[Contribution of GIGA I3 (GIGA-Infection, Immunity and Inflammation) to the understanding of the complex pathogen-host-environment interplay]. / Apport du GIGA I3 (GIGA-Infection, Immunité et Inflammation) à la compréhension des interactions complexes entre l'individu et son environnement.

COVID-19 has highlighted the necessary synergy between clinicians and researchers. Such synergy constitutes the DNA of GIGA I3 (GIGA-Infection, Immunity and Inflammation) and makes its wealth. It ensures the translational nature of the research projects on pathologies involving the immune system in an infectious or non-infectious context.

: La COVID-19 a mis en lumière la nécessaire synergie entre cliniciens et chercheurs dits fondamentalistes. Une telle synergie constitue l'ADN de GIGA I3 (GIGA-Infection, Immunité et Inflammation) et en fait sa richesse. Elle permet d'assurer le caractère translationnel des recherches menées sur des pathologies impliquant le système immunitaire dans un contexte infectieux ou non.

Herpes simplex virus type-I and pyogenic granuloma: a vascular endothelial growth factor-mediated association?

Pyogenic granuloma (PG) is a vascular endothelial growth factor (VEGF)-related neoangiogenic process. Minor trauma, chronic irritation, certain drugs and pregnancy may favor PG. Viral triggers have not been reported up to date. A 52-year-old woman with hairy-cell leukemia presented because of a 3-month history of a giant pseudotumoral lesion on her left cheek. All prior antibacterial, antifungal and anti-inflammatory treatments had failed. Histology revealed PG with sparse and isolated epithelial cell aggregates. Immunohistochemistry (IHC) identified herpes simplex virus type-I (HSV-I) antigens in the nuclei and cytoplasm of normal-appearing as well as cytopathic epithelial cells, suggesting a chronic, low-productive HSV infection. No HSV-I signal was evidenced in the endothelial cells of the PG. Furthermore, IHC revealed VEGF in the HSV-I infected epithelial cells as well as within the PG endothelial cells. These results incited oral treatment with valaciclovir, and the PG promptly resolved after 2 weeks. These findings suggest that a chronic HSV-I infection might play an indirect, partial role in neoangiogenesis, presumably via HSV-I infection-related stimulation of keratinocytic VEGF production.

[Varicelle zoster virus, an alphaherpesvirus different from others]. / Le virus de la varicelle et du zona : un alphaherpesvirus pas vraiment comme les autres...

Varicella Zoster virus (VZV) is an alphaherpesvirus responsible for two well-known pathologies. It is indeed the etiological agent of varicella (chickenpox), a childhood infection and zoster (shingles) which results from the reactivation of the virus remained latent in sensory ganglia. Only eight of the 120 Herpesviruses described so far, among which VZV and Herpes Simplex type-1 and type 2 (HSV-1, -2), are able to infect humans. For many years, HSV-1, which has been extensively studied has been considered as the prototype of this family. Nevertheless, data accumulated over the last 15 years tend to demonstrate that VZV is quite different from its cousin, particularly concerning the mechanisms that control latency. Epidemiological data confirm the differences between these two viruses : in our temperate countries, VZV infects very young children and zoster, usually observed only once is more frequent in the elderly. On the contrary, primary infections due to HSV-1 happen later and reactivations episodes are numerous and decrease with age. A better understanding of the VZV biology has allowed to develop efficacious antiviral compounds and to produce a vaccine whose efficacy has been demonstrated in the United States where a universal varicella vaccination program has started 10 years ago.

Varicella-Zoster virus gene expression in latently infected rat dorsal root ganglia.

Latent infection of human ganglia with Varicella-Zoster virus (VZV) is characterized by a highly restricted pattern of viral gene expression. To enhance understanding of this process we used in situ hybridization (ISH) in a rat model of VZV latency to examine expression of RNA corresponding to eight different VZV genes in rat dorsal root ganglia (DRG) at various times after footpad inoculation with wild-type VZV. PCR in situ amplification was also used to determine the cell specificity of latent VZV DNA. It was found that the pattern of viral gene expression at 1 week after infection was different from that observed at the later times of 1 and 18 months after infection. Whereas multiple genes were expressed at 1 week after infection, gene expression was restricted at the later time points when latency had been established. At the later time points after infection the RNA transcripts expressed most frequently were those for VZV genes 21, 62, and 63. Gene 63 was expressed more than any other gene studied. While VZV DNA was detected almost exclusively in 5-10% of neurons, VZV RNA was detected in both neurons and nonneuronal cells at an approximate ratio of 3:1. A newly described monoclonal antibody to VZV gene 63-encoded protein was used to detect this protein in neuronal nuclei and cytoplasm in almost half of the DRG studied. These results demonstrate that (1) this rat model of latency has close similarities in terms of viral gene expression to human VZV latency which makes it a useful tool for studying this process and its experimental modulation and (2) expression of VZV gene 63 appears to be the single most consistent feature of VZV latency.

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.

Varicella-zoster virus IE63, a virion component expressed during latency and acute infection, elicits humoral and cellular immunity.

Varicella-zoster virus (VZV) latency in human dorsal root ganglia is characterized by the transcription of large regions of its genome and by the expression of large amounts of some polypeptides, which are also expressed during lytic cycles. The immediate early 63 protein (IE63) is a virion component expressed very early in cutaneous lesions and the first viral protein detected during latency. Immune response against IE63 has been evaluated among naturally immune adults with a history of chickenpox: Specific antibodies were detected in serum, and most subjects who had a T cell proliferation with unfractionated VZV antigens had T cell recognition of purified IE63. The cytotoxic T cell (CTL) response to IE63 was equivalent to CTL recognition of IE62, the major tegument component of VZV, whose immunogenicity has been previously described. T cell recognition of IE63 and other VZV proteins is one of the likely mechanisms involved in controlling VZV reactivation from latency.

Low-productive alpha-herpesviridae infection in chronic lichenoid dermatoses.

BACKGROUND: Herpes simplex virus (HSV) and Varicella-zoster virus (VZV) are responsible for various atypical mucocutaneous manifestations in the immunosuppressed population. One of the causative pathomechanisms suggests an altered virus-host cell relationship. OBJECTIVE/METHODS: This report investigates by histology, immunohistochemistry and in situ hybridization the histological and virological features of 6 protracted, indolent HSV infections and 2 prolonged zoster infections. RESULTS: Histopathology revealed a lichenoid dermatitis in all patients. Specific HSV-1, HSV-2 and VZV in situ hybridization proved the viral origin of the cutaneous lesions. Immunohistochemical assessment demonstrated the intracellular presence of the HSV glycoproteins gB, gC and gD in epidermal keratinocytes which did not exhibit cytolysis. Similar findings were obtained for the VZV gE and gB. CONCLUSION: These results suggest that in some instances HSV and VZV infections may present a protracted disease course associated with a lichenoid inflammatory pattern and a non-cytolytic virus-host cell relationship.

Recognition of the latency-associated immediate early protein IE63 of varicella-zoster virus by human memory T lymphocytes.

Varicella-zoster virus (VZV) is a human alpha herpesvirus that establishes latency in sensory ganglia. Latency is characterized by the abundant expression of the immediate early protein 63 (IE63), whereas other viral proteins have not yet been detected during the quiescent phase of VZV infection. The IE63 protein is a component of the virion and is expressed very early in the infectious cycle. The IE63 protein is also expressed in skin during episodes of varicella and herpes zoster. We have evaluated the cell-mediated immune response against IE63 in naturally immune adults with a history of chickenpox, by T lymphoproliferation and cytotoxicity assays. Among donors who had T cell proliferation to unfractionated VZV Ags from infected cell extract, 59% had T cell recognition of purified IE63. The CTL response to IE63 was equivalent to CTL recognition of IE62, the major tegument component of VZV whose immunogenicity has been previously described. IgG Abs against IE63 were detected in serum from healthy immune adults. These results indicate that IE63 is an important target of immunity to VZV. T cell recognition of IE63 is likely to be involved in controlling VZV reactivation from latency.

Lessons to be learned from varicella-zoster virus.

Varicella-zoster virus (VZV) is an alphaherpesvirus responsible for two human diseases: chicken pox and shingles. The virus has a respiratory port of entry. After two successive viremias, it reaches the skin where it causes typical lesions. There, it penetrates the peripheral nervous system and it remains latent in dorsal root ganglia. It is still debatable whether VZV persists in neurons or in satellite cells. During latency, VZV expresses a limited set of transcripts of its immediate early (IE) and early (E) genes but no protein has been detected. Mechanisms of reactivation from ganglia have not been identified. However, dysfunction of the cellular immune system appears to be involved in this process. The cell-associated nature of VZV has made it difficult to identify a temporal order of gene expression, but there appears to be a cascade mechanism as for HSV-1. The lack of high titre cell-free virions or recombination mutants has hindered so far the understanding of VZV gene functions. Five genes, ORFs 4, 10, 61, 62, and 63 that encode regulatory proteins could be involved in VZV latency. ORF4p activates gene promoters with basal activities. ORF10p seems to activate the ORF 62 promoter. ORF61p has trans-activating and trans-repressing activities. The major IE protein ORF62p, a virion component, has DNA-binding and regulatory functions, transactivates many VZV promoters and even regulates its own expression. ORF63p is a nuclear IE protein of yet unclear regulatory functions, abundantly expressed very early in infection. We have established an animal model of VZV latency in the rat nervous system, enabling us to study the expression of viral mRNA and protein expression during latency, and yielding results similar to those found in humans. This model is beginning to shed light on the molecular events in VZV persistent infection and on the regulatory mechanisms that maintain the virus in a latent stage in nerve cells.

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.

Varicella-zoster virus latency in the adult rat is a useful model for human latent infection.

A model of latent infection by varicella-zoster virus (VZV) was obtained in the adult rat. Inoculation of VZV-infected cells in the skin led to infection of the peripheral nervous system. Latency was characterized by a long-lasting presence of the viral genome, of selected viral gene transcripts, and of at least one viral protein in the dorsal root ganglia. Reactivation has not been obtained in vivo, but has occurred ex vivo after repeated stresses. Many similarities with VZV latency in humans were found, making this model useful for vaccine and antiviral studies.

Localization of varicella-zoster virus nucleic acids and proteins in human skin.

The pathogenic mechanisms involved in varicella-zoster virus (VZV) infections remain elusive. The pattern of cutaneous distribution of the IE63 protein and of the gpI (gE) and gpII glycoproteins with their corresponding genome sequences during VZV infections was studied by immunohistochemistry and in situ hybridization. Skin biopsy specimens were obtained from immunocompetent and immunocompromised patients with varicella, herpes zoster, or atypical VZV lesions. The first evidence for VZV infection consisted of the presence of IE63 in keratinocytes. In the vesicles and pustules, the viral transcripts gpI, gpII, and IE63 and the corresponding nucleic acids for gpI and gpII were identified in keratinocytes, sebocytes, Langerhans cells, dermal dendrocytes, monocytes/macrophages, and endothelial cells. The gpI and gpII glycorpoteins were essentially located on the cellular membranes while IE63 expression was generally restricted to the nuclei. In three biopsies of early herpes zoster, viral proteins were disclosed in dermal nerves and in perineurial type I dendrocytes. This was never encountered in varicella. Vasculitic changes and endothelial cell involvement were more prominent in varicella than in herpes zoster. It is concluded that the secondary viremia in varicella that affects the dermal endothelial cells is followed by a cell-to-cell spread to keratinocytes. In herpes zoster, the viral progression through cutaneous nerves primarily extends to the pilosebaceous units with a secondary involvement of epidermal keratinocytes, followed by a further spread to dermal cells.

Varicella-zoster virus induces apoptosis in cell culture.

Apoptosis is an active mechanism of cell death which can be initiated in response to various stimuli including virus infections. In this work, we demonstrate that lytic infection by varicella-zoster virus (VZV), a human herpesvirus, is characterized by nuclear fragmentation of DNA into oligonucleosomal fragments and by chromatin condensation. In vitro, VZV-induced cell death is actually mediated by apoptosis. The mechanisms developed by cells to protect themselves against apoptosis could be one of the parameters allowing the establishment of virus latency. In the case of VZV, which can remain latent in sensory ganglia, we have not yet identified a cellular or viral protein which could play this protective role, since the observed apoptosis mechanism seems to be independent from Bcl-2, the most frequently described inhibitor of apoptosis.

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.

Viral glycoproteins in herpesviridae granulomas.

Granulomatous reactions after varicella zoster virus (VZV) and herpes simplex virus (HSV) infections are rare, and their pathogenesis remains unclear. We studied by immunohistochemistry and in situ hybridization early granulomatous reactions after VZV and HSV infections. In the five cases studied, the VZV glycoproteins gp I and gp II were present in cells abutted to altered vessels, but the corresponding genome sequences were disclosed in similar locations in only one of these cases. In an immunocompromised patient with diffuse HSV eruption, HSV I antigens were present in cells of the reticular dermis, while viral nucleic acids were not evident. Immunophenotyping of the granulomas showed strong Mac 387 and CD68 positive labelings of macrophages/monocytes, without any involvement of Factor XIIIa-positive cells. These findings suggest that the major viral envelope glycoproteins, rather than complete viral particles could trigger granuloma formation following HSV and VZV skin infections.

Successful treatment of progressive mucocutaneous infection due to acyclovir- and foscarnet-resistant herpes simplex virus with (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (HPMPC).

The acyclic nucleoside phosphonate (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (HPMPC) was used topically for the treatment of persistent mucocutaneous infections in two cases. One patient with AIDS suffered from a perineal lesion due to infection with herpes simplex virus type 2 (HSV-2) and did not respond to acyclovir and was intolerant of foscarnet. A bone marrow transplant recipient developed orofacial lesions due to infection with herpes simplex virus type 1 (HSV-1) that failed to respond to therapy with both acyclovir and foscarnet. After topical application of HPMPC, the HSV-2 lesions completely resolved. However, the lesions recurred 3 weeks later, and, upon subsequent treatment with HPMPC, regressed. On recurrence, the virus was found to be sensitive to acyclovir, which the patient was given. Again HSV-2, which was resistant to acyclovir, emerged; similar observations were made after another cycle of HPMPC therapy. The HSV-1 isolates were resistant to acyclovir and foscarnet. Following local HPMPC treatment, the lesions regressed, but after 1 week, a second course of topical HPMPC therapy had to be instituted for recurrent infection. The lesions again regressed, and as the recurrent virus was sensitive to acyclovir, the patient was successfully treated with the drug. The results of this study point to the potential usefulness of topical HPMPC in the treatment of immunocompromised patients with HSV-related mucocutaneous infections that are refractory to therapy with acyclovir and/or foscarnet.

Meningoradiculoneuritis due to acyclovir-resistant varicella zoster virus in an acquired immune deficiency syndrome patient.

Varicella zoster virus (VZV) is recognized as one of the major viral pathogens reactivated in patients with the acquired immune deficiency syndrome (AIDS). We report the case of meningoradiculoneuritis in an AIDS patient,associated with the isolation in the cerebrospinal fluid (CSF) of a thymidine kinase (TK)-deficient, acyclovir (ACV)-resistant strain of VZV. Although the virus was sensitive in vitro to phosphonoformate (PFA), the patient did not improve during PFA therapy and finally died. Several VZV strains isolated from this patient (including two isolates from the patient's CSF) were analyzed for their TK activity and subsequently the viral TK gene was sequenced showing a major deletion leading to a truncated protein. Their susceptibility to several antiviral agents including ACV, PFA, (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU), 9-beta-D-arabinofuranosyladenine (vidarabine), (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl) cytosine (HPMPC), and (S)-9-(3-hydroxy-2-phosphonyl-methoxypropyl)adenine (HPMPA) was evaluated. All the virus strains isolated from this patient remained sensitive to HPMPA and HPMPC, pointing to the potential usefulness of these acyclic nucleoside phosphonates for the treatment of ACV-resistant VZV infections in immunocompromised patients.