humoral and cell-mediated immune responses during VZV infection and latency, respectively. The present study evaluated the immunogenicity of an engineered chimeric recombinant gE-IE63 (recgE-IE63) protein secreted from CHO cells, wherein a soluble form of gE, deleted of its anchor and cytoplasmic domains was fused to IE63. Guinea pig vaccinations with adjuvanted recgE-IE63 elicited a strong and specific humoral immune response directed to each counterpart. Sera from recgE-IE63-immunized animals neutralized cell-free VZV. This neutralizing capacity was dependent only on the recgE moiety as serum depletions on recgE-immobilized sepharose totally abolished VZV neutralization. The cell-mediated immune response induced by recgE-IE63 was evaluated in lymphoproliferation assays. An antigen-specific proliferative response was demonstrated after lymphocyte stimulation with recIE63 but not with recgE. We conclude that recombinant chimeric recgE-IE63 induced both humoral and cell-mediated immune responses and thus could constitute a putative subunit vaccine candidate against VZV primary infection and zoster reactivation.

Early diagnosis of herpes zoster by polymerase chain reaction

BACKGROUND

Herpes zoster is a common disease caused by the varicella-zoster virus. The use of virostatic agents as early as possible is necessary in shortening zoster-associated pain.

OBJECTIVES

Rapid diagnosis is necessary for the optimal efficacy of antiviral therapy. The diagnosis in the early stage of infection is often difficult.

METHODS

In the present study skin biopsies of patients with herpes zoster and unclear skin changes were analysed by detecting viral DNA using the polymerase chain reaction (PCR) in order to amplify open reading frames (ORF) 14, 29 and 63.

RESULTS

Varicella-zoster virus DNA could be detected with PCR of all three ORF not only from blisters but also from erythematous skin.

CONCLUSIONS

PCR is the method of choice for the viral diagnosis in herpes zoster before blister eruption.

[18F]-FDG uptake in soft tissue dermatome prior to herpes zoster eruption: an unusual pitfall

Authors report on a case of [18F]-fluorodeoxyglucose ([18F]-FDG) uptake in the soft tissue of a patient referred for [18F]-FDG coincidence detection emission tomography (CDET) in a search for recurrence of colorectal cancer. A herpes zoster eruption occurred in the same site within two days, but was spontaneously resolved. To the best of our knowledge this is the first description of a false positive [18F]-FDG result in relation to a viral infection of soft tissue. It shows that interpretation of subcutaneous foci has to be cautious in patients with or without a past history of herpes zoster even in pain-free areas and prior to skin eruption.

The role of varicella zoster virus immediate-early proteins in latency and their potential use as components of vaccines

Varicella zoster virus immediate-early (IE) proteins are intracellular regulators of viral gene expression. Some of them (IE62 and IE63) are found in large amounts in infected cells but are also components of the virion tegument. Several IE and early genes are transcribed during latency, while late genes are not. Recently, we demonstrated the presence of protein IE 63 in dorsal root ganglia of persistently infected rats as well as in normal human ganglia; other IE proteins have been found since in human ganglia. Cell-mediated immunity (CMI) to IE 62 has been evidenced. We found both humoral immunity and CMI to IE 63 in immune adults. In elderly zoster-free individuals, CMI to IE 63 remained high. The differences in the CMI to IE 63 among young adults, elderly people and immunocompromized patients have to be analyzed according to their status relative to zoster, to determine whether the decrease in CMI, particularly to IE proteins, could be responsible for viral reactivation and for the onset of shingles. Hopefully, the waning of the CMI to VZV IE 63 and perhaps to other IE proteins could become a predictive marker for herpes zoster and reimmunization, not only with the vaccine strain, but also with purified IE proteins could help prevent zoster at old age.

Longitudinal analysis of varicella-zoster virus DNA on the ocular surface associated with herpes zoster ophthalmicus

PURPOSE

Longitudinal analysis of varicella-zoster virus DNA on the ocular surface of patients with herpes zoster ophthalmicus.

METHODS

Clinical specimens were obtained from the bulbar conjunctival surface with a cotton-tipped swab at weekly intervals for 6 consecutive weeks from 21 patients with acute ophthalmic zoster with a skin rash duration of less than 7 days. All patients received oral valacyclovir 1000 mg three times daily for 10 days without additional corticosteroids. The swabs were analyzed by means of polymerase chain reaction for the presence of varicella-zoster virus and herpes simplex virus type 1 DNA. Conjunctival swabs were also obtained from a control group of 20 patients with cataract.

RESULTS

On inclusion, varicella-zoster virus DNA was present on the ocular surface of 19 of the 21 patients. Six varicella-zoster virus DNA-positive patients had no signs of ocular inflammation. All control swabs were negative for both varicella-zoster virus and herpes simplex virus DNA. The duration of varicella-zoster virus DNA detection from rash onset varied from 2 to 34 days. The number of days between the onset of herpes zoster skin rash and the latest positive varicella-zoster virus DNA test was significantly longer in patients whose age was equal to or above the median age of 66 years than in the younger patients (Mann-Whitney test: P =.0004). At 6-week follow-up, all conjunctival swabs were negative for varicella-zoster virus DNA. However, at that time, the eyes of seven patients were still inflamed.

CONCLUSION

The duration of varicella-zoster virus DNA shedding in herpes zoster ophthalmicus is highly variable and age dependent, and is probably related to the host immune response.

Chronic verrucous varicella zoster virus skin lesions: clinical, histological, molecular and therapeutic aspects

The outbreak of HIV infection introduced a new phenomenon in varicella zoster virus (VZV) pathology, namely the long-standing wart-like skin lesions that are frequently associated with resistance to thymidine kinase (TK)-dependent antiviral agents. This paper reviews the clinical, histological, and molecular aspects and the therapeutic management of these verrucous lesions. The majority of lesions are characterized by chronically evolving, unique or multiple wart-like cutaneous lesions. The main histopathological features include hyperkeratosis, verruciform acanthosis and VZV-induced cytopathic changes with scant or absent cytolysis of infected keratinocytes. The mechanism that establishes the chronic nature of the lesions appears to be associated with a particular pattern of VZV gene expression exhibiting reduced or nondetectable gE and gB synthesis. Drug resistance to TK-dependent antiviral agents is a result of nonfunctional or deficient viral TK. This necessitates alternative therapeutic management using antiviral agents that target the viral DNA polymerase.

Shingles developing within recent surgical scars

Occurrence of varicella and recurrence of herpes simplex on traumatized sites of the skin are well-described events. By contrast, herpes zoster occurring specifically at the site of previously injured skin has not yet been reported. Two patients are presented who developed shingles limited to skin on and around recent surgical scars. Varicella zoster virus was identified using immunohistochemistry on skin biopsy specimens and Tzanck smears. We suspect that the occurrence of herpes zoster involving surgical scars is usually misdiagnosed and therefore unrecognized. Whether shingles adjacent to scars represents a coincidental event or is specifically triggered by local injury is unknown.