Antibody responses to varicella-zoster virus and the role of antibody in host defense

Diagnostic Methods and Management Strategies of Herpes Simplex and Herpes Zoster Infections

Herpesviruses are medium-sized double-stranded DNA viruses. Of more than 80 herpesviruses identified, only 9 human herpesviruses have been found to cause infection in humans. These include herpes simplex viruses 1 and 2 (HSV-1 and HSV-2), varicella-zoster virus (VZV), human cyto-megalovirus (HCMV), Epstein-Barr virus (EBV), and human herpesvirus (HHV-6A, HHV-6B, HHV-7, HHV-8). HSV-1, HSV-2, and VZV can be problematic given their characteristic neurotropism which is the ability to invade via fusion of its plasma membrane and reside within neural tissue. HSV and VZV primarily infect mucocutaneous surfaces and remain latent in the dorsal root ganglia for a host's entire life. Reactivation causes either asymptomatic shedding of virus or clinical manifestation of vesicular lesions. The clinical presentation is influenced by the portal of entry, the immune status of the host, and whether the infection is primary or recurrent. Affecting 60% to 95% of adults, herpesvirus-associated infections include gingivostomatitis, orofacial and genital herpes,and primary varicella and herpes zoster. Symptomatology, treatment, and potential complications vary based on primary and recurrent infections as well as the patient's immune status.

Comparison of the Immune Effects of an mRNA Vaccine and a Subunit Vaccine against Herpes Zoster Administered by Different Injection Methods

Previous studies have shown that the herpes zoster subunit vaccine Shingrix™ performs well in clinical trials. However, the key ingredient in its adjuvant, QS21, is extracted from rare plants in South America, so vaccine production is limited. Compared with subunit vaccines, mRNA vaccines have the advantages of faster production and not requiring adjuvants, but currently, there is no authorized mRNA vaccine for herpes zoster. Therefore, this study focused on herpes zoster subunit and mRNA vaccines. We prepared a herpes zoster mRNA vaccine and compared the effects of vaccine type, immunization route, and adjuvant use on vaccine immunological efficacy. The mRNA vaccine was injected directly into mice via subcutaneous or intramuscular injection. The subunit vaccine was mixed with adjuvants before immunization. The adjuvants include B2Q or alum. B2Q is BW006S + 2395S + QS21. BW006S and 2395S are phosphodiester CpG oligodeoxynucleotides (CpG ODNs). Then, we compared the cell-mediated immunity (CIM) and humoral immunity levels of the different groups of mice. The results showed that the immune responses of mice inoculated with the mRNA vaccine prepared in this study were not significantly different from those of mice inoculated with the protein subunit vaccine supplemented with the B2Q. The mRNA vaccine-induced immune responses following subcutaneous or intramuscular injection, and the different immunization routes did not lead to significant differences in immune response intensity. Similar results were also observed for the protein subunit vaccine adjuvanted with B2Q but not alum. The above results suggest that our experiment can provide a reference for the preparation of mRNA vaccines against herpes zoster and has certain reference significance for the selection of the immunization route; that is, there is no significant difference in the immune response caused by subcutaneous versus an intramuscular injection, so the injection route can be determined according to the actual situation of individuals.

Diagnostic methods and management strategies of herpes simplex and herpes zoster infections

Herpes infections are extremely prevalent in the adult population. Recognizing early signs and symptoms is essential to provide effective treatment. The immunocompromised population presents treatment challenges requiring prolonged antiviral therapy and more frequent recurrences. Viral culture is often considered the gold standard diagnostic technique; however, polymerase chain reaction (PCR) should be done in tandem with culture especially for varicella zoster virus infections. Antivirals can decrease viral shedding, recurrences of herpes simplex, and hasten healing of herpes zoster. Herpes virus can be a challenging entity to treat with significant morbidity (both physically and psychologically).

Age and immune status of rhesus macaques impact simian varicella virus gene expression in sensory ganglia

Simian varicella virus (SVV) infection of rhesus macaques (RMs) recapitulates the hallmarks of varicella-zoster virus (VZV) infection of humans, including the establishment of latency within the sensory ganglia. Various factors, including age and immune fitness, influence the outcome of primary VZV infection, as well as reactivation resulting in herpes zoster (HZ). To increase our understanding of the role of lymphocyte subsets in the establishment of viral latency, we analyzed the latent SVV transcriptome in juvenile RMs depleted of CD4 T, CD8 T, or CD20 B lymphocytes during acute infection. We have previously shown that SVV latency in sensory ganglia of nondepleted juvenile RMs is associated with a limited transcriptional profile. In contrast, CD4 depletion during primary infection resulted in the failure to establish a characteristic latent viral transcription profile in sensory ganglia, where we detected 68 out of 69 SVV-encoded open reading frames (ORFs). CD-depleted RMs displayed a latent transcriptional profile that included additional viral transcripts within the core region of the genome not detected in control RMs. The latent transcriptome of CD20-depleted RMs was comparable to the latent transcription in the sensory ganglia of control RMs. Lastly, we investigated the impact of age on the establishment of SVV latency. SVV gene expression was more active in ganglia from two aged RMs than in ganglia from juvenile RMs, with 25 of 69 SVV transcripts detected. Therefore, immune fitness at the time of infection modulates the establishment and/or maintenance of SVV latency.

Varicella zoster virus (VZV) and herpes simplex virus (HSV) in solid organ transplant patients

Varicella zoster virus (VZV) and the two herpes simplex viruses (HSV) are human α-herpesviruses that establish life-long latency in neural ganglia after initial primary infection. In the solid organ transplant (SOT) population, manifestations of VZV or HSV may be seen in up to 70% of recipients if no prophylaxis is used, some of them life and organ threatening. While there are effective vaccines to prevent VZV primary infection and reactivation in immunocompetent adults, these vaccines are contraindicated after SOT because they are live-virus vaccines. For HSV, prevention has focused primarily on antiviral strategies because the immunologic correlates of protection and control are different from VZV, making vaccine development more challenging. Current antiviral therapy remains effective for the majority of clinical VZV and HSV infections.

Measurement of varicella-zoster virus (VZV)-specific cell-mediated immunity: comparison between VZV skin test and interferon-gamma enzyme-linked immunospot assay

Cell-mediated immunity (CMI) is critical for the prevention and control of varicella-zoster virus (VZV)-related disease. To assess CMI to VZV, a varicella skin test and interferon-gamma enzyme-linked immunospot (ELISPOT) assay were both performed in healthy volunteers, and the results were compared. A total of 151 subjects were examined: 16 aged 20-29 years, 26 aged 30-39 years, 18 aged 40-49 years, 73 aged 50-59 years, and 18 aged 60-69 years. All were seropositive by a glycoprotein antigen-based enzyme-linked immunosorbent assay (gpELISA). Skin test reactivity was significantly correlated with the ELISPOT count, and both decreased with increasing age, indicating an age-dependent decline in CMI to VZV. In contrast, the antibody titer obtained by the gpELISA did not correlate with skin test reactivity. The results suggest that the skin test and ELISPOT assay are both reliable for assessing CMI to VZV and can easily be applied to screen individuals susceptible to the development of herpes zoster.

The neurotropic herpes viruses: herpes simplex and varicella-zoster

Herpes simplex viruses types 1 and 2 (HSV1 and HSV2) and varicella-zoster virus (VZV) establish latent infection in dorsal root ganglia for the entire life of the host. From this reservoir they can reactivate to cause human morbidity and mortality. Although the viruses vary in the clinical disorders they cause and in their molecular structure, they share several features that affect the course of infection of the human nervous system. HSV1 is the causative agent of encephalitis, corneal blindness, and several disorders of the peripheral nervous system; HSV2 is responsible for meningoencephalitis in neonates and meningitis in adults. Reactivation of VZV, the pathogen of varicella (chickenpox), is associated with herpes zoster (shingles) and central nervous system complications such as myelitis and focal vasculopathies. We review the biological, medical, and neurological aspects of acute, latent, and reactivated infections with the neurotropic herpes viruses.

Anterior Segment and External Ocular Disorders Associated with Human Immunodeficiency Virus Disease

The eye is a common site for complications of human immunodeficiency virus (HIV) infection. Although cytomegalovirus retinitis remains the most prevalent of the blinding ocular disorders that can occur in individuals with the acquired immunodeficiency syndrome (AIDS), several important HIV-associated disorders may involve the anterior segment, ocular surface, and adnexae. Some of these entities, such as Kaposi sarcoma, were well described, but uncommon, before the HIV epidemic. Others, like microsporidial keratoconjunctivitis, have presentations that differ between affected individuals with HIV disease and those from the general population who are immunocompetent. The treatment of many of these diseases is challenging because of host immunodeficiency. Survival after the diagnosis of AIDS has increased among individuals with HIV disease because of more effective antiretroviral therapies and improved prophylaxis against, and treatment of, opportunistic infections. This longer survival may lead to an increased prevalence of anterior segment and external ocular disorders. In addition, the evaluation and management of disorders such as blepharitis and dry eye, which were previously overshadowed by more severe, blinding disorders, may demand increased attention, as the general health of this population improves. Not all individuals infected with HIV receive potent antiretroviral therapy, however, because of socioeconomic or other factors, and others will be intolerant of these drugs or experience drug failure. Ophthalmologists must, therefore, still be aware of the ocular findings that develop in the setting of severe immunosuppression. This article reviews the spectrum of HIV-associated anterior segment and external ocular disorders, with recommendations for their evaluation and management.

Preventing varicella-zoster disease

Varicella-zoster virus (VZV), the cause of chickenpox and shingles, is a pathogen in retreat following the introduction of mass vaccination in the United States in 1995. The live attenuated Oka vaccine, which is safe and immunogenic, gives good protection against both varicella and zoster in the short to medium term. It has undoubtedly been highly effective to date in reducing all forms of varicella, especially severe disease. However, the huge pool of latent wild-type virus in the population represents a continuing threat. Both the biology and the epidemiology of VZV disease suggest that new vaccination strategies will be required over time.

Shingles Immunity and Health Functioning in the Elderly: Tai Chi Chih as a Behavioral Treatment

Both the incidence and severity of herpes zoster (HZ) or shingles increase markedly with increasing age in association with a decline in varicella zoster virus (VZV)-specific immunity. Considerable evidence shows that behavioral stressors, prevalent in older adults, correlate with impairments of cellular immunity. Moreover, the presence of depressive symptoms in older adults is associated with declines in VZV-responder cell frequency (VZV-RCF), an immunological marker of shingles risk. In this review, we discuss recent findings that administration of a relaxation response-based intervention, tai chi chih (TCC), results in improvements in health functioning and immunity to VZV in older adults as compared with a control group. TCC is a slow moving meditation consisting of 20 separate standardized movements which can be readily used in elderly and medically compromised individuals. TCC offers standardized training and practice schedules, lending an important advantage over prior relaxation response-based therapies. Focus on older adults at increased risk for HZ and assay of VZV-specific immunity have implications for understanding the impact of behavioral factors and a behavioral intervention on a clinically relevant end-point and on the response of the immune system to infectious pathogens.

Use of varicella vaccines to prevent herpes zoster in older individuals

It is likely that the frequency and severity of herpes zoster in older people is the result of an age-related decline in varicella-zoster virus-specific T-cell mediated immunity. Numerous trials of vaccines to boost these responses have demonstrated their safety and immunogenicity. Both live attenuated and inactivated vaccines have been studied. Persistence of booster responses is dose-related, and the half-life of some boosted measures of T-cell mediated immunity exceeds 5 years. Although these trials have been hampered by uncertainty about the critical immune responses to evaluate, the stage is set for a double-blind, placebo-controlled trial of sufficient size to determine efficacy. Such a trial is now underway.

Varicella zoster viral disease

Herpes zoster is cause of considerable morbidity, especially among elderly patients, with a suggestion of a slight increase in incidence among female patients. Substantial research on the biology of the varicella zoster virus has led to advances in our knowledge of the pathophysiology of the disease along with more successful therapy for the acute episodes of herpes zoster. Ophthalmic zoster is more common than zoster in other cranial nerves and is associated with pronounced suffering. This article reviews the epidemiology, biology, and latency of herpes zoster, discusses the pathophysiology of the disease, and describes treatment options with antivirals and corticosteroids. The pathophysiology and treatment options for postherpetic neuralgia are also addressed. The varicella vaccine is now available, and initial results suggest that this may lessen the effect of herpes zoster in the future.

The varicella vaccine. Prevention of herpes zoster

The live attenuated varicella vaccine offers some hope that the frequency or severity of herpes zoster might be reduced. Universal immunization with this vaccine should result in less latent varicella-zoster virus in dorsal root and cranial nerve ganglia than that which occurs following varicella. Moreover, the vaccine virus is not well adapted for growth in human cells at normal body temperature. Thus, reduced virus for reactivation, and less robust replication, may lessen the problem of herpes zoster in vaccinees. For those individuals who have already had varicella, the risk of herpes zoster is closely related to the loss of varicella-zoster virus cell-mediated immune responses, which decline with aging (or immune suppression). In aging individuals these immune responses can be enhanced by booster immunization with the varicella vaccine, suggesting that a vaccine to prevent herpes zoster is feasible.

Presumed ophthalmic herpes zoster after contralateral cataract extraction

Herpes zoster ophthalmicus (HZO) may occur spontaneously, but can be precipitated by stress, trauma, debility or systemic illness. A case is here reported of Herpes zoster involving the contralateral eye, associated with a midline skin rash, following cataract extraction under local anaesthesia.

Social epidemiology of chickenpox in two British national cohorts

STUDY OBJECTIVE

To provide a quantitative description of factors independently predictive of reported chickenpox infections in two national cohorts of British children.

DESIGN

Longitudinal cohort study design employing logistic regression analysis of data obtained in the 1970 British Births Survey (later to become the Child Health and Education Study, CHES), and the 1958 British Perinatal Mortality Survey (later to become the National Child Development Survey, NCDS).

SETTINGS

One-week birth cohorts covering the whole of the United Kingdom.

PARTICIPANTS

Data were obtained from questionnaires administered to the carers of 10,196 children born in the UK between 5 and 11 April 1970 (CHES) and 10,927 children born in the UK between 3 and 9 March 1958 (NCDS). These numbers consist of the whole of the surviving cohorts excluding those for whom data were incomplete.

MEASUREMENTS

Biological, social, and medical factors in the parents and children, as recorded by the child's principle carer or from clinical notes.

MAIN RESULTS

Chickenpox by the age of 10 years was reported to be more common in the children of advantaged families (higher social class, higher parental education levels), with a higher prevalence in those parts of the United Kingdom normally associated with affluence, such as the South East and South West of England, and lower rates in Wales and Scotland. Chickenpox by 10 years was also associated with more crowding in the home. A similar but less marked pattern occurred for chickenpox by the age of 11 years in the 1958 NCDS cohort. This social distribution apparently reflected overall rather than age-specific susceptibility.

CONCLUSIONS

The national and international pattern of chickenpox epidemiology indicate that both social and climatological factors may be important in defining groups at risk. Further research is indicated if a vaccination service is to be implemented in this country.

The epidemiology of varicella-zoster virus infections: a mathematical model

Herpes-zoster is caused by the reactivation of varicella-zoster virus (VZV). In this paper different hypotheses of how this re-emergence of virus comes about are reviewed and discussed. From these hypotheses, and epidemiological data describing the initial transmission of the virus, a mathematical model of primary disease (varicella) and reactivated disease (zoster) in developed countries is derived. The steady-state age distributions of zoster cases predicted by this model are compared with the observed distribution, derived from a review and analysis of published epidemiological data. The model allows differentiation between published hypotheses in which age of host may or may not influence the probability of viral reactivation. The results indicate that the probability of reactivation must increase with age to allow the observed pattern of zoster cases. The basic mathematical model presented provides a conceptual framework, which may be extended to assess possible control programmes.

Low antibody avidity in elderly chickenpox patients

A small outbreak of chickenpox confirmed serologically in 3 elderly patients from a geriatric home is described. Disease was probably due to exogenous reinfection, yet nevertheless the avidity of specific antibodies measured by the urea denaturation test was even lower than in primary chickenpox controls, which themselves were, as expected, significantly lower than zoster controls. In elderly individuals susceptibility to reinfection with varicella-zoster virus (VZV) with clinical manifestation such as chickenpox may well be associated with the decay of specific humoral immunity detectable by antibodies of particularly low avidity, in contrast to reactivation of latent VZV presenting clinically as zoster, which is related to deficiencies in specific cellular immunity.

Diagnosis and therapy of herpes zoster ophthalmicus

Studies in the basic and clinical sciences have yielded new information about the biology, infection, latency, and recurrence of the varicella-zoster virus. Contrast is made with the herpes simplex virus. The host-viral relationship is an extremely dynamic one with clinical disease being determined primarily by the host cellular immune system. The complications of herpes zoster ophthalmicus are related to multiple mechanisms including viral growth, vascular and neural damage, and the host-immune response to infection. There are several laboratory tests available for confirming the diagnosis or determining the immune status. Systemic acyclovir administered early in the course alleviates many of the symptoms of herpes zoster ophthalmicus. Acute and postherpetic neuralgia remain significant and enigmatic problems; an update of therapeutic options is offered. The role of corticosteroids in herpes zoster ophthalmicus is scrutinized along with the potential and uncertainties of a varicella-zoster virus vaccine.

Natural killing of varicella-zoster virus (VZV)-infected fibroblasts in normal children, children with VZV infections, and children with Hodgkin's disease

We studied mononuclear cell (MNC)-mediated natural killing (NK) of varicella-zoster virus (VZV)-infected fibroblasts in normal children, children with VZV infections, and children with Hodgkin's disease. NK activity was tested in 18 hr 51Cr release assays. NK activity for adults was significantly higher than that for children 1-3 years old or 4-6 years old (p less than 0.05). Serological status did not affect NK activity. NK activity in normal children was not increased 4-6 weeks after immunization with varicella vaccine. Seven normal children with natural varicella showed significantly higher NK activity against VZV-infected and uninfected targets. Eight immunosuppressed children with herpes zoster showed significantly reduced NK activity within 72 hours of the onset of herpes zoster. However, their NK activity rose to the normal level one to two weeks later. Children with Hodgkin's disease had low NK activity. These results suggested that NK cells might play an initial defensive role in VZV infections, and that low NK activity in immunocompromised hosts might contribute to their high incidence of herpes zoster.

Factors influencing the duration of treatment of acute herpetic pain with sympathetic nerve block: importance of severity of herpes zoster assessed by the maximum antibody titers to varicella-zoster virus in otherwise healthy patients

Antibody responses to varicella-zoster virus (VZV) were serially investigated by the complement-fixation test in 72 Japanese of both sexes, suffering from herpes zoster (HZ), but otherwise healthy. Our objective was to elucidate whether there were mutual relationships among severities of skin lesion, maximum antibody titers to VZV, and duration of treatment for acute herpetic pain (AHP). Patients were divided into 3 groups: mild group (n = 26), moderate group (n = 26) and severe group (n = 20), according to the severity of the skin lesions. The 3 groups did not differ significantly with respect to age (P greater than 0.6). All patients were treated with regional sympathetic nerve blocks (SNBs) until pain relief was achieved. The durations of treatment for AHP became significantly longer as HZ increased in severity; the mean log10 durations of treatment (+/- S.E.) for the mild, moderate, and severe groups were 1.383 +/- 0.037, 1.616 +/- 0.055, and 1.888 +/- 0.069 days, respectively (P less than 0.01 for the mild group vs. the moderate group, and P less than 0.001 for the moderate group vs. the severe group). Irrespective of age, the maximum antibody titers closely paralleled the severities of the skin lesion of HZ; the mean maximum log2 antibody titers (+/- S.E.) for the mild, moderate, and severe groups were 5.12 +/- 0.24, 6.73 +/- 0.20, and 8.00 +/- 0.18, respectively (P less than 0.001 for the mild group vs. the moderate group and for the moderate group vs. the severe group).(ABSTRACT TRUNCATED AT 250 WORDS)

Impact and costs of varicella prevention in a university hospital

Information regarding all patient and staff exposures to varicella-zoster virus (VZV) was prospectively accumulated from 1/1/86 to 12/31/86 at North Carolina Memorial Hospital. During this period of time 37 sources of exposure to VZV were reported: 10 outside and 27 within the hospital. Index cases for nosocomial exposure included: 12 patients with zoster, 9 patients with varicella, two staff with varicella, three visitors with varicella, and one staff with zoster. One hundred and twenty patients received nosocomial exposures; 28 had no history of VZV infection (23 per cent), of whom 11 were serosusceptible (39 per cent). Sources of nosocomial patient exposure included: other patients (85 per cent), staff (14 per cent), and a single visitor (1 per cent). More than 300 employees received nosocomial exposure; 158 had no history of VZV infection, of whom 49 were serosusceptible (31 per cent). Only a single employee and no patients developed clinical varicella as a result of nosocomial exposure. Costs associated with VZV control during 1986 totaled $55,934: $39,658 for work furloughs, $9,800 for serologies, $4,293 for patient isolation, $155 for varicella-zoster immune globulin, and $2,028 for infection control personnel time. These costs should be considered as part of any benefit-cost analysis of varicella immunization of health care personnel.

Varicella zoster virus is a cause of the acute retinal necrosis syndrome

We studied two blind eyes enucleated during the active phase of the acute retinal necrosis syndrome. Both eyes showed similar histopathologic findings of necrotizing retinitis, retinal arteritis, and optic neuropathy. A virus morphologically consistent with a herpes group virus was found on electron microscopy and immunocytopathologic stains showed this virus to be varicella zoster in both cases. Varicella zoster virus was cultured from the vitreous of one of the eyes. We conclude that varicella zoster virus retinal infection is a cause of the acute retinal necrosis syndrome.

An algorithm for the control of nosocomial varicella-zoster virus infection

Inadvertent or uncontrolled introduction of varicella-zoster virus into the hospital environment occurs commonly and must be investigated in a systematic and efficient manner to minimize secondary spread to patients (particularly the immunocompromised) or hospital personnel. On the basis of a review of the literature and our practical experience with 11 such exposures to varicella-zoster virus during a 2-year period, we have developed a working algorithm for such investigations. Index cases most often are children, resident physicians, students, young nurses, and ancillary personnel, or adult patients with herpes zoster. A negative or uncertain past history of this infection is an unreliable predictor of susceptibility among the exposed and should be confirmed by serology tests or delayed hypersensitivity skin testing. An incubation-contagion timetable, coupled with a stratification of risk among the exposed, permits a prioritized response in dealing with an introduction of varicella-zoster virus. The preemployment screening of all hospital workers for susceptibility to varicella-zoster virus should be considered as a practical and cost effective policy.

Human leukocytes kill varicella-zoster virus-infected fibroblasts in the presence of murine monoclonal antibodies to virus-specific glycoproteins

Seven murine monoclonal antibodies reacting with major glycoproteins of varicella-zoster virus were tested for functional activity in assays for antibody-dependent cellular cytotoxicity (ADCC) and antibody-plus-complement-mediated lysis. Human peripheral blood mononuclear cells killed varicella-zoster virus-infected fibroblasts in the presence of three of four monoclonal antibodies directed against gp98/62 and a single monoclonal antibody directed against gp118. Neither of two monoclonal antibodies directed against gp66 was able to mediate ADCC. In 18-h assays, adherent effector cells were more active than nonadherent effector cells in mediating ADCC. Adherent cells treated with anti-Leu-11b and complement retained their cytotoxic activity, suggesting that monocytes are responsible for most of the adherent-cell-mediated cytotoxicity. Both immunoglobulin G1 and G2a murine monoclonal antibodies were able to participate in ADCC. Of the two immunoglobulin G2a monoclonal antibodies tested, both of which reacted with gp98/62, only one mediated lysis in the presence of complement. These results indicate that some murine monoclonal antibodies against major glycoproteins of varicella-zoster virus have functional activity in cytotoxicity assays.

Incomplete growth of varicella-zoster virus in human monocytes

Infection of human peripheral blood monocytes by varicella-zoster virus (VZV) was investigated. When freshly isolated monocytes of young adult volunteers were infected with cell-free VZV and examined by indirect immunofluorescence, specific antigens appeared at 8 hr and the number of antigen-positive cells reached the maximum between 24 and 48 hr postinfection. The proportion of antigen-positive cells to total cells was similar to that of the permissive control (HeLa cells), while very few infectious centers (IC) of monocytes were formed in comparison with the infected control cells. Monocytes isolated from infants and old persons formed a larger number of IC than those of young adults. Electron microscopic study of VZV-infected monocytes from three young adult volunteers demonstrated that the proportion of VZV particle-positive cells to total cells was similar to that of antigen-positive cells, and most of the particles seen in the nuclei were low in density and lacked a central core. These results suggest that the growth of VZV in human adult monocytes is incomplete. This restriction of VZV growth by monocytes may play an important role in defense against VZV infection.