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.     

Scanning and transmission electron microscopic studies of lesional epidermis in herpes zoster

The epidermal skin lesions of herpes zoster were studied by scanning (SEM) and transmission electron microscopy (TEM). When erythematous lesions were observed by TEM, many of the infected keratinocytes showed evidence of cell degeneration, being characterized by swollen nuclei, disappearance of desmosomes, and widening of intercellular spaces. Macrophages and/or lymphocytes migrated through the intercellular spaces between degenerated keratinocytes. In the vesicular lesions, SEM and TEM showed some infiltrating neutrophils, directly adhering to the virus-infected keratinocytes, with swollen nuclei and irregularly clumped chromatin. In some specimens, balloon-degenerated keratinocytes were observed in the cavity. In the pustular stage, ruptured keratinocytes and numerous neutrophils were observed in the reticular-degenerated epidermal tissue. These results suggest that, in herpes zoster, the epidermal damage may be due, at least in part, to cell-mediated host immunity as well as to the cytopathic effect of varicella-zoster virus.     

Varicella zoster virus vaccine--a review

The available published data on the efficacy and safety of a live attenuated varicella vaccine is presented. The data indicate that immunosuppressed leukemic children at high risk for severe varicella can be vaccinated resulting in complete or partial immunity in most children. Vaccination of immunosuppressed children is often associated with fever and rash. There seems to be a decreased risk of herpes zoster in vaccinated leukemic children when compared with a group of naturally infected leukemic children. In order to diminish the risk of varicella zoster virus (VZV) transmission to these high-risk persons family members of these, if susceptible to varicella infection, should be immunized. Although vaccination of healthy children is highly effective and associated with a low frequency of adverse events, vaccination in this group may be questioned due to the benign course of varicella. Due to the more severe VZV-infection seen among non-immune healthy adults, it seems reasonable to offer vaccination to this group. It will, however, require extensive serological testing to identify seronegative individuals. From a theoretical point of view a booster-vaccination to the elderly population, resulting in detectable cell-mediated immunity to VZV, should reduce the risk of herpes zoster. Large placebo-controlled studies are needed to confirm if such an immunization can prevent herpes zoster in this age group.     

Mutational analysis of the role of glycoprotein I in varicella-zoster virus replication and its effects on glycoprotein E conformation and trafficking

The contributions of the glycoproteins gI (ORF67) and gE (ORF68) to varicella-zoster virus (VZV) replication were investigated in deletion mutants made by using cosmids with VZV DNA derived from the Oka strain. Deletion of both gI and gE prevented virus replication. Complete deletion of gI or deletions of 60% of the N terminus or 40% of the C terminus of gI resulted in a small plaque phenotype as well as reduced yields of infectious virus. Melanoma cells infected with gI deletion mutants formed abnormal polykaryocytes with a disrupted organization of nuclei. In the absence of intact gI, gE became localized in patches on the cell membrane, as demonstrated by confocal microscopy. A truncated N-terminal form of gI was transported to the cell surface, but its expression did not restore plaque morphology or infectivity. The fusogenic function of gH did not compensate for gI deletion or the associated disruption of the gE-gI complex. These experiments demonstrated that gI was dispensable for VZV replication in vitro, whereas gE appeared to be required. Although VZV gI was dispensable, its deletion or mutation resulted in a significant decrease in infectious virus yields, disrupted syncytium formation, and altered the conformation and distribution of gE in infected cells. Normal cell-to-cell spread and replication kinetics were restored when gI was expressed from a nonnative locus in the VZV genome. The expression of intact gI, the ORF67 gene product, is required for efficient membrane fusion during VZV replication.     

Cerebral infarction associated with vasculitis due to varicella zoster virus in patients infected with the human immunodeficiency virus

Cases of herpes zoster ophtalmicus (HZO) with delayed contralateral hemiparesis caused by hemispheric stroke secondary to granulomatous angiitis have been reported and are a well-recognized complication of herpes zoster. Similar cases have been reported more recently during infection with human immunodeficiency virus (HIV). We describe two HIV+ patients without any clinical history of zoster dermatitis who developed a sudden hemiparesis followed 2 weeks later for one by an acute retinal necrosis. Computerized tomography (CT) scan, magnetic resonance imaging (MRI), magnetic resonance angiography (MRA), and digital subtraction angiography (DSA) were performed and showed a hemispheric stroke with evidence of a segmental arteritis of the carotid syphon. Varicella zoster virus (VZV) was found in the cerebro spinal fluid (CSF) in the two patients and after puncture of the vitreous fluid of the patient with the acute retinal necrosis. These two cases exemplify the difficulty of diagnosis of stroke in HIV+ patients, which seems to be more frequent than in similarly aged non-infected patients and demonstrates that VZV needs to be taken in consideration and identified even without any past history of zoster dermatitis.     

Subcutaneous implantation metastasis of a cholangiocarcinoma of the bile duct after percutaneous transhepatic biliary drainage (PTBD)

The differential diagnosis of herpes simplex and zoster may require virological confirmation, yet virus typing is not regarded as necessary in routine dermatological assessment. In an attempt to evaluate the clinical benefits of the routine detection of herpes simplex virus (HSV) and varicella zoster virus (VZV), we analysed skin swabs from 110 patients who were diagnosed at the first clinical visit as having herpes simplex (n = 45) or zoster (n = 65). Viruses were typed using the polymerase chain reaction (PCR) with the general primer pair GPHV-RU. PCR analysis showed that at the initial clinical presentation, herpes simplex in these patients was not mistaken for zoster but that zoster was incorrectly diagnosed as herpes simplex in nine cases. Thus these results suggest that initial zoster often mimics herpes simplex, hence routine PCR diagnosis of HSV and VZV or alternative rapid diagnostic approaches may be beneficial in these cases.     

Infrequent detection of cytomegalovirus and Epstein-Barr virus DNA in synovial membrane of patients with rheumatoid arthritis

OBJECTIVE: To study the role of the cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus types 1 and 2 (HSV-1 and 2), varicella zoster virus (VZV), and human herpes virus 6 (HHV-6) in the etiology of rheumatoid arthritis (RA). METHODS: Polymerase chain reaction (PCR) was used to detect DNA of the different herpes viruses in synovial membranes from 31 patients with chronic RA and 14 control patients. Specific antibodies were determined by indirect immunofluorescence and ELISA. RESULTS: Out of 31 patients with RA, CMV DNA was detected in synovial membranes from 2 patients and EBV DNA was detected in synovial membranes from 2 other patients. All samples from the patients with RA were negative for DNA from HSV-1 and 2, VZV, and HHV-6. All samples from the 14 control patients were negative in all PCR assays. No statistically significant differences in IgG antibodies were found for CMV, HSV-1, VZV, and HHV-6 in patients with RA compared to controls. Higher titers of IgG antibodies against EBV viral capsid antigen were found in patients with RA, with a significance of p < 0.05. CONCLUSION: Both CMV and EBV DNA were detected in synovial membranes from 6% of the patients with RA. We cannot exclude the possibility that these viruses were associated with disease development in a minority of patients with RA.     

The inverted repeat regions of the simian varicella virus and varicella-zoster virus genomes have a similar genetic organization

Simian varicella virus (SVV) causes a varicella-like disease in nonhuman primates. The DNA sequence and genetic organization of the inverted repeat region (RS) of the SVV genome was determined. The SVV RS is 7559 bp in size with 56% guanine+cytosine (G+C) content and includes 3 open reading frames (ORFs). The SVV RS1 ORF encodes a 1279 amino acid (aa) protein with 58 and 39% identity to the varicella-zoster virus (VZV) gene 62 and herpes simplex virus type 1 (HSV-1) ICP4 homologs, respectively. The predicted 261 aa SVV RS2 polypeptide possesses 52% identity with the VZV gene 63 homolog and 23% identity with the HSV-1 ICP22. The SVV RS3 encodes a 187 aa polypeptide with 56% and 28% identity to the VZV gene 64 and the HSV-1 US10 homologs, respectively, and includes an atypical zinc finger motif. A G+C-rich 16 base-pair (bp) sequence which is repeated 7 times and a putative SVV origin of replication were identified between the RS1 and RS2 ORFs. Comparison with the VZV RS indicates the SVV and VZV RS regions are similar in size and genetic organization.     

The prophylactic effect of immunization with DNA encoding herpes simplex virus glycoproteins on HSV-induced disease in guinea pigs

Plasmid expression vectors encoding herpes simplex virus type 2 (HSV-2) glycoproteins B (gB) or D (gD) were constructed and tested for their ability to immunize guinea pigs against genital HSV infection. Immunization with a plasmid expressing the aminoterminal 707 amino acids (aa) of gB induced humoral immune responses detected by ELISA and virus neutralization. When challenged by vaginal infection, immunized animals were partially protected from genital herpes, exhibiting significantly reduced primary and subsequent recurrent disease. When the gB plasmid was combined with a plasmid expressing full-length gD, immunized guinea pigs developed humoral responses to both proteins and were also significantly protected from viral challenge.     

Postherpetic neuralgia in immunocompetent elderly people

The most menacing complication of herpes zoster in immunocompetent elderly people is chronic pain or postherpetic neuralgia (PHN). The cardinal epidemiological feature of PHN is its striking relationship to aging. Among zoster patients over 60 years old, estimates of the occurrence of PHN, defined as pain 1 month after rash onset, vary from 27 to 68%. The pathogenesis of PHN is incompletely understood but seems to involve varicella-zoster virus (VZV)-induced damage of peripheral afferent neurons and resultant changes in central afferent neurons and efferent pain-modulating neurons. PHN improves over time in many elderly patients, but an unfortunate subset experience of debilitating pain lasts for years. They experience constant and/or intermittent spontaneous pain and stimulus-evoked pain such as allodynia or hyperpathia. The outcomes of this pain include fatigue, sleep disturbance, anorexia, depression, social withdrawal, impaired activities of daily living and profound lowering of quality of life. The management of PHN is hampered by two problems: (1) a uniformly effective treatment for PHN is not available (although tricyclic antidepressants, local or regional anaesthetics, capsaicin, opiates, anticonvulsants and physical therapies are sometimes useful); and (2) early antiviral therapy of zoster may be ineffective in preventing PHN, partly related to the fact that days of VZV replication and neuronal destruction have occurred by the time the patient reaches the doctor. A potential solution to the problem of PHN is the vaccination of elderly persons with the varicella vaccine to prevent or attenuate zoster or PHN.     

Synthesis of adenine derivatives and their activities against herpes virus in vitro

A series of 9-(N4-substituted acetaldehyde thiosemicarbazone) adenines were synthesized and evaluated for antiherpes virus activity. Compounds 4a-l were prepared by condensation of 9-(acetaldehyde) adenine(6) and the corresponding N4-substituted thiosemicarbazides (10). The antiviral effects of all compounds 4a-l were tested in vitro in primary rabbit kidney cell cultures infected with herpes simplex virus type 1 (HSV-1) and varicella-herpes zoster virus (VZV), and in primary human embryo cell cultures infected with herpes simplex virus type 2 (HSV-2). The results showed that the minimum inhibitory concentrations (MIC) of 4e and 4f for HSV-1 and VZV were 20, 40, 20 and 20 micrograms.ml-1, respectively, and other compounds were 200 micrograms.ml-1. For HSV-2, the MIC of all tested compounds were 300 micrograms.ml-1. We also evaluated the antiherpetic effect of 4e (and 4f) by combination with acyclovir (ACV) in the ratio of 1:1 in vitro. The MIC of the combined compounds were 2 micrograms.ml-1 for 4e and 6 micrograms.ml-1 for 4f, while their minimum cytotoxicities (MCC) in the cell were markedly reduced compared with the individual compounds.     

Comparison of primary sensitization of naive human T cells to varicella-zoster virus peptides by dendritic cells in vitro with responses elicited in vivo by varicella vaccination

Dendritic cells (DC) are potent APC during primary and secondary immune responses. The first objective of this study was to determine whether human DC mediate in vitro sensitization of naive CD4+ T cells to epitopes of the immediate early 62 (IE62) protein of varicella zoster virus (VZV). The induction of CD4+ T cell proliferative responses to eight synthetic peptides representing amino acid sequences of the VZV IE62 protein was assessed using T cells and DC from VZV-susceptible donors. The second objective was to compare in vitro responses of naive T cells with responses to VZV peptides induced in vivo after immunization with varicella vaccine. T cell proliferation was induced by three peptides, P1, P4, and P7, in 71-100% of the donors tested before and after vaccination using DC as APC. Monocytes were effective APC for VZV peptides only after immunization. Two peptides, P2 and P8, induced naive T cell proliferation less effectively and were also less immunogenic for T cells from vaccinated or naturally immune donors. T cell recognition of specific peptides was concordant between naive, DC-mediated responses, and postvaccine responses using monocytes as APC in 69% of comparisons (p = 0.05; chi2); the predictive value of a positive response to an IE62 peptide before immunization for T cell sensitization in vivo was 82%. These observations indicate that primary T cell responses detected in vitro using DC as APC may be useful to characterize the potential immunogenicity of viral protein epitopes in vivo.     

Varicella-zoster virus Fc receptor component gI is phosphorylated on its endodomain by a cyclin-dependent kinase

Varicella-zoster virus (VZV) glycoprotein gI is a type 1 transmembrane glycoprotein which is one component of the heterodimeric gE:gI Fc receptor complex. Like VZV gE, VZV gI was phosphorylated in both VZV-infected cells and gI-transfected cells. Preliminary studies demonstrated that a serine 343-proline 344 sequence located within the gI cytoplasmic tail was the most likely phosphorylation site. To determine which protein kinase catalyzed the gI phosphorylation event, we constructed a fusion protein, consisting of glutathione-S-transferase (GST) and the gI cytoplasmic tail, called GST-gI-wt. When this fusion protein was used as a substrate for gI phosphorylation in vitro, the results demonstrated that GST-gI-wt fusion protein was phosphorylated by a representative cyclin-dependent kinase (CDK) called P-TEFb, a homologue of CDK1 (cdc2). When serine 343 within the serine-proline phosphorylation site was replaced with an alanine residue, the level of phosphorylation of the gI fusion protein was greatly reduced. Subsequent experiments with individually immunoprecipitated mammalian CDKs revealed that the VZV gI fusion protein was phosphorylated best by CDK1, to a lesser degree by CDK2, and not at all by CDK6. Transient-transfection assays carried out in the presence of the specific CDK inhibitor roscovitine strongly supported the prior results by demonstrating a marked decrease in gI phosphorylation while gI protein expression was unaffected. Finally, the possibility that VZV gI contained a CDK phosphorylation site in its endodomain was of further interest because its partner, gE, contains a casein kinase II phosphorylation site in its endodomain; prior studies have established that CDK1 can phosphorylate casein kinase II.     

Varicella-zoster virus: infection, control, and prevention

Varicella-zoster virus is a herpes virus that produces a primary infection, chickenpox, manifested by a vesicular eruption and is considered one of the common childhood infectious diseases. After the initial infection the virus becomes latent, then when activated it is manifested as herpes zoster, commonly known as shingles. This highly communicable human disease is associated with serious morbidity and significant mortality, particularly among the immunocompromised. When introduced in the hospital, significant disruptions occur and serious sequelae may results. Recently, a live virus varicella vaccine was approved by the Food and Drug Administration in the United States. Studies have shown the vaccine to be safe and effective. Widespread use of this vaccine may be beneficial in reducing the opportunities for varicella-zoster virus introductions in health care settings.     

Protective immunity of bovine herpesvirus-1 (BHV-1) recombinants which express pseudorabies virus (PRV) glycoproteins gB, gC, gD and gE

We have constructed recombinants of bovine herpesvirus-1 (BHV-1) which express pseudorabies virus (PRV) gB, gC, gD or gE either individually or in combination. To test the protective immunity, mice were inoculated with these BHV-1 recombinants and challenged three weeks later with virulent PRV. A BHV-1 recombinant, BHV-1/TF7-1, which express PRV gC, gD, gE and gI but not PRV gB, protected all 7 mice from the challenge with 20 LD50 virulent PRV and 6 out of 7 from the challenge with 100 LD50 PRV, while one dead mice survived for 5 days after the challenge. All the control mice died in 3 days. BHV-1 recombinants which express PRV gB, gC and gD individually also gave some protection but not so effective as BHV/TF7-1. Before challenging with virulent PRV, sera were collected from immunized mice and antibody against PRV was assayed. Western blot analyses indicated that all the recombinants induced antibody in mice against PRV gB, gC or gD individually or in combination. Virus neutralizing (VN) titer against PRV was highest in mice which were inoculated with BHV-1/TF6-1, which expresses PRV gB. BHV-1/TF7-1, which was more effective to protect mice from the challenge of virulent PRV, induced lower VN titer.     

The ORF47 and ORF66 putative protein kinases of varicella-zoster virus determine tropism for human T cells and skin in the SCID-hu mouse

The varicella-zoster virus (VZV) genes ORF47 and ORF66 are predicted to encode serine/threonine protein kinases, which are homologs of herpes simplex virus 1 (HSV-1) UL13, and US3. When mutants were constructed by inserting stop codons into ORF47 and ORF66, the recombinants ROka47S and ROka66S, as well as intact ROka replicated in tissue culture. In contrast, inoculation of human thymus/liver or skin implants in SCID-hu mice showed that ORF47 protein was required for viral growth in human T cells and skin. Eliminating ORF66 expression inhibited VZV infectivity for T cells partially but did not impair replication in skin compared with ROka. Infectivity for T cells and skin was restored when ROka47S virus was complemented by insertion of ORF47 into a distant, noncoding site. The ORF47 gene product is the first VZV protein identified as necessary for T cell tropism. It also is essential for skin infectivity in vivo, as is glycoprotein C. Expression of ORF66 did not compensate for the absence of the ORF47 protein. The requirement for ORF47 expression in T cells and skin indicates that this gene product, which is dispensable in vitro, has a critical role within differentiated cells that are essential targets for VZV pathogenesis in vivo.