Comparative immunohistochemical study of herpes simplex and varicella-zoster infections

Herpes simplex virus-induced murine dry skin model through sweating disturbance

BACKGROUND

Given that ocular glands become infected secondarily to herpes simplex virus 1 (HSV-1) keratitis, resulting in the loss of tear production, sweat glands may also be susceptible to HSV-1 infection, resulting in sweating disturbance, which is observed frequently in atopic dermatitis. However, due to the lack of sweat glands on the hairy skin of mice, the role of sweating in the maintenance of skin hydration has not been elucidated.

OBJECTIVE

To determine the relationship between HSV-1 infection of sweat glands and sweating disturbance-induced dry skin.

METHODS

By using the impression mold technique, we examined the sweating response together with the detection of HSV-1 DNA in the sweat glands of footpads, the only area with sweat glands in mice, after local cutaneous HSV-1 inoculation of immunocompetent mice.

RESULTS

The sweating response and skin surface hydration were significantly decreased at 7-14 days post-infection. Sweating disturbance and dry skin was markedly enhanced when HSV-1 inoculation was followed by hyperthermic stress. Both resolved spontaneously and became resistant to a second HSV-1 inoculation, associated with increased anti-HSV-IgG antibodies. HSV-1 DNA was detected in sweat glands and dorsal root ganglia. The sweating response remained decreased after subcutaneous injection with pilocarpine, correlating histologically with marked dilatation of sweat gland lumens. These findings indicate that sweating disturbance is unlikely to be the outcome of nerve damage by HSV-1 infection.

CONCLUSION

Sweating disturbance could be due to HSV-induced dysfunction of sweat glands. We developed a sweating disturbance-induced dry skin mouse model by infection with HSV-1.

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.

Incidence of and Risk Factors for Cutaneous Scarring after Herpes Zoster

BACKGROUND

About 20% of children have cutaneous scars following chickenpox. In contrast, skin scars are not often reported after herpes zoster (HZ). Risk factors for post-HZ scarring remain undetermined.

OBJECTIVE

Our objective was to prospectively study the incidence of and risk factors for post-HZ scarring.

METHODS

This was a 3-year prospective study of patients with HZ attending a tertiary university hospital. Baseline data, including age, sex, immunosuppression, prior history of scarring, severity and extension of HZ, afflicted HZ dermatome, and antiviral treatment received, were recorded. At 1 month after the HZ skin lesions had healed, patients were screened for skin scars at the prior HZ site. These patients were followed every 2 months for 6 months.

RESULTS

At 6 months, 11 (9.7%) of 113 HZ patients still had post-HZ scarring (fair-skinned patients: hypopigmented [n = 3], hyperpigmented [n = 2], atrophic cicatricial [n = 3], and hypertrophic cicatricial [n = 1]; dark-skinned patients: severe hyperpigmented hypertrophic scarring [n = 2]). HZ was extensive and severe in all cases. Nine of the 11 patients were immunocompromised. Three cases had a history of hypertrophic/keloid scarring but no post-varicella scars. The most frequent location was the trunk (n = 5), followed by the cervical region (n = 3) and the face (n = 3). Given the study setting, it is possible that immunocompromized patients with severe HZ were overrepresented in this study.

CONCLUSIONS

Scarring after HZ is probably overlooked. The principal risk factors seem to be severe HZ and immunosuppression. Hence, prompt instigation of antiviral treatment for HZ and HZ vaccination could help reduce the incidence of post-HZ scarring.

Atrophic scar formation in patients with acne involves long-acting immune responses with plasma cells and alteration of sebaceous glands

BACKGROUND

Possible outcomes of acne lesions are atrophic scars, which may cause serious psychological distress. Current treatments for postacne scarring often require invasive procedures. Pathophysiological studies on acne scarring have only investigated the first week of papule life.

OBJECTIVES

To study the pathophysiology of atrophic scar formation to identify molecular and cellular pathways that can lead to new therapies for the prevention of acne scarring.

METHODS

Large-scale gene expression profiling and immunohistochemistry analysis were performed on uninvolved skin and papules in both scar-prone (SP) and non-scar-prone (NSP) patients with acne, at different time points.

RESULTS

Gene expression and immunohistochemistry analyses showed a very similar immune response in 48-h-old papules in SP and NSP populations, characterized by elevated numbers of T cells, neutrophils and macrophages. However, the immune response only persisted in SP patients in 3-week-old papules, and was characterized by an important B-cell infiltrate. Transient downmodulation of sebaceous gland markers related to lipid metabolism was observed in 48-h-old papules in NSP patients, followed by normalization after 3 weeks. In contrast, in SP patients a drastic reduction of these markers persisted in 3-week-old papules, suggesting an irreversible destruction of sebaceous gland structures after inflammatory remodelling in SP patients with acne.

CONCLUSIONS

Long-lived acne papules are characterized by a B-cell infiltrate. A relationship exists between the duration and severity of inflammation and the alteration of sebaceous gland structures, leading to atrophic scar formation in acne.

Guillain-Barré syndrome, transverse myelitis and infectious diseases

Guillain-Barré syndrome (GBS) and transverse myelitis (TM) both represent immunologically mediated polyneuropathies of major clinical importance. Both are thought to have a genetic predisposition, but as of yet no specific genetic risk loci have been clearly defined. Both are considered autoimmune, but again the etiologies remain enigmatic. Both may be induced via molecular mimicry, particularly from infectious agents and vaccines, but clearly host factor and co-founding host responses will modulate disease susceptibility and natural history. GBS is an acute inflammatory immune-mediated polyradiculoneuropathy characterized by tingling, progressive weakness, autonomic dysfunction, and pain. Immune injury specifically takes place at the myelin sheath and related Schwann-cell components in acute inflammatory demyelinating polyneuropathy, whereas in acute motor axonal neuropathy membranes on the nerve axon (the axolemma) are the primary target for immune-related injury. Outbreaks of GBS have been reported, most frequently related to Campylobacter jejuni infection, however, other agents such as Zika Virus have been strongly associated. Patients with GBS related to infections frequently produce antibodies against human peripheral nerve gangliosides. In contrast, TM is an inflammatory disorder characterized by acute or subacute motor, sensory, and autonomic spinal cord dysfunction. There is interruption of ascending and descending neuroanatomical pathways on the transverse plane of the spinal cord similar to GBS. It has been suggested to be triggered by infectious agents and molecular mimicry. In this review, we will focus on the putative role of infectious agents as triggering factors of GBS and TM.

Subacute demyelinating polyradiculoneuropathy complicating Epstein-Barr virus infection in GATA2 haploinsufficiency

INTRODUCTION

Autosomal dominant haploinsufficiency of GATA2 causes monocytopenia and natural killer cell lymphopenia, resulting in predisposition to mycobacterial, fungal, and viral infections.

METHODS

Herein we report on the clinical, serologic, electrophysiologic, and pathologic evaluations of a 29-year-old woman with GATA2 haploinsufficiency and active Epstein-Barr virus (EBV) infection complicated by subacute painful neuropathy.

RESULTS

Nerve conduction and electromyography studies showed predominantly demyelinating sensorimotor polyradiculoneuropathy. Lumbar spine MRI showed thickening and enhancement of the cauda equina nerve roots. Serum and cerebrospinal fluid anti-IgG and IgM EBV capsid and nucleic acid antibodies were positive. Sural nerve biopsy showed microvasculitis and an increased frequency of fibers with segmental demyelination. Intravenous immunoglobulin and steroids improved the patient's neuropathy.

CONCLUSION

GATA2 mutation-related immunodeficiency may predispose to EBV-associated subacute demyelinating polyradiculoneuropathy by both viral susceptibility and immune dysregulation. In patients who present in this manner, immunodeficiency syndromes should be considered when lymphomatous infiltration is excluded. Immunotherapy can be helpful. Muscle Nerve 57: 150-156, 2018.

Dendritic cells as Achilles' heel and Trojan horse during varicella zoster virus infection

Varicella zoster virus (VZV), a human alphaherpesvirus, causes varicella and subsequently establishes latency within sensory nerve ganglia. Later in life VZV can reactivate to cause herpes zoster. A reduced frequency of VZV-specific T cells is strongly associated with herpes zoster illustrating that these immune cells are central to control latency. Dendritic cells (DCs) are required for the generation of VZV-specific T cells. However, DCs can also be infected in vitro and in vivo allowing VZV to evade the antiviral immune response. Thus, DCs represent the immune systems' Achilles heel. Uniquely among the human herpesviruses, VZV infects both DCs and T cells, and exploits both as Trojan horses. During primary infection VZV-infected DCs traffic to the draining lymph nodes and tonsils, where the virus is transferred to T cells. VZV-infected T cells subsequently spread infection throughout the body to give the typical varicella skin rash. The delicate interplay between VZV and DCs and its consequences for viral immune evasion and viral dissemination will be discussed in this article.

T-Cell tropism of simian varicella virus during primary infection

Varicella-zoster virus (VZV) causes varicella, establishes a life-long latent infection of ganglia and reactivates to cause herpes zoster. The cell types that transport VZV from the respiratory tract to skin and ganglia during primary infection are unknown. Clinical, pathological, virological and immunological features of simian varicella virus (SVV) infection of non-human primates parallel those of primary VZV infection in humans. To identify the host cell types involved in virus dissemination and pathology, we infected African green monkeys intratracheally with recombinant SVV expressing enhanced green fluorescent protein (SVV-EGFP) and with wild-type SVV (SVV-wt) as a control. The SVV-infected cell types and virus kinetics were determined by flow cytometry and immunohistochemistry, and virus culture and SVV-specific real-time PCR, respectively. All monkeys developed fever and skin rash. Except for pneumonitis, pathology produced by SVV-EGFP was less compared to SVV-wt. In lungs, SVV infected alveolar myeloid cells and T-cells. During viremia the virus preferentially infected memory T-cells, initially central memory T-cells and subsequently effector memory T-cells. In early non-vesicular stages of varicella, SVV was seen mainly in perivascular skin infiltrates composed of macrophages, dendritic cells, dendrocytes and memory T-cells, implicating hematogenous spread. In ganglia, SVV was found primarily in neurons and occasionally in memory T-cells adjacent to neurons. In conclusion, the data suggest the role of memory T-cells in disseminating SVV to its target organs during primary infection of its natural and immunocompetent host.

Varicella-zoster virus (VZV) causes varicella, establishes life-long latent infection in ganglia and reactivates later in life to cause zoster. VZV is acquired via the respiratory route, with skin rash occurring up to 3 weeks after exposure. The cell types that transport VZV to skin and ganglia during primary infection are unknown. Simian varicella virus (SVV) infection of non-human primates mimics clinical, pathological and immunological features of human VZV infection. African green monkeys were infected with recombinant SVV expressing enhanced green fluorescent protein (SVV-EGFP) or wild-type SVV (SVV-wt) as a control. By visualizing SVV-EGFP−infected cells in the living animal and in tissue samples, we identified the virus-infected cell types in blood, lungs, skin and ganglia during primary infection. Our data demonstrate that during viremia, SVV predominantly infects peripheral blood memory T-cells. Detection of SVV-infected memory T-cells in lungs, in early varicella skin lesions and also, albeit to a lesser extent, in ganglia suggests a role for memory T-cells in transporting virus to these organs. Our study provides novel insights into the cell types involved in virus dissemination and the overall pathology of varicella in a non-human primate model.

ORF9p phosphorylation by ORF47p is crucial for the formation and egress of varicella-zoster virus viral particles

The role of the tegument during the herpesvirus lytic cycle is still not clearly established, particularly at the late phase of infection, when the newly produced viral particles need to be fully assembled before being released from the infected cell. The varicella-zoster virus (VZV) protein coded by open reading frame (ORF) 9 (ORF9p) is an essential tegument protein, and, even though its mRNA is the most expressed during the productive infection, little is known about its functions. Using a GalK positive/negative selection technique, we modified a bacterial artificial chromosome (BAC) containing the complete VZV genome to create viruses expressing mutant versions of ORF9p. We showed that ORF9p is hyperphosphorylated during the infection, especially through its interaction with the viral Ser/Thr kinase ORF47p; we identified a consensus site within ORF9p recognized by ORF47p and demonstrated its importance for ORF9p phosphorylation. Strikingly, an ultrastructural analysis revealed that the mutation of this consensus site (glutamate 85 to arginine) strongly affects viral assembly and release, reproducing the ORF47 kinase-dead VZV phenotype. It also slightly diminishes the infectivity toward immature dendritic cells. Taken together, our results identify ORF9p as a new viral substrate of ORF47p and suggest a determinant role of this phosphorylation for viral infectivity, especially during the process of viral particle formation and egress.

The varicella-zoster virus ORF47 kinase interferes with host innate immune response by inhibiting the activation of IRF3

The innate immune response constitutes the first line of host defence that limits viral spread and plays an important role in the activation of adaptive immune response. Viral components are recognized by specific host pathogen recognition receptors triggering the activation of IRF3. IRF3, along with NF-κB, is a key regulator of IFN-β expression. Until now, the role of IRF3 in the activation of the innate immune response during Varicella-Zoster Virus (VZV) infection has been poorly studied. In this work, we demonstrated for the first time that VZV rapidly induces an atypical phosphorylation of IRF3 that is inhibitory since it prevents subsequent IRF3 homodimerization and induction of target genes. Using a mutant virus unable to express the viral kinase ORF47p, we demonstrated that (i) IRF3 slower-migrating form disappears; (ii) IRF3 is phosphorylated on serine 396 again and recovers the ability to form homodimers; (iii) amounts of IRF3 target genes such as IFN-β and ISG15 mRNA are greater than in cells infected with the wild-type virus; and (iv) IRF3 physically interacts with ORF47p. These data led us to hypothesize that the viral kinase ORF47p is involved in the atypical phosphorylation of IRF3 during VZV infection, which prevents its homodimerization and subsequent induction of target genes such as IFN-β and ISG15.

Viruses and Langerhans cells

Langerhans cells (LCs) are the resident dendritic cells (DCs) of epidermis in human mucosal stratified squamous epithelium and the skin. A phenotypically similar DC has recently been discovered as a minor population in the murine dermis. In epidermis, LCs function as sentinel antigen-presenting cells that can capture invading viruses such as herpes simplex virus (HSV), varicella-zoster virus (VZV) and human immunodeficiency virus (HIV). This interaction between LCs and viruses results in highly variable responses, depending on the virus as discussed in this review. For example, HSV induces apoptosis in LCs but HIV does not. LCs seem to be the first in a complex chain of antigen presentation to T cells in lymph nodes for HSV and possibly VZV, or they transport virus to T cells, as described for HIV and maybe VZV. Together with epidermal keratinocytes they may also have a role in the initial innate immune response at the site of infection in the epidermis, although this is not fully known. The full spectrum of biological responses of LCs even to these viruses has yet to be understood and will require complementary studies in human LCs in vitro and in murine models in vivo.

Impact of varicella-zoster virus on dendritic cell subsets in human skin during natural infection

Varicella-zoster virus (VZV) causes varicella and herpes zoster, diseases characterized by distinct cutaneous rashes. Dendritic cells (DC) are essential for inducing antiviral immune responses; however, the contribution of DC subsets to immune control during natural cutaneous VZV infection has not been investigated. Immunostaining showed that compared to normal skin, the proportion of cells expressing DC-SIGN (a dermal DC marker) or DC-LAMP and CD83 (mature DC markers) were not significantly altered in infected skin. In contrast, the frequency of Langerhans cells was significantly decreased in VZV-infected skin, whereas there was an influx of plasmacytoid DC, a potent secretor of type I interferon (IFN). Langerhans cells and plasmacytoid DC in infected skin were closely associated with VZV antigen-positive cells, and some Langerhans cells and plasmacytoid DC were VZV antigen positive. To extend these in vivo observations, both plasmacytoid DC (PDC) isolated from human blood and Langerhans cells derived from MUTZ-3 cells were shown to be permissive to VZV infection. In VZV-infected PDC cultures, significant induction of alpha IFN (IFN-alpha) did not occur, indicating the VZV inhibits the capacity of PDC to induce expression of this host defense cytokine. This study defines changes in the response of DC which occur during cutaneous VZV infection and implicates infection of DC subtypes in VZV pathogenesis.

Occult varicella

BACKGROUND

Localized varicella has been associated with UV-exposure and skin trauma. Varicella restricted to a pre-existent dermatitis is exceptional.

OBJECTIVES

The clinical features, cytohistologic and immunohistochemical results, as well as serologic data of 6 patients with a sudden eruption of vesicular and eroded lesions restricted to a pre-existent dermatitis are presented.

RESULTS

All patients (mean age: 8,3 years, range: 3-22) showed crops of a few to numerous vesicular lesions clustered on the restricted sites of posttraumatic wound, perianal streptococcal dermatitis, dermatomycosis, allergic contact dermatitis, lichen sclerosus, and atopic foot dermatitis. All the Tzanck smears and 1 biopsy revealed multinucleated giant cells, consistent with herpes simplex virus (HSV) or varicella zoster virus (VZV) infection. Immunohistochemistry using specific anti-VZV antibodies (IE63 and gE) was positive on all the smears and the biopsy, whereas HSV-I and HSV-II immunolabeling was negative. VZV specific IgM+, IgG- EIA-based serology, and positive VZV-specific IgM complement fixation test suggested primary VZV infection. None had received varicella vaccine. None of the patients presented a history of varicella nor experienced breakthrough varicella. It was decided not to administer antiviral treatment, as the varicella lesions remained localized without any further skin extension and systemic signs. About 2 months later, EIA-serology revealed positive VZV-IgG and negative IgM levels in 5/5 patients.

CONCLUSION

Some patients have varicella infection that remains hidden in a pre-existent infectious and/or inflammatory dermatitis without ever presenting full-blown chickenpox. The sudden occurrence of vesicular and/or ulcerated lesions on a pre-existent dermatitis should prompt searching for a viral infection.

Occult herpes simplex virus colonization of bullous dermatitides

BACKGROUND

Acantholytic disorders, including pemphigus vulgaris, chronic benign familial pemphigus (Hailey-Hailey disease, superficial pemphigus), Darier disease, and Grover transient acantholytic dermatosis, as well as other vesiculo-bullous disorders, including bullous pemphigoid, epidermolysis bullosa, and atopic dermatitis, are prone to florid infections by herpes simplex virus (HSV)-I and -II, and, more rarely, by varicella-zoster virus (VZV). As these infections are difficult to recognize clinically and histologically, their frequency remains unknown. A possible occult viral colonization has never been documented in these disorders. The manner in which the primary bullous disorders are contaminated by herpesviridae remains unclear.

OBJECTIVE

To retrospectively assess the possible presence of HSV and VZV in a series of biopsies of acantholytic disorders and bullous pemphigoid.

METHOD

The typical alpha-herpesviridae-related cytopathic signs were searched for by conventional microscopy in skin biopsies of patients with bullous pemphigoid (n = 20), pemphigus vulgaris (n = 19), Darier disease (n = 18), chronic benign familial pemphigus (n = 3), and Grover transient acantholytic dermatosis (n = 3). Immunohistochemistry (IHC) targeted specific HSV-I, HSV-II, and VZV antigens. Polymerase chain reaction (PCR) was used for detecting HSV- and VZV-specific DNA sequences.

RESULTS

No cytopathic signs suggestive of HSV or VZV infection were detected. However, IHC revealed HSV antigens in Darier disease (1/18, HSV-I), Grover transient acantholytic dermatosis (1/3, HSV-I), pemphigus vulgaris (1/19, HSV-I), and bullous pemphigoid (2/20, HSV-I and HSV-II). In these IHC-positive cases, PCR amplified specific HSV primers in Darier disease (1/18), pemphigus vulgaris (1/19), and bullous pemphigoid (1/20). VZV antigens and nucleic acids were never identified. The HSV antigens were nearly always restricted to the upper part of the granular layer and thus differed from the usual HSV distribution during cutaneous infection. Negative and positive controls yielded consistently positive and negative results, respectively.

CONCLUSION

This report shows for the first time that clinically and histologically occult HSV colonization may occur in Darier disease, Grover transient acantholytic disease, pemphigus vulgaris, and bullous pemphigoid. Given the frequent use of immunosuppressive treatments for primary bullous disorders, greater awareness of HSV colonization and infection is recommended in these patients.

Perineal herpes simplex infection in bedridden geriatric patients

BACKGROUND

Herpes simplex virus (HSV) lesions are prone to reactivation and recurrence in response to various local or systemic triggering factors.

OBJECTIVE

To study the characteristics of five bedridden geriatric patients who presented with herpetic recurrences on the buttocks, gluteal cleft, and perianal region during hospitalization.

METHODS

Data were gathered regarding age, gender, reason for hospitalization, localization of lesions, clinical presentation, previous clinical diagnosis and topical treatments, immune status and immunosuppressant drug intake, as well as prior history of labial or genital herpes. A skin biopsy was taken for histologic examination and immunohistochemical viral identification. Viral culture and viral serology were performed and data regarding antiviral therapy were recorded.

RESULTS

The five patients (three women, two men) were aged >80 years and hospitalized for either severe drug-induced renal insufficiency (one case), severe pneumonia (two cases), or stroke causing restricted mobility (two cases). Numerous well demarcated, painful ulcerations developed in the perianal region of these patients, and one patient also presented with some vesicular lesions. The lesions had been confused with mycotic and/or bacterial infections for 10-14 days. No inguinal lymphadenopathies were present and there was no fever. None of the patients had a previous history of recurrent labial or genital HSV infections or HIV infection. Histology was suggestive of HSV infection in two of five patients. Immunohistochemistry identified HSV type I (three patients) and HSV type II (two patients) infections. Viral culture with immunofluorescence viral identification revealed HSV type I in one of the four patients in whom a swab for viral culture was taken. Serology revealed past HSV infection. All lesions cured gradually after 10-14 days of intravenous acyclovir (aciclovir) treatment.

CONCLUSION

Herpetic lesions of the perineal region represent a rare complication in bedridden geriatric patients in the absence of a previous history of HSV infections at the same site. Common traits of patients with this condition were the presence of numerous ulcerated lesions, prolonged time course, and confinement to bed. The latter probably modifies the skin condition, which triggers viral reactivation and favors cutaneous extension of the infection. Complementary diagnostic methods for viral detection and identification are mandatory.

Exclusive Involvement of Folliculosebaceous Units by Herpes

The histopathological changes of herpes simplex, herpes zoster, and varicella are considered to be indistinguishable from one another. Evaluation of the clinical setting, with adjunctive studies if necessary, generally clarifies the specific diagnosis. Vesicular lesions in all three conditions can involve epidermal and adnexal epithelium with characteristic cytopathic features. We describe three patients with non-vesicular eruptions on the head and neck whose biopsies revealed exclusive folliculosebaceous involvement by herpes. All three patients developed typical herpes zoster within days of the biopsy. There is compelling scientific evidence in the literature indicating that, in herpes zoster, the virus is transported from dorsal root or trigeminal ganglia via myelinated nerves to the skin. These terminate at the isthmus of hair follicles and primary infection of follicular and sebaceous epithelium occurs. Spread of infection to the epidermis follows. In contrast, data pertaining to recurrent herpes simplex indicates that axonal transport of the virus from sensory ganglia to the skin is directed primarily to the epidermis, via terminal non-myelinated nerve twigs. The clinical evolution of our three cases and scientific data in the literature indicate that exclusive folliculosebaceous involvement by herpes, in the setting of a non-vesicular eruption, represents early herpes zoster.

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.

The scarring mechanism of smallpox

BACKGROUND

Smallpox is notorious for leaving its survivors with disfiguring scars, but it is unclear how these scars are produced. Modern dermatopathology textbooks report that smallpox produced epidermal lesions, yet the process of scarring requires dermal involvement.

OBJECTIVES

Our goal was to uncover past theories on the mechanism of smallpox scarring.

METHODS

We conducted a comprehensive review of English-language textbooks and English-translations of textbooks in general medicine, dermatology, pathology, and dermatopathology from the past 150 years as well as relevant journal publications for the same time period.

RESULTS

We identified five different theories to explain the scarring of smallpox. The five proposals are that scarring resulted from: the extension of suppuration into the dermis; the extension of suppuration into the dermis along with inappropriate treatment and scratching; secondary bacterial ecthyma; the destruction of elastic fibers; or the destruction of sebaceous glands.

CONCLUSION

The theory that best fits clinical and histological observations is that smallpox caused scars through the destruction of sebaceous glands, first proposed by Gerrit Bras in 1952. Although this explanation is not found in any dermatopathology text, it is supported by today's leading authorities on smallpox. However, since variola virions have never actually been identified in sebaceous glands, or even in the dermis, further study of preserved tissue is warranted. Until then, the mechanism of scar formation remains speculative.

Extramammary Paget's disease with superimposed herpes simplex virus infection: immunohistochemical comparison with cases of the two respective diseases

We describe an extremely rare case of genital Paget's disease with superimposed herpes simplex virus (HSV) infection. We also describe immunohistochemical comparison of this lesion with 19 cases of genital Paget's disease and 12 cases of skin lesions caused by HSV or varicella-zoster virus. The Paget cells expressed simple epithelial keratins (CK7 and CK19) and carcinoembryonic antigen (CEA), but did not express stratified epithelial keratins (CK1, CK2e, CK10, CK5/8, CK14). Conversely, the virus-infected keratinocytes were positive for stratified epithelial keratins but negative for simple epithelial keratins and CEA. In the present case, simple epithelial keratins, stratified epithelial keratins, CEA and HSV were heterogeneously expressed in the ballooning and multinucleated giant cells. These results suggest that these cells were derived from keratinocytes and Paget cells and that the production of many multinucleated giant cells resulted from the virus-mediated cell fusion between Paget cells and neighbouring keratinocytes.

Leukocytoclastic-vasculitic neuropathy associated with chronic Epstein-Barr virus infection

We report a patient with leukocytoclastic-vasculitic neuropathy associated with chronic Epstein-Barr virus (EBV) infection. A 55-year-old man had been suffering from chronic progressive axonal polyneuropathy and skin erythema for 3 years. A skin biopsy showed capillary vasculitis with clustered leukocyte fragments. Findings of serum assays, a polymerase chain reaction for EBV-DNA, and in situ hybridization indicated chronic EBV infection. Immunosuppressive treatment resulted in the gradual lessening of his general and neurologic symptoms.

Treatment of mucocutaneous presentations of herpes simplex virus infections

Infections by herpes simplex virus (HSV) types I and II are diverse and quite frequent. After primary infection, the virus establishes a life-long latency in the sensory ganglia and recrudescences may occur at an unpredictable rate. Recurrent labial and genital herpes infections represent the majority of clinical manifestations of HSV infections. Their management is currently well established using evidence-based medicine data. Primary labial herpes is generally not treated with antivirals in otherwise healthy children, although intravenous aciclovir may be offered in severe primary infections, particularly in the immunocompromised patient. The decision whether or not to treat recurrent labial herpes should be evaluated individually and depends on the frequency and severity of relapses, the impairment of the quality of life, and the cost of therapy. Patients with mild disease may benefit from topical therapy, and those with severe and frequent recurrences may be considered for intermittent or long-term oral antiviral therapy. Primary genital herpes is treated with oral or intravenous antivirals, depending on the severity of the infection and associated symptoms. Recurrent genital herpes can be managed with episodic short courses of oral antivirals in patients whose recurrences are moderate to severe and rare, and have a clear prodrome. Patients with >5 episodes/year, severe recurrences or unrecognisable prodromes may be best managed with long-term suppressive antiviral prophylaxis. HSV is also responsible for a variety of other clinical manifestations, including herpetic whitlow, neonatal infection, disseminated and atypical cutaneous infections, traumatic herpes, eczema herpeticum, and HSV-associated erythema multiforme. HSV infection may also represent a complication following cosmetic procedures of the oro-facial region, surgical and dental interventions, sun exposure and burns. Precise treatment guidelines for these HSV infections are not firmly established.

Varicella-zoster virus proteins in skin lesions: implications for a novel role of ORF29p in chickenpox

Skin biopsy samples from varicella-zoster virus (VZV)-infected patients examined by immunohistochemistry demonstrated VZV replication in nonepithelial cell types. ORF29p, a nonstructural nuclear protein, was found in nerves of two of six patients with chickenpox. In tissue culture, ORF29p was secreted by VZV-infected fibroblasts. Extracellular ORF29p can be taken up through endocytosis by human neurons, implying a novel role for this protein in pathogenesis.

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.

Varicella-zoster virus immune evasion

CD4+ and CD8+ T cells play dual roles in varicella-zoster virus (VZV) pathogenesis. The first role is to deliver the virus to cutaneous sites during primary VZV infection, permitting replication at these sites and the successful transmission of the virus to other susceptible individuals. The second contribution of T cells is to provide the critical antigen-specific adaptive immunity needed to stop viral replication and maintain VZV latency in sensory ganglia. The equilibrium between VZV and the host can be predicted to be served by immune evasion mechanisms in at least two important ways, including the facilitation of cell-associated viremia during primary VZV infection and silent persistence in dorsal root ganglia. Interference with antigen presentation by MHC class I downregulation may be expected to play a role in both circumstances. Transient interference with MHC class II expression in varicella skin lesions should facilitate local replication and transmission. In addition, when VZV reactivates, the capacity of viral gene products to block the upregulation of MHC class II expression triggered by interferon-gamma should permit a sufficient period of viral replication to cause the lesions of herpes zoster, despite the presence of VZV-specific T cells, and to allow transmission of the virus to susceptible individuals. Although the effort is at an early stage compared to studies of other viral pathogens, identifying the VZV gene products that exert these effects and their mechanisms of interference has the potential to reveal novel aspects of MHC class I and class II antigen processing and presentation.

Chronic herpes simplex virus type I glossitis in an immunocompromised man

Herpes simplex virus (HSV) type 1 (HSV-1) infection of the tongue commonly accompanies acute primary herpetic gingivostomatitis. However, recurrent infection of the tongue is exceptional and is restricted to immunocompromised individuals. A 57-year-old man with corticosteroid-dependent chronic obstructive pulmonary disease and sciatica presented with a chronic median glossitis due to HSV-1. The main clinical and histological feature was massive necrosis of the entire mucosa. Immunohistochemistry demonstrated a considerable amount of HSV gB, gC and gD envelope glycoproteins dispersed in the chorion. In contrast, HSV-1 DNA was detected only in a limited number of epithelial cells using in situ hybridization. The extent of necrosis and the pattern of viral DNA and envelope protein distribution represent unique features of median herpetic glossitis, which are not found in more common types of HSV infection.

Macrophage protection against human immunodeficiency virus or herpes simplex virus by red blood cell-mediated delivery of a heterodinucleotide of azidothymidine and acyclovir

Human herpesvirus (HSVs) are distributed worldwide and are among the most frequent causes of viral infection in HIV-1-immunocompromised patients. Hence, therapeutic strategies able to inhibit HSV-1 and HIV-1 replication are sorely needed. Until now, the most common therapies against HSV-1 and HIV-1 infectivity have been based on the administration of nucleoside analogs; however, to be active, these antiviral drugs must be converted to their triphosphorylated derivatives by viral and/or cellular kinases. At the cellular level, the main problems involved in the use of such drugs are their limited phosphorylation in some cells (e.g., antiretroviral drugs in macrophages) and the cytotoxic side effects of nucleoside analog triphosphates. To overcome these limitations, a new heterodinucleotide (AZTp2ACV) consisting of both an antiretroviral and an antiherpetic drug, bound by a pyrophosphate bridge, was designed and synthesized. The impermeant AZTp2ACV was encapsulated into autologous erythrocytes modified to increase their recognition and phagocytosis by human macrophages. Once inside macrophages, metabolic activation of the drug occurred. The addition of AZTp2ACV-loaded erythrocytes to human macrophages provided effective and almost complete in vitro protection from HIV-1 and HSV-1 replications, respectively. Therefore, AZTp2ACV acts as an efficient antiviral prodrug following selective targeting to macrophages by means of loaded erythrocytes.

In situ hybridization detection of varicella zoster virus in paraffin-embedded skin biopsy samples

BACKGROUND

When virologic and molecular diagnostic techniques are unavailable, the diagnosis of varicella zoster virus (VZV) infection depends on clinical criteria and histologic evaluation of skin biopsy specimens or Tzank preparations. These methods can misdiagnose chickenpox and zoster, particularly when the clinical manifestations are atypical.

OBJECTIVE

To improve diagnosis in these settings, we developed an in situ hybridization technique for the detection of VZV utilizing a fluorescein-labeled oligonucleotide probe visualized with anti-fluorescein alkaline phosphatase-conjugated antibody.

STUDY DESIGN

We retrospectively examined 26 paraffin-embedded skin biopsy specimens with histologic features consistent with VZV or herpes simplex virus (HSV) infection and 11 control cases by in situ hybridization. In situ hybridization for VZV and HSV-1 was compared with polymerase chain reaction (PCR) for VZV and HSV-1 and clinical and histologic examination.

RESULTS

Thirteen of the 26 study cases and two of the 11 control cases were positive for VZV by in situ hybridization. When compared with PCR, in situ hybridization was 92% sensitive and 88% specific. When compared with clinical diagnosis, in situ hybridization was 86% sensitive and 87% specific. All cases of chickenpox had VZV-positive inflammatory cells in the dermis but this finding was less frequent among the cases of zoster.

CONCLUSIONS

This in situ hybridization technique is a sensitive and specific method for the diagnosis of VZV in skin lesions that is applicable to most histopathology laboratory settings. In addition, in situ hybridization reveals individual infected cells and may provide insight into the pathogenesis of VZV skin infection.

Hair follicle involvement in herpes zoster: pathway of viral spread from ganglia to skin

Herpes zoster is caused by reactivation of varicella-zoster virus (VZV) persisting in dorsal root or trigeminal ganglia. To clarify the pathway of viral spread from the ganglia to skin, 16 biopsy specimens of early skin lesions of herpes zoster obtained from the face and trunk of 13 patients were studied histologically and immunohistochemically using monoclonal antibodies to the structural proteins of VZV. VZV-infected cells were detected in the hair follicles in 10 of the 16 specimens and in the epidermis in 2 specimens. Infected cells were localized in the isthmus of every involved follicle (12/12), frequently in the stem (8/10) and infundibulum (6/10), and never in the bulb. The high frequency of follicular involvement in herpes zoster suggests that VZV spreads to the area of skin innervated by myelinated nerves, which end around the isthmus of hair follicles and sebaceous glands.

Distribution of varicella zoster virus and herpes simplex virus in disseminated fatal infections

AIMS

To study the cutaneous and visceral distribution of herpes simplex virus (HSV) and varicella zoster virus (VZV) in fatal infections.

METHODS

Standard histology, immunohistochemistry (monoclonal antibodies VL8 and VL2 and polyclonal antibody IE63 directed against VZV; monoclonal antibodies IBD4 and HH2 and polyclonal antibodies directed against HSVI and HSVII) and in situ hybridisation (anti-HSV and anti-VZV probes) were applied to formalin fixed, paraffin wax sections.

RESULTS

On histological examination, Herpesviridae infection was evident in various organs including the lungs, liver and skin. In addition, immunohistochemistry and in situ hybridisation revealed the presence of HSV and VZV antigens and nucleic acids in several cell types and tissues showing no cytopathological alterations suggestive of Herpesviridae infection. The organs with histological evidence of infection also contained VZV or HSV antigens and their genes.

CONCLUSIONS

These findings suggest that organ failure in disseminated VZV and HSV infections is primarily caused by HSV or VZV induced cell damage and lysis. They also indicate that immunohistochemistry and in situ hybridisation can provide an accurate, type-specific diagnosis on formalin fixed, paraffin wax embedded tissue even when classic histological and cytological characteristics are lacking.

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

Early and specific recognition of varicella zoster virus (VZV) infection is of vital concern in immunocompromised patients. The aim of this study was to compare the diagnostic accuracy of histochemical and immunohistochemical identification of the VZV ORF63 encoded protein (IE63) and of the VZV late protein gE on smears and formalin-fixed paraffin-embedded skin sections taken from lesions clinically diagnosed as varicella (n = 15) and herpes zoster (n = 51). Microscopic examinations of Tzanck smears and skin sections yielded a diagnostic accuracy of Herpesviridae infections in 66.7% (10/15) and 92.3% (12/13) of varicella, and 74.4% (29/39) and 87.8% (43/49) of herpes zoster, respectively. Immunohistochemistry applied to varicella provided a type-specific virus diagnostic accuracy of 86.7% (13/15; IE63) and 100% (15/15; gE) on smears, and of 92.3% for both VZV proteins on skin sections. In herpes zoster, the diagnostic accuracy of immunohistochemistry reached 92.3% (36/39; IE63) and 94.9% (37/39; gE) on smears, and 91.7% (44/48; IE63) and 91.8% (45/49; gE) on skin sections. These findings indicate that the immunohistochemical detection of IE63 and gE on both smears and skin sections yields a higher specificity and sensitivity than standard microscopic assessments.

Distribution of varicella-zoster virus gpI and gpII and corresponding genome sequences in the skin

In the course of varicella-zoster virus (VZV) infection, some viral capsid antigens are found in the epidermis and dermis. The aim of this study was to investigate the localisation of two major VZV glycoproteins (gpI and gpII) and of their respective genes in the skin. The distribution of VZV gpI and II in 27 formalin fixed paraffin embedded skin biopsies from herpes zoster eruptions were compared by immunohistochemistry. Double immunostaining was carried our to identify infected cells. The presence of viral nucleic acids coding for gpI and gpII was examined by in situ hybridisation. The distribution of gpI and gpII and their corresponding genome sequences was similar in the epidermis. gpI and gpII were also detected in dermal FXIIIa positive dendrocytes, in Mac 387 and CD68 positive macrophages, and in perineural and endothelial cells. However, the corresponding viral nucleic acids were rarely and barely detected in these cells of the dermis. It is concluded that VZV infection of epithelial cells follows a different course than in dermal cells.

Varicella-zoster virus gene 63 encodes an immediate-early protein that is abundantly expressed during latency

Varicella-zoster virus (VZV) gene 63 encodes a protein with a predicted molecular mass of 30.5 kDa which has amino acid similarities with the immediate-early (IE) protein 22 (ICP-22) of herpes simplex virus type 1. In order to study the expression of this protein during lytic and latent infection, gene 63 was cloned in frame and downstream from the glutathione-S-transferase gene, expressed as a fusion protein, and purified. In VZV-infected Vero cells, antibodies directed against this protein detect two polypeptides of 45 and 38 kDa which are localized both in the cytoplasm and in the nucleus. Using a sequential combination of transcription and protein synthesis inhibitors (actinomycin D and cycloheximide, respectively), we demonstrated the immediate-early nature of this protein, which can thus be named IE63. Using a rat model of VZV latency, we showed that IE63 is heavily expressed, essentially in neurons, during latency. IE63 can also be detected in the skin of patients showing early herpes zoster symptoms.

Branch retinal artery occlusion (BRAO) combined with branch retinal vein occlusion (BRVO) and optic disc neovascularization associated with HIV and CMV retinitis

Two vaso-occlusive events, branch retinal artery occlusion (BRAO) and branch retinal vein occlusion (BRVO), were observed in the retina of an HIV-infected patient with cytomegalovirus (CMV) retinitis who developed neovascularization of the disc (NVD). Although BRVO and reversible NVD have been reported in association with CMV retinitis, we have seen no reports of concomitant BRAO. CMV damages endothelial cells and causes an occlusive vasculitis. In HIV-infected individuals, damaged endothelial cells and rheologic problems result in increased blood viscosity. HIV infection has also been associated systemically with elevated levels of cytokines, including tumor necrosis factor alpha (TNF-alpha). In vitro, TNF-alpha exerts effects that decrease fibrinolytic potential; this activity in the circulation of a patient with AIDS may lead to vascular occlusive events. In the patient reported here, the retinal changes were not reversed by induction therapy with ganciclovir and the NVD did not regress.

Recognition and treatment of shingles

Varicella zoster virus (VZV) is responsible for a primary infection (varicella) followed by a latency, eventually resulting in herpes zoster (shingles). The replication cycle of VZV is normally interrupted after varicella. Consequently, VZV remains dormant in the organism. Reactivation occurs after viraemia, and the development of tissue alterations (skin and viscera) depends on the immunological status of the patient. Diagnosis of herpes zoster relies on clinical recognition and cytological and histological evaluations combined with immunohistochemistry and molecular biology techniques. Treatment of herpes zoster primarily relies upon antiviral drugs and incidentally on immunomodulating agents, specific immunoglobulins, antimicrobial agents, antiviral enzymes and corticosteroids. Drugs with a clinically relevant activity against varicella zoster virus infections include aciclovir, adenosine monophosphate, bromodeoxyuridine, desciclovir, fiacitabine, idoxuridine, interferon-alpha and vidarabine. Among them, aciclovir appears to be a first-line agent. Its efficacy has been well established by many clinical studies. Promising drugs for the future include famciclovir, penciclovir, valaciclovir and other molecules currently under investigation. Recent and promising improvements in antiviral drug development may increase patient compliance, cost-benefit ratios and therapeutic efficacy.