Cis and trans elements regulating expression of the varicella zoster virus gI gene

We have identified cis- and trans-acting elements involved in the VZV IE62 protein-activated expression of the varicella zoster virus (VZV) gene which encodes the viral gI glycoprotein. The cis-acting elements include a non-canonical TATA box and a novel 19 base pair sequence located just upstream of the TATA element designated the "activating upstream sequence" or AUS. The AUS is a movable element and its presence results in IE62 activation of a chimeric promoter consisting of the VZV gC TATA box and the gI AUS. We have also determined that the VZV ORF 29 protein modulates the regulatory activity of the IE62 protein at the gI promoter. In combination with the IE62 transactivator, it yields a 10 to 15-fold increase in expression over the levels seen with the IE62 protein alone in T lymphocytes. The upmodulatory activity requires the presence of a 40 base pair sequence, designated the 29RE, which maps between positions -220 and -180 in the gI promoter. In this paper we review these and earlier findings from our laboratories concerning the regulation of the gI promoter.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Varicella-zoster virus gene expression in latently infected and explanted human ganglia

A consistent feature of varicella-zoster virus (VZV) latency is the restricted pattern of viral gene expression in human ganglionic tissues. To understand further the significance of this gene restriction, we used in situ hybridization (ISH) to detect the frequency of RNA expression for nine VZV genes in trigeminal ganglia (TG) from 35 human subjects, including 18 who were human immunodeficiency virus (HIV) positive. RNA for VZV gene 21 was detected in 7 of 11 normal and 6 of 10 HIV-positive subjects, RNA for gene 29 was detected in 5 of 14 normal and 11 of 11 HIV-positive subjects, RNA for gene 62 was detected in 4 of 10 normal and 6 of 9 HIV-positive subjects, and RNA for gene 63 was detected in 8 of 17 normal and 12 of 15 HIV-positive subjects. RNA for VZV gene 4 was detected in 2 of 13 normal and 4 of 9 HIV-positive subjects, and RNA for gene 18 was detected in 4 of 15 normal and 5 of 15 HIV-positive subjects. By contrast, RNAs for VZV genes 28, 40, and 61 were rarely or never detected. In addition, immunocytochemical analysis detected the presence of VZV gene 63-encoded protein in five normal and four HIV-positive subjects. VZV RNA was also analyzed in explanted fresh human TG and dorsal root ganglia from five normal human subjects over a period of up to 11 days in culture. We found a very different pattern of gene expression in these explants, with transcripts for VZV genes 18, 28, 29, 40, and 63 all frequently detected, presumably as a result of viral reactivation. Taken together, these data provide further support for the notion of significant and restricted viral gene expression in VZV latency.

Open reading frame S/L of varicella-zoster virus encodes a cytoplasmic protein expressed in infected cells

We report the discovery of a novel gene in the varicella-zoster virus (VZV) genome, designated open reading frame (ORF) S/L. This gene, located at the left end of the prototype VZV genome isomer, expresses a polyadenylated mRNA containing a splice within the 3' untranslated region in virus-infected cells. Sequence analysis reveals significant differences between the ORF S/Ls of wild-type and attenuated strains of VZV. Antisera raised to a bacterially expressed portion of ORF S/L reacted specifically with a 21-kDa protein synthesized in cells infected with a VZV clinical isolate and with the original vaccine strain of VZV (Oka-ATCC). Cells infected with other VZV strains, including a wild-type strain that has been extensively passaged in tissue culture and commercially produced vaccine strains of Oka, synthesize a family of proteins ranging in size from 21 to 30 kDa that react with the anti-ORF S/L antiserum. MeWO cells infected with recombinant VZV harboring mutations in the C-terminal region of the ORF S/L gene lost adherence to the stratum and adjacent cells, resulting in an altered plaque morphology. Immunohistochemical analysis of VZV-infected cells demonstrated that ORF S/L protein localizes to the cytoplasm. ORF S/L protein was present in skin lesions of individuals with primary or reactivated infection and in the neurons of a dorsal root ganglion during virus reactivation.

Detection of herpes simplex virus and varicella-zoster virus in clinical swabs: frequent inhibition of PCR as determined by internal controls

BACKGROUND

PCR-based detection of microorganisms is widely used for diagnostic purposes. Most routine PCR applications do not control for inhibition of PCR, thus leading to false-negative results.

METHODS AND RESULTS

One hundred eighteen swab samples obtained from skin and mucosa were investigated for the presence of herpes simplex virus (HSV), varicella-zoster virus (VZV), and the control gene betaglobin by internally controlled PCR with purified and unpurified DNA in parallel. With unpurified DNA, inhibition of PCR was detected in 23% of betaglobin PCRs, 25% of VZV PCRs, and 16% of HSV PCRs versus 3% each for purified DNA. Approximately 20% of the samples with positive results for HSV or VZV had negative or inhibited results using unpurified DNA.

CONCLUSION

These results indicate that PCR from clinical swab specimens should be performed exclusively with internal controls because the positive control alone cannot exclude PCR inhibition in individual samples. Purification of DNA will decrease, but not exclude, PCR inhibition.

Rapid genotyping of varicella-zoster virus vaccine and wild-type strains with fluorophore-labeled hybridization probes

We developed a single-tube rapid method for the detection and differentiation of varicella-zoster virus (VZV) vaccine and wild-type strains that combines rapid-cycle PCR with wild-type-specific fluorescent probe melting profiles for product genotyping. A region including the polymorphic site in VZV open reading frame (ORF) 62 was amplified in the presence of two fluorescence-labeled hybridization probes. During the annealing step of the thermal cycling, both probes bound to their complementary sequences in the amplicon, resulting in resonance energy transfer, thus providing real-time fluorescence monitoring of PCR. Continuous acquisition of fluorescence data during a melting curve analysis at the completion of PCR revealed that loss of fluorescence occurred in a strain-specific manner as the detection probe, which was fully complementary to the wild-type VZV ORF 62 region, melted off the template. Use of this method allowed genotyping of samples within minutes after the completion of PCR, eliminating the need for post-PCR sample manipulation. In addition to reducing the time required to produce a result, this method substantially reduces the risk of contamination of the final product as well as the risk of sample tracking errors. The genotypes of 79 VZV-positive samples determined by this fluorescent resonance energy transfer (FRET) method were identical to the genotypes obtained by conventional PCR and restriction fragment length polymorphism analysis. The genotyping of VZV strains by the FRET method is a rapid and reliable method that is suitable for typing and that is also practical for use for the processing of large numbers of specimens.

Monitoring four herpesviruses in unrelated cord blood transplantation

Cord blood transplantation, which has lower risk of graft-versus-host disease than bone marrow transplantation, might have higher risk of infections. A system to quantify four herpesviruses, CMV, human herpesvirus 6 (HHV6), EBV, varicella-zoster virus using the real-time PCR assay was established and applied for prospective viral load monitoring in three recipients undergoing cord blood transplantation. CMV and HHV6 were detected in peripheral blood from all three recipients, while EBV was detected in two. Varicella-zoster virus was not detected at all. At the peak of HHV6 or CMV, each patient showed virus-related symptoms. During the pre-transplant period, CMV DNA was detected in two recipients who later developed CMV-related diseases. These observations indicate that our system is not only useful for managing herpesviruses infections in transplant recipients, but also a powerful method for clarifying the relationships between the viral load and clinical symptoms.

The postmarketing safety profile of varicella vaccine

The postmarketing safety profile of varicella vaccine was evaluated by analyzing selected adverse experience reports temporally associated with the administration of the vaccine. There were 7963 reports voluntarily submitted to Merck for an overall reporting rate of 5.0 per 10000 doses of vaccine distributed. A varicella zoster virus (VZV) identification program detected the presence of the Oka vaccine strain in three individuals with an immune deficiency - two with pneumonia and one with hepatitis - and in three instances of secondary transmission from vaccinees with vesicular lesions to susceptible household contacts. The Oka vaccine strain was present in 23 patients and wild-type VZV was present in 15 patients with herpes zoster. Vesicular rashes that occurred within 2 weeks of vaccination were more likely to contain the presence of wild-type VZV, while vesicular rashes that occurred more than 2 weeks post-vaccination were more likely to contain the Oka vaccine strain. Eleven patients were hospitalized with complications of breakthrough varicella infection.

Simultaneous detection of 6 human herpesviruses in cerebrospinal fluid and aqueous fluid by a single PCR using stair primers

A Herpes Consensus allows the simultaneous detection of 6 human herpesviruses: herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), human cytomegalovirus (HCMV), varicella-zoster virus (VZV), Epstein-Barr virus (EBV), and human herpes virus 6 (HHV-6). This technique was used first to examine retrospectively 100 DNA extracts from 95 CSF and 5 aqueous fluids, prepared by treatment by saturated NaCl followed by ethanol precipitation (n = 63) or by simple boiling (n = 37) and stored at -80 degrees C, and secondly to test prospectively 38 CSF samples for which two DNA extracts were prepared with commercially available DNA extraction kits. In all cases, the results were compared with those of an "in-house" PCR. Concordant results between both PCR and the Herpes Consensus techniques were obtained in 61 of 63 DNA extracts prepared by treatment by saturated NaCl (97%) and in only 31 of 37 boiled samples (84%). Both commercially available methods of DNA extraction examined appear to be suitable for Herpes Consensus PCR, although they cannot remove completely PCR inhibitors that must be sought in case of negative results. This preliminary study shows that the Herpes Consensus method should be of value for rapid diagnosis of herpesvirus infections on condition that it is performed on purified DNA extracts.

Primary graft failure : a clinicopathologic and molecular analysis

OBJECTIVE

Primary graft failure (PGF) corneal tissues were analyzed for herpes simplex virus (HSV) and varicella-zoster virus (VZV).

DESIGN

Retrospective, noncomparative case series.

MATERIALS

Formalin-fixed, paraffin-embedded tissue of 21 donor corneas and 14 recipient corneas of PGF cases, as well as 10 control corneas.

METHODS

Clinical, histologic, immunohistochemical, polymerase chain reaction (PCR), and, in selected cases, transmission electron microscopic characteristics were studied.

MAIN OUTCOME MEASURES

Evidence of HSV or VZV in donor tissues.

RESULTS

Median patient age was 65 years, and median donor age was 48 years. Donor cornea parameters, including endothelial cell counts, death-to-preservation time, and time in storage, were generally within accepted standards. Stromal edema was found in all 21 donor corneas with PGF. Eighteen donor corneas demonstrated severely reduced or absent endothelium and mild to moderate lymphocytic infiltration without necrosis. Three donor corneas (14%) had necrotizing stromal keratitis (NSK) with keratic precipitates. Positive immunohistochemical staining of keratocytes for HSV was present in two of two donor corneas with NSK and was negative in 18 other donor corneas. Polymerase chain reaction analysis revealed the DNA of HSV type 1 (HSV1) in all donor corneas with NSK and in four donor corneas without NSK (33%). Recipient corneal tissue was negative for HSV1 DNA in three patients with NSK and positive in two of the four other PCR-positive patients. Transmission electron microscopy analysis showed viral particles in two donor corneas with NSK. Polymerase chain reaction analysis revealed no evidence of HSV type 2 or VZV in any cornea. All control corneas were negative for viral DNA. Sixteen corneas remained clear and two had failed after regraft for PGF, with a median follow-up of 3.6 years.

CONCLUSIONS

Herpes simplex virus type 1 DNA was present in 33% of patients of PGF. Herpetic stromal keratitis was found in some failed corneas; the lack of HSV in the paired recipient suggests importation within the donor cornea. The overall prognosis for regrafting after PGF is good.

The role of cellular- and prodrug-associated factors in the bystander effect induced by the Varicella zoster and Herpes simplex viral thymidine kinases in suicide gene therapy

To investigate the factors influencing the bystander effect--a key element in the efficacy of suicide gene therapy against cancer--we compared the effect triggered by four extremely efficient gene/prodrug combinations, i.e., VZVtk/BVDU, the thymidine kinase of Varicella zoster virus associated with (E)-5-(2-bromovinyl)-2'-deoxyuridine; VZVtk/BVaraU, the same enzyme associated with (E)-5-(2-bromovinyl)-1-beta-D-arabinofuranosyluracil; HSVtk/BVDU, the association of the Herpes simplex virus thymidine kinase with BVDU; and the classical HSVtk/GCV (ganciclovir) paradigm. The cells used, the human MDA-MB-435 breast cancer, and the rat 9L glioblastoma lines were equally sensitive in vitro to these four associations. In both cell types, the combinations involving pyrimidine analogues (BVDU, BVaraU) displayed a smaller bystander killing than the combination involving the purine analogue (GCV). In addition, the bystander effect induced by all the tk/prodrug systems was reduced in MDA-MB-435 cells in comparison to 9L cells; albeit, the viral kinases were produced at a higher level in the breast cancer cells. All systems induced apoptotic death in the two cell types, but the MDA-MB-435 cells, deprived of connexin 43, were noncommunicating in striking contrast with the 9L cells. That functional gap junctions have to be increased in order to improve the breast cancer cell response to suicide gene therapy was demonstrated by transducing the Cx43 gene: this modification enhanced the bystander effect associated in vitro with GCV treatment and, by itself, decreased the tumorigenicity of the untreated cells. However, the noncommunicating MDA-MB-435 cells triggered a significant bystander effect both in vitro and in vivo with the HSVtk/GCV system, showing that communication through gap junctions is not the only mechanism involved.

Herpesvirus DNA detection in cerebral spinal fluid: differences in clinical presentation between alpha-, beta-, and gamma-herpesviruses

To evaluate the role of 6 human herpesviruses (cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus-6 (HHV-6), herpes simplex virus (HSV) types 1 and 2 and varicella zoster virus (VZV)) in infections of the nervous system, cerebrospinal fluid (CSF) samples from 662 patients with suspected viral aetiology to neurological symptoms were investigated for presence of herpesviral DNA in a PCR-based study. Of the 69 patients (2 patients had 2 herpesvirus DNA detected in CSF) who had herpesvirus DNA detected in the CSF, 60 (87%) were non-immunocompromised (CMV 7; HHV-6 6; EBV 16; HSV-1 18; HSV-2 9 and VZV 6) and 9 (13%) were immunocompromised (CMV 3; HHV-6 0; EBV 5; HSV-1 0; HSV-2 1 and VZV 0). The study was performed in a retrospective/prospective manner. The HSV-1, HSV-2, VZV and CMV DNA-positive patients usually had typical clinical syndromes, such as encephalitis/myelitis and meningitis, but also other neurological conditions were associated with findings of these viruses. HHV-6 and EBV DNA were detected in patients presenting with a variety of neurological symptoms, and in some of the cases, concurrent with diagnosis of other infections of the central nervous system. Despite the overall variability of clinical conditions seen, a pattern associated with each investigated herpesvirus was discernable as regards clinical presentation.

Gene activation by Varicella-zoster virus IE4 protein requires its dimerization and involves both the arginine-rich sequence, the central part, and the carboxyl-terminal cysteine-rich region

Varicella-zoster virus (VZV) open reading frame 4-encoded protein (IE4) possesses transactivating properties for VZV genes as well as for those of heterologous viruses. Since most transcription factors act as dimers, IE4 dimerization was studied using the mammalian two-hybrid system. Introduction of mutations in the IE4 open reading frame demonstrated that both the central region and the carboxyl-terminal cysteine-rich domain were important for efficient dimerization. Within the carboxyl-terminal domain, substitution of amino acids encompassing residues 443-447 totally abolished dimerization. Gene activation by IE4 was studied by transient transfection with an IE4 expression plasmid and a reporter gene under the control of either the human immunodeficiency virus, type 1, long terminal repeat or the VZV thymidine kinase promoter. Regions of IE4 important for dimerization were also shown to be crucial for transactivation. In addition, the arginine-rich domains Rb and Rc of the amino-terminal region were also demonstrated to be important for transactivation, whereas the Ra domain as well as an acidic and bZIP-containing regions were shown to be dispensable for gene transactivation. A nucleocytoplasmic shuttling of IE4 has also been characterized, involving a nuclear localization signal identified within the Rb domain and a nuclear export mechanism partially depending on Crm-1.

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.

Varicella zoster meningoencephalitis following treatment for dermatomal zoster in an alloBMT patient

Herpes zoster infections are frequently observed after allogeneic bone marrow transplantation (alloBMT). In the majority of cases, the infection is restricted to specific dermatomes and responds to oral acyclovir, without visceral dissemination. We report the case of a 40-year-old male who developed dermatomal herpetic infection 8 months post alloBMT. The herpetic rash responded well to treatment with high-dose oral acyclovir. However, within a week of cessation of therapy, the patient re-presented with dermatomal zoster and meningoencephalitis. Although the cutaneous lesions resolved with intravenous acyclovir, clinical features of meningoencephalitis persisted, along with evidence of varicella zoster virus (VZV) DNA in cerebrospinal fluid (CSF). A satisfactory response to treatment was observed only after the addition of intravenous foscarnet to acyclovir. Based on our experience with this patient, we suggest that in a subset of alloBMT recipients, late dermatomal herpes zoster infections may respond only partially to treatment with standard oral acyclovir. The use of oral acyclovir preparations with higher bioavailability (valacyclovir) or intravenous acyclovir early on may prevent the considerable morbidity associated with disseminated zoster infection. Bone Marrow Transplantation (2000) 26, 795-796.

A single tube PCR assay for simultaneous amplification of HSV-1/-2, VZV, CMV, HHV-6A/-6B, and EBV DNAs in cerebrospinal fluid from patients with virus-related neurological diseases

Cerebrospinal fluid (CSF) specimens from 27 patients with encephalitis, meningitis, and other neurological diseases were studied for the presence of herpes simplex virus types 1 and 2 (HSV-1/-2), varicella-zoster virus (VZV), cytomegalovirus (CMV), human herpesviruses 6A and 6B (HHV-6A/-6B) and Epstein-Barr virus (EBV) DNA using the polymerase chain reaction (PCR) method. The DNAs were amplified using two sets of consensus primer pairs in a single tube, bringing simultaneous amplification of the herpesviruses. The PCR products were analyzed by agarose gel electrophoresis, and Southern blot hybridization with virus-type specific probes, thus allowing discrimination between the different types of herpesviruses to be made. Each virus-specific probe was highly specific for identifying the PCR product. Thirty CSF specimens from 13 patients with encephalitis and 10 specimens from 10 patients with meningitis, respectively, were examined using this method. Eight patients with encephalitis and six with meningitis were positive for different herpesviruses, including patients with coinfections (HSV-1/-2 and VZV, VZV and CMV). Among four CSF specimens from four patients with other neurological disorders, dual amplification of CMV and EBV was present. Since identification of the types of herpesviruses in this system requires a very small amount of CSF, and is completed with one PCR, it is useful for routine diagnosis of herpesvirus infections in diagnostic laboratories. The viruses responsible for central nervous system infection are easily detected with various coinfection and serial patterns of herpesviruses, by this consensus primer-based PCR method. This may give an insight into the relationship between virus-related neurological diseases (VRNDS) and herpesvirus infections.

Varicella-zoster virus gE escape mutant VZV-MSP exhibits an accelerated cell-to-cell spread phenotype in both infected cell cultures and SCID-hu mice

Varicella-zoster virus is considered to have one of the most stable genomes of all human herpesviruses. In 1998, we reported the unanticipated discovery of a wild-type virus that had lost an immunodominant B-cell epitope on the gE ectodomain (VZV-MSP); the gE escape mutant virus exhibited an unusual pattern of egress. Further studies have now documented a markedly enhanced cell-to-cell spread by the mutant virus in cell culture. This property was investigated by laser scanning confocal microscopy combined with a software program that allows the measurement of pixel intensity of the fluorescent signal. For this new application of imaging technology, the VZV immediate early protein 62 (IE 62) was selected as the fluoresceinated marker. By 48 h postinfection, the number of IE 62-positive pixels in the VZV-MSP-infected culture was nearly fourfold greater than the number of pixels in a culture infected with a low-passage laboratory strain. Titrations by infectious center assays supported the above image analysis data. Confirmatory studies in the SCID-hu mouse documented that VZV-MSP spread more rapidly than other VZV strains in human fetal skin implants. Generally, the cytopathology and vesicle formation produced by other strains at 21 days postinfection were demonstrable with VZV-MSP at 14 days. To assess whether additional genes were contributing to the unusual VZV-MSP phenotype, approximately 20 kb of the VZV-MSP genome was sequenced, including ORFs 31 (gB), 37 (gH), 47, 60 (gL), 61, 62 (IE 62), 66, 67 (gI), and 68 (gE). Except for a few polymorphisms, as well as the previously discovered mutation within gE, the nucleotide sequences within most open reading frames were identical to the prototype VZV-Dumas strain. In short, VZV-MSP represents a novel variant virus with a distinguishable phenotype demonstrable in both infected cell cultures and SCID-hu mice.

Improved identification and differentiation of varicella-zoster virus (VZV) wild-type strains and an attenuated varicella vaccine strain using a VZV open reading frame 62-based PCR

A new method was developed to identify and differentiate varicella-zoster virus (VZV) wild-type strains from the attenuated varicella Oka vaccine strain. The PCR technique was used to amplify a VZV open reading frame (ORF) 62 region. A single specific amplicon of 268 bp was obtained from 71 VZV clinical isolates and several laboratory strains. Subsequent digestion of the VZV ORF 62 amplicons with SmaI enabled accurate strain differentiation (three SmaI sites were present in amplicons of vaccine strain VZV, compared with two enzyme cleavage sites for all other VZV strains tested). This method accurately differentiated the Oka vaccine strain from wild-type VZV strains circulating in countries representing all six populated continents. Moreover, the assay more reliably distinguished wild-type Japanese strains from the vaccine strain than did previously described methods.

Diagnosis of varicella-zoster virus infections in the clinical laboratory by LightCycler PCR

Varicella-zoster virus (VZV) causes vesicular dermal lesions which are clinically evident as varicella (primary infection) or zoster (reactivated) diseases. The LightCycler system (Roche Molecular Biochemicals) is a newly developed commercially available system designed to rapidly perform PCR with real-time detection of PCR products using a fluorescence resonance energy transfer. We compared the detection of VZV from dermal specimens by shell vial cell culture (MRC-5) and by LightCycler PCR. Of 253 specimens, VZV was detected in 23 (9.1%) by shell vial cell cultures and 44 (17.4%) by LightCycler PCR directed to a nucleic acid target sequence in gene 28. Twenty-one of 44 (47.7%) specimens were exclusively positive by LightCycler PCR; the shell vial cell culture assay was never positive when DNA amplification was negative (specificity, 100%). VZV DNA was detected in 39 of 44 (88.6%) specimens positive during cycles 10 through 30 of the LightCycler PCR. These VZV DNA-positive specimens (cycles 10 to 30) and 5 of 11 other PCR positive specimens (cycles 31 to 36) were confirmed by another LightCycler PCR directed to another (gene 29) target of the viral genome. For routine laboratory practice, all specimens yielding amplified DNA to the VZV gene 28 target can be considered positive results. The increased sensitivity (91%) of the LightCycler PCR for detection of VZV, rapid turnaround time for reporting results, virtual elimination of amplicon carryover contamination, and equivalent costs compared to shell vial cell culture for detection of VZV indicate the need for implementation of this technology for routine laboratory diagnosis of this viral infection.

Acute retinal necrosis following contralateral herpes zoster ophthalmicus

BACKGROUND

A case report of contralateral acute retinal necrosis (ARN) following herpes zoster ophthalmicus.

CASE

A 61-year-old male patient developed iridocyclitis and well-demarcated creamy-white retinal lesions at the nasal periphery in the right eye 1 month after herpes zoster ophthalmicus in the left eye. The patient had undergone surgery for primary lung cancer, and had subsequent intracranial metastasis of the tumor.

OBSERVATIONS

The clinical diagnosis of ARN was supported by polymerase chain reaction investigation of the aqueous humor resulting in positive for varicella-zoster virus. Retinal lesions disappeared after systemic treatment with acyclovir, corticosteroids, and acetylsalicylate. No retinal detachment developed.

CONCLUSIONS

We propose a careful ophthalmic follow-up for herpes zoster ophthalmicus patients because of the possibility of acute retinal necrosis developing in the contralateral eye.

Sequence analysis of the leftward end of simian varicella virus (EcoRI-I fragment) reveals the presence of an 8-bp repeat flanking the unique long segment and an 881-bp open-reading frame that is absent in the varicella zoster virus genome

Simian varicella virus (SVV) causes varicella (chickenpox) in nonhuman primates, becomes latent in cranial and dorsal root ganglia, and reactivates to produce zoster (shingles). Because the clinical and molecular features of SVV closely resemble those of varicella zoster virus (VZV) infection of humans, SVV infection of primates has served as an experimental model of VZV pathogenesis and latency. The SVV genome has been completely mapped, but attempts to clone the 3600-bp EcoRI fragment located at the leftward end of the virus genome have hitherto been unsuccessful. Herein, we report the cloning and the complete nucleotide sequence of this region. Comparison of the SVV and VZV sequences in this region revealed an 8-bp inverted repeat sequence flanking the unique long segment of the SVV genome; an 879-bp open-reading frame (ORF) A in SVV that is absent in VZV but has 42% amino acid identity to SVV ORF 4 and 49% to VZV ORF 4; a 342-bp ORF B in SVV with 35% amino acid identity to a 387-bp ORF located to the left of ORF 1 on the VZV genome; and a 303-bp ORF in SVV with 27% amino acid identity to VZV ORF 1. No homologue of VZV ORF 2 was detected. Transcripts specific for ORFs A and B were present in SVV-infected cells in culture and in acutely infected monkey ganglia. Overall, there are more than 2000 bp of DNA in the SVV genome that are absent in the VZV genome.

Varicella-zoster virus infections in pregnancy

Chickenpox is an uncommon disease in women during pregnancy. If, however, maternal varicella infects the fetus, intrauterine death or severe diseases (congenital or fetal varicella syndrome) may ensue depending on the time of maternal infection. On the basis of our own clinical observations and virological testing we report on 31 women with varicella during pregnancy and their infants. Five neonates born to mothers with varicella between the 8th and 21st week showed clinical signs of the congenital varicella syndrome. Varicella-zoster virus DNA could be detected in different tissues, including lung, liver, skin and adrenal glands. As a consequence of maternal chickenpox within 12 days before delivery, 6 newborn babies developed neonatal varicella. Measures for diagnosis, treatment and prophylaxis are discussed.

Subclinical reactivation of varicella-zoster virus in immunocompromised and immunocompetent individuals

The occurrence of subclinical reactivation of varicella-zoster virus (VZV) in peripheral blood mononuclear cells (PBMC) from immunocompetent subjects >60 years old without any signs of VZV-caused illnesses, and from immunocompromised patients was investigated. Altogether, 223 samples were tested by nested ORF 63 PCR assay. In addition, all positive samples were tested by ORF 14, ORF 29 and ORF 63 PCR assays, as well as by ORF 63 and ORF 68 nucleic acid sequence-based amplification assays. In 5 samples, VZV-specific DNA, but no transcripts, could be detected. Three of them belonged to the group of >60-year-olds, 1 was HIV positive, the other was being treated with chemotherapy. The results confirm the observation of other authors that subclinical reactivation occurs in both immunocompromised and healthy individuals. The failure to detect DNA in samples taken from 2 individuals several weeks later excludes a long-lasting infection of VZV in PBMC.