Specific immunoglobulin responses after varicella and herpes zoster

Evidence of varicella zoster virus (VZV) reactivation in children with arterial ischemic stroke: Results of the VIPS II Study

Background

Varicella zoster virus (VZV) has been associated with focal cerebral arteriopathy (FCA) and arterial ischemic stroke (AIS) in childhood. The Vascular effects of Infection in Pediatric Stroke (VIPS) II study aimed to examine this relationship in the modern era when most children in North America and Australia receive VZV vaccination with live, attenuated virus.

Methods

This 22-center prospective cohort study enrolled 205 children (28 days-18 years) with AIS (2017-2022), collected baseline [hyperacute (≤72 hours; n=194) and acute (4-6 days; n=181)] and convalescent (1-6 weeks; n=74) serum samples. Sites enrolled 95 stroke-free controls with single serum samples. A virology research laboratory measured VZV IgM and IgG titers by an in-house enzyme-linked immunosorbent assay (ELISA). Baseline IgG seropositivity indicated prior exposure (vaccination/infection) and elevated IgM titers indicated recent reactivation.

Results

Median (IQR) age was 11.6 (5.5-15.6) years for cases and 11.8 (6.8-15.3) years for controls. Baseline serologies indicated prior VZV exposure in 198 cases (97%) and all controls. Parents of cases reported VZV vaccination in 160 (78%) and remote chicken pox in three (1.4%). Twenty cases (9.8%) and three controls (3.1%) had serologic evidence of recent VZV reactivation (p=0.06); all had remote VZV exposure (vaccination in 19 cases and all controls) and all were asymptomatic. Recent VZV reactivation was seen in similar proportions in arteriopathic, cardioembolic, and idiopathic stroke. Of 32 cases of FCA, 4 (12.5%) had recent VZV reactivation, versus no cases of arterial dissection (n=10) or moyamoya (n=16).

Conclusions

Serologic evidence of recent VZV reactivation (≈1-6 weeks prior to stroke) was present in one in 10 cases of childhood AIS, including those without arteriopathy. Clinically silent VZV reactivation may be a childhood stroke trigger despite widespread vaccination. These cases could represent waning immunity with reactivation of either vaccine virus or wild-type virus after an unrecognized secondary VZV infection.

Diagnostic Usefulness of Varicella Zoster Virus-Specific Immunoglobulin (Ig) A and IgG in Patients With Herpes Zoster

BACKGROUND

Whether varicella zoster virus (VZV) antibody titer could discriminate patients with herpes zoster (HZ) from healthy controls (HCs) is unclear. We evaluated the diagnostic usefulness of VZV-specific immunoglobulin A (IgA) and immunoglobulin G (IgG) antibodies in patients with confirmed HZ.

METHODS

Study subjects comprised patients with confirmed HZ by salivary VZV DNA positivity and control age- and sex-matched HCs. Saliva was collected and concurrent blood samples were obtained on the first visit day (acute phase) and after 4 weeks (convalescent phase) from 44 HZ patients. All 44 healthy volunteers provided blood and saliva samples once.

RESULTS

The median VZV IgA titers in acute-phase (5.2 mIU/mL, P < 0.001) and convalescent-phase (15.8 mIU/mL, P < 0.001) serum samples from HZ patients were significantly higher than those in HCs (1.35 mIU/mL). VZV IgA positivity was detected in about 20% of acute phase serum and convalescent-phase serum of HZ patients. The median VZV IgG antibody titers of HZ patients during acute (1,471.0 mIU/mL, P < 0.001) and convalescent (4,934.7 mIU/mL, P < 0.001) phases were significantly higher than the median titer reported for HCs (591.6 mIU/mL). A four-fold or higher increase in VZV IgG antibody titer was observed in 36.4% of HZ patients.

CONCLUSION

VZV IgA positivity or four-fold or higher increase in VZV IgG antibody titers were not detected in a satisfactory proportion of HZ-infected patients. However, the titer of VZV IgA or IgG antibody particularly in convalescent-phase sera may discriminate HZ patients from HCs.

Systemic lupus erythematosus with visceral varicella: A case report

BACKGROUND

As an autoimmune disease, systemic lupus erythaematosus (SLE) can affect multiple systems of the body and is mainly treated by steroids and immunosuppressive agents. SLE results in a long-term immunocompromised state with the potential of infection complications (e.g., bacterial, fungal and viral infections). Abdominal pain or acute abdomen are frequently the only manifestations of SLE at disease onset or during the early stage of the disease course. Thus, multidisciplinary collaboration is required to identify these patients because timely diagnosis and treatment are crucial for improving their prognosis.

CASE SUMMARY

Herein, we reported a case of an SLE patient with visceral varicella that was identified after the onset of abdominal pain. The 16-year-old female patient with SLE was admitted to our hospital due to initial attacks of abdominal pain and intermittent fever. The patient’s condition rapidly became aggravated within a short time after admission, with large areas of vesicular rash, severe pneumonia, respiratory failure, shock, and haematologic system and hepatic function impairment. Based on multidisciplinary collaboration, the patient was diagnosed with visceral disseminated varicella and was administered life support, antiviral (acyclovir), immunomodulatory (intravenous injection of human immunoglobulin), anti-infection (vancomycin) and anti-inflammatory (steroid) therapies. After treatment, her clinical symptoms and laboratory indicators gradually improved, and the patient was discharged.

CONCLUSION

SLE patients long treated with steroids and immunosuppressive agents are susceptible to various infections. Considering that visceral varicella with abdominal pain as the initial presentation is characterized by rapid progression and often coexists with serious complications, prompt diagnosis and early antiviral therapy are critical to prevent severe life-threatening complications.

Healed Varicella Pneumonia: A Case of Diffuse Pulmonary Microcalcifications

Varicella pneumonia is a potentially fatal complication of the Varicella-zoster virus (VZV), which causes the well-known chickenpox disease of childhood. Identifying this type of pneumonia by characteristic features is important for radiologists and radiology residents. Typical manifestations of active Varicella pneumonia include diffuse pulmonary nodules, which may mimic other diseases. Healed Varicella pneumonia can present as diffuse, calcified pulmonary micronodules. We describe a case of healed Varicella pneumonia in a patient with a history of remote VZV infection.

Reactivation of varicella-zoster virus in reversible cerebral vasoconstriction syndrome: a proof-of-concept study

Aim: Association between reversible cerebral vasoconstriction syndrome (RCVS) and the reactivation of varicella-zoster virus (VZV) was analyzed. Materials & methods: VZV-specific IgG and IgA responses on day 1 and 28 in plasma was compared and VZV DNA with real-time PCR in saliva was measured in case-patients (diagnosed with RCVS), control-patients (ischemic stroke with intracranial artery stenosis) and healthy volunteers. Results: The case-patients (n = 11) revealed significantly higher VZV-specific IgG levels on day 28 than on day 1 (p = 0.004), while the age-matched control-patients and healthy volunteers exhibited no significant changes. Positive VZV DNA PCR result in saliva was revealed in one case-patient. Conclusion: RCVS might be associated with VZV. This result warrants a full-scale study to evaluate the association between them.

Longitudinal analysis of varicella-zoster virus-specific antibodies in systemic lupus erythematosus: No association with subclinical viral reactivations or lupus disease activity

Systemic lupus erythematosus (SLE) patients are at high risk of herpes zoster. Previously, we found increased immunoglobulin (Ig)G levels against varicella-zoster virus (VZV) in SLE patients compared to controls, while antibody levels against diphtheria and cellular immunity to VZV were decreased. We aimed to test our hypothesis that increased VZV-IgG levels in SLE result from subclinical VZV reactivations, caused by stress because of lupus disease activity or immunosuppressive drug use.

Decreased Immunity to Varicella Zoster Virus in Giant Cell Arteritis

Introduction

Herpes zoster, which can have a major impact on quality of life, results from reactivation of a latent varicella zoster virus (VZV) infection. We hypothesized that giant cell arteritis (GCA) patients are at increased risk of herpes zoster because of treatment with high-dose glucocorticoids and advanced age. Aim of the study, therefore, was to determine cell-mediated and humoral immunity to VZV in patients with GCA, patients with closely related disease polymyalgia rheumatica (PMR; treated with lower doses of glucocorticoids) and healthy controls (HCs).

Methods

Cell-mediated immunity to VZV was determined by performing interferon-γ (IFNγ) enzyme-linked immunospot and intracellular cytokine flow cytometry measurements in 11 GCA and 15 PMR patients and in 26 age/sex-matched HCs. Immunoglobulin G antibodies to VZV glycoprotein (VZV-IgG) were measured in serum samples of 35 GCA and 26 PMR patients at different times of follow-up and in 58 age and sex-matched HCs by an enzyme-linked immunosorbent assay.

Results

The number of VZV-specific IFNγ spot-forming cells was significantly lower in GCA patients on treatment, than in age-matched HCs (p = 0.029), but was not different in PMR patients on treatment. Similar levels of VZV-IgG were found in GCA and PMR patients at baseline, compared to HCs.

Conclusion

The finding of a decreased cell-mediated immunity to VZV, known to be of great importance in defense to the virus, indicates an increased herpes zoster risk in GCA patients compared to an already at-risk elderly population. Herpes zoster vaccination is, therefore, of special importance in GCA patients, and would ideally be administered at time of diagnosis. Interestingly, as VZV was suggested to be the trigger in GCA pathogenesis, similar levels of VZV-IgG were found in GCA patients at time of diagnosis and age-matched HCs, indicating that GCA patients did not experience herpes zoster substantially more often in the months preceding diagnosis than controls.

Microbiology laboratory and the management of mother-child varicella-zoster virus infection

Varicella-zoster virus, which is responsible for varicella (chickenpox) and herpes zoster (shingles), is ubiquitous and causes an acute infection among children, especially those aged less than six years. As 90% of adults have had varicella in childhood, it is unusual to encounter an infected pregnant woman but, if the disease does appear, it can lead to complications for both the mother and fetus or newborn. The major maternal complications include pneumonia, which can lead to death if not treated. If the virus passes to the fetus, congenital varicella syndrome, neonatal varicella (particularly serious if maternal rash appears in the days immediately before or after childbirth) or herpes zoster in the early years of life may occur depending on the time of infection. A Microbiology laboratory can help in the diagnosis and management of mother-child infection at four main times: (1) when a pregnant woman has been exposed to varicella or herpes zoster, a prompt search for specific antibodies can determine whether she is susceptible to, or protected against infection; (2) when a pregnant woman develops clinical symptoms consistent with varicella, the diagnosis is usually clinical, but a laboratory can be crucial if the symptoms are doubtful or otherwise unclear (atypical patterns in immunocompromised subjects, patients with post-vaccination varicella, or subjects who have received immunoglobulins), or if there is a need for a differential diagnosis between varicella and other types of dermatoses with vesicle formation; (3) when a prenatal diagnosis of uterine infection is required in order to detect cases of congenital varicella syndrome after the onset of varicella in the mother; and (4) when the baby is born and it is necessary to confirm a diagnosis of varicella (and its complications), make a differential diagnosis between varicella and other diseases with similar symptoms, or confirm a causal relationship between maternal varicella and malformations in a newborn.

Innate recognition of alphaherpesvirus DNA

Alphaherpesviruses include human and animal pathogens, such as herpes simplex virus type 1, which establish life-long latent infections with episodes of recurrence. The immunocompetence of the infected host is an important determinant for the outcome of infections with alphaherpesviruses. Recognition of pathogen-associated molecular patterns by pattern recognition receptors is an essential, early step in the innate immune response to pathogens. In recent years, it has been discovered that herpesvirus DNA is a strong inducer of the innate immune system. The viral genome can be recognized in endosomes by TLR9, as well as intracellularly by a variety of DNA sensors, the best documented being cGAS, RNA Pol III, IFI16, and AIM2. These DNA sensors use converging signaling pathways to activate transcription factors, such as IRF3 and NF-κB, which induce the expression of type I interferons and other inflammatory cytokines and activate the inflammasome. This review summarizes the recent literature on the innate sensing of alphaherpesvirus DNA, the mechanisms of activation of the different sensors, their mechanisms of signal transduction, their physiological role in defense against herpesvirus infection, and how alphaherpesviruses seek to evade these responses to allow establishment and maintenance of infection.

Human herpes viruses in pregnancy: cytomegalovirus, Epstein-Barr virus, and varicella zoster virus

Viruses of the human herpesvirus family can have profound effects on pregnancy. Primary maternal infection with cytomegalovirus (CMV) and varicella during pregnancy has been associated with fetal abnormalities and neonatal disease. Public awareness of the role of cytomegalovirus in the etiology of developmental disorders and chronic disabilities needs to increase. With time, we may see new interventions for treatment of infected pregnant women and prevention of long-term effects. Attention must be focused on development of a safe and effective vaccine. With the introduction of an efficacious varicella vaccine, the rate of varicella in pregnancy is expected to decrease dramatically. Physicians caring for women have the opportunity to prevent the complications of varicella by identifying and vaccinating susceptible women.

Prevention of postherpetic neuralgia with varicella-zoster hyperimmune globulin

Recovery after an acute attack of herpes zoster is followed by postherpetic neuralgia (PHN) in 9-14% of all patients. Depending on the patient's age, the severity of the acute attack of herpes zoster and the dermatome involved, the incidence of PHN may be as high as 65%. The purpose of our study was to ascertain the incidence of PHN after a prophylactic intravenous injection of varicella-zoster hyperimmune globulin (VZV-IG) (Varitect Biotest Pharma). For this double-blind placebo-controlled randomised investigation we defined PHN as pain confined to the dermatome previously affected by herpes zoster, and we required a pain intensity of at least 15% points on a visual analogue scale (VAS) for this dermatome. The inclusion criteria were the dermatological diagnosis of herpes zoster together with age over 50 years. On Day 1, 20 patients received a single intravenous infusion of VZV-IG in a dose of 2mL/kg body weight, 20 patients (control group) received a single infusion of human albumin 5% in a dose of 2mL/kg body weight. All patients received acyclovir intravenously in a dose of 15mg/kg body weight per 24h for 5 days. The patients were followed up for a total of 42 days. The incidence of PHN at Day 42 was selected as the main outcome criterion for assessing the efficacy of prophylaxis. On reaching a significant difference between the groups (t test; alpha<0.05) in favour of the active treatment group, prophylaxis of PHN by VZV-IG was assessed as effective. Pain was assessed on a VAS and a NAS. As auxiliary outcome criteria, we used the McGill Pain-Rating Questionnaire in its German version, the revised multidimensional pain scale (RMSS) and the Freiburg symptom list (FBL). All results were assessed by the t test (alpha<0.05). The frequency of PHN in the placebo group was 70% (14/20), in the active treatment group it was 35% (7/20) at Day 42. The results of the McGill test showed the variability of the perception of pain in the placebo group significantly greater. No significant group differences were found in the FBL. Being tested with the RMSS, the patients of the placebo group assessed their pains as significantly "more obstinate" (p=0.047). The results can be summed up by saying that VZV-IG not only reduces the incidence of PHN, but also that in certain respects the patients' assessments of their pain experience were different. In our study we found a 50% reduction in PHN incidence However, the outcome time point of our trial was so close to the acute phase of the zoster illness that spontaneous remissions of PHN still have to be taken into account. Despite the widely varied approaches to the problem, reliably effective therapy, let alone 100% prevention of PHN, is still not feasible.

Herpes zoster during varicella

A 4-year-old boy had varicella infection. Two days later vesicular lesions clustered within the left 10th thoracic dermatome. Varicella-zoster virus IgM antibody in serum was positive. He was diagnosed with varicella infection combined with herpes zoster. This is the first case report in the medical literature.

Serological diagnosis of varicella-zoster virus in sera with antibody-capture enzyme-linked immunosorbent assay of IgM

Evaluation was made of three enzyme-linked immunosorbent assay (ELISA) formats; varicella-zoster virus (VZV) indirect ELISA; VZV IgM capture using biotin and VZV IgM capture using peroxidase, for the detection of VZV-specific IgM antibodies in human sera. It was observed that there was no significant difference in sensitivity of detection using the three formats but there were important practical differences in the number of steps and hence time for assay completion between the three assay formats. All assays showed some cross-reactivity with sera containing anti-HSV1 antibodies.

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.

Varicella in pregnancy

Varicella-zoster virus may cause serious infection, particularly pneumonia, in adult women. Women of child-bearing age should be questioned about immunity to varicella preconceptually, and offered serological testing, and VARIVAX vaccine if indicated. All pregnant patients should be questioned about immunity to varicella during their first prenatal appointment. Susceptible patients should be counseled to avoid contact with individuals who have chickenpox. If exposure occurs, VZIG should be administered within 96 hours in an attempt to prevent maternal infection. Varicella embryopathy may occur as a result of maternal infection particularly in the first half of pregnancy with an incidence of 1% to 2%. Varicella of the newborn is a life-threatening illness that may occur when a newborn is delivered within 5 days of the onset of maternal illness or after postdelivery exposure to varicella. Susceptible neonates should receive VZIG. Acyclovir is active against the varicella-zoster virus, and treatment is indicated in seriously ill adults and neonates.

Antiviral prophylaxis and treatment in chickenpox. A review prepared for the UK Advisory Group on Chickenpox on behalf of the British Society for the Study of Infection

Prophylactic intervention with varicella-zoster immunoglobulin early in the incubation period can prevent or attenuate the disease manifestations of varicella in susceptible contacts at high risk from this infection. Detailed guidelines are issued in the UK Department of Health publication on Immunization against Infectious Disease. Sensitive immunoassays are available for investigation of antibody status and subclinical seroconversion. Live attenuated varicella vaccine, which has been used successfully post-exposure as well as electively elsewhere, is at present not generally available in the UK. Effective protocols for prophylaxis against varicella with the antiviral agent aciclovir are not yet established. The nucleoside analogue aciclovir (syn: acyclovir, Zovirax) is effective in inhibiting replication of VZV when given at a dosage higher than that required for treatment of HSV, and is currently the only available and approved treatment for varicella in the U.K. Intravenous aciclovir therapy for 5-10 days is effective for varicella in neonates and the immunocompromised, and for varicella pneumonia or other complications in adults and children, if begun early. Oral aciclovir is only effective if begun with 24 h of onset of rash. With that proviso. it is recommended for treatment of varicella in otherwise healthy adults and adolescents, but not for routine use in children under 13 years of age unless they are sibling contacts or have other medical conditions. Aciclovir has a high therapeutic index and good safety profile, but caution is advised with use in pregnancy.

Herpes zoster ophthalmicus

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Perinatal herpesvirus infections. Herpes simplex, varicella, and cytomegalovirus

The herpesvirus infections (herpes simplex, varicella, and cytomegalovirus) create many dilemmas when encountered during pregnancy. This article reviews the epidemiologic diagnosis and management of perinatal herpesvirus infections. A review of possible future trends is also included.

The detection of varicella zoster antibodies by simultaneous competitive EIA and its comparison with radioimmunoassay, latex agglutination and antiglobulin type EIA

A rapid and simultaneous competitive enzyme immunoassay (EIA) for the detection of human antibodies to varicella zoster virus (VZV) which utilises complement fixing (CF) VZV antigen and peroxidase labelled human antibodies to VZV as reagents is described. The competitive EIA was compared with competitive radioimmunoassay (RIA) in a selection of sera from 501 blood donors and 115 patients. The competitive EIA was comparable in sensitivity and specificity to the RIA, but had the advantage of not requiring radiolabelling or facilities for radioactive handling and disposal, and also had an enhanced stability. The competitive EIA was compared with competitive RIA, a commercially available latex agglutination assay and an antiglobulin type EIA on sera from 100 patients. The competitive EIA and RIA appeared to be the most sensitive tests.

Ophthalmic herpes zoster

A current review of ophthalmic zoster is presented including its virology, immunology, epidemiology and pathogenesis. We give our findings in 1356 patients referred to the Zoster Clinic at Moorfields Eye Hospital, London. The treatment of the disease and its ocular complications is discussed.

Natural killer cell activity in herpes zoster in children without underlying disease

We determined natural killer cell (NKC) activity in 10 otherwise normal children with herpes zoster. NKC activity values in children with vs. without varicella-zoster virus specific IgM antibodies and in controls were 28.3 +/- 8.6%, 11.9 +/- 3.6% and 20.2 +/- 3.8% (mean +/- SD), respectively. There were significant differences between the children with and without IgM antibodies during the acute phase (p < 0.005) and between children without IgM antibodies and controls (p = 0.005). NKC values in children with mild vs. moderate morbidity were 11.7 +/- 4.1% and 25.7 +/- 9.9%, respectively (p < 0.05). The morbidity was moderate in all children with IgM antibodies, but in only 2 of the 5 children without IgM antibodies. Children who contracted varicella when a few months old had the highest IgM antibody titers and the highest value of NKC activity. NKC activity was related both to the presence of IgM antibodies and to the morbidity of herpes zoster.

Antibody-capture enzyme-linked immunosorbent assays that use enzyme-labelled antigen for detection of virus-specific immunoglobulin M, A and G in patients with varicella or herpes zoster

Antibody-capture enzyme-linked immunosorbent assays (AC-ELISA) which use enzyme-labelled antigen were developed for detection of varicella-zoster virus-(VZV) specific IgM, IgA and IgG antibody in patients with varicella or herpes zoster and in sera from healthy individuals. All 18 patients with varicella developed a VZV-IgM and a VZV-IgG response, 17 also a VZV-IgA response. In contrast, all 19 patients with herpes zoster were shown to be positive for VZV-IgA whereas only 13 of these reacted positively for VZV-IgM. A VZV-IgM response was detected in only two sera from 100 healthy individuals and an IgA response in only one. The presence of virus-specific IgA and IgG in the cerebrospinal fluid as determined by AC-ELISA was a useful indicator of VZV infection of the central nervous system. By AC-ELISA, VZV-IgG was detected predominantly in sera from patients with acute or recent VZV infection. Only 14 sera from 100 healthy individuals were positive for VZV-IgG by AC-ELISA, whereas all were positive by an indirect ELISA. These results indicate that AC-ELISA's may be useful assays for determination for acute or recurrent VZV infection, but are not suitable for determination of past infection with this virus.

Diagnosis of acute and latent varicella-zoster virus infections using the polymerase chain reaction

A simplified assay for the diagnosis of varicella-zoster virus (VZV) infections based on the polymerase chain reaction (PCR) is described. Omitting the procedures for extraction and purification of DNA, the crude vesicle fluid materials were used for PCR. Moreover, hybridization was not necessary for detection of the amplification products because they were already visible after ethidium bromide staining of the electrophoresis gel. Results could therefore be obtained within one day. In comparison to virus isolation, PCR proved much more rapid, highly sensitive, and specific. DNA extraction and a double PCR assay with nested primers were necessary for detection of latent VZV infections in trigeminal and thoracic ganglia. The data suggest that the procedures described are universally applicable to several types of specimens dependent on the calculated amount of target DNA.

Definition of high-proficiency serological markers for diagnosis of varicella-zoster virus infections by enzyme immunoassay

The levels of Varicella-zoster virus (VZV)-specific IgG, IgM, and IgA antibodies produced in 22 cases of varicella, 22 cases of cutaneous zoster, and 12 cases of acute aseptic meningitis due to VZV in the absence of cutaneous lesions, were measured by indirect enzyme immunoassay (EIA) and compared with those observed in a group of 34 age-matched controls. The definition of cutoff titres for each serological marker and combinations of them allowed early diagnosis of infection in 82% of varicella patients and 91% of patients with acute aseptic meningitis lacking cutaneous lesions on a single serum sample, the specificity being over 90%. The system was as sensitive as the demonstration of intrathecally produced IgG antibodies for the early diagnosis of the infection in 22 cases of neurological disease due to VZV. A working protocol for the serological diagnosis of VZV infections, using currently available EIA reagents, is described.

Detection of specific IgM in varicella and herpes zoster by antibody-capture radioimmunoassay

A simple and sensitive M antibody-capture radioimmunoassay (MACRIA) is described which utilizes crude commercial VZV antigen and a single monoclonal anti-VZV antibody. This was compared to the immunofluorescence (IF) test for IgM antibody and was used to study IgM responses in sera from 261 patients with varicella and 220 patients with herpes zoster. With MACRIA, IgM antibodies were detected in all patients with varicella. The IgM antibodies appeared shortly after onset of rash, reached peak levels between 1 and 4 weeks after onset and then declined to low or undetectable levels in most, though not all, patients after 3 months. IgM antibodies were also detected in 98.2% of patients with herpes zoster, but the levels of IgM were significantly lower than after varicella and there was wider individual variation both in magnitude and duration of the IgM responses, in some cases only lasting 2-3 weeks. Comparison between MACRIA and IF showed good agreement in the detection of IgM antibodies following varicella. Discordant results were obtained with 13% of sera, of which 81% were taken either early or late after onset of rash and contained very low IgM levels. In contrast, 62 (28%) of the 220 sera from patients with zoster gave discordant results in the two tests, all except five being MACRIA-positive but IF-negative. The largest proportion of discordant results were obtained with sera taken more than 3 months after onset of rash, but 18 (29%) contained high IgM levels and were taken during the period of peak IgM responses. The diagnostic applications of the VZV MACRIA are discussed.

Serological responses in varicella and zoster assayed by immunoblotting

Acute and convalescent zoster sera taken from 11 patients with varicella and 12 patients with zoster were assayed using immunoblotting for the presence of IgG- and IgM-class antibodies to proteins present in varicella-zoster virus-infected cells. All patients exhibited a detectable virus-specific response with both antibody classes. The IgG responses involved up to 28 protein bands between 28 and 255 kilodaltons (kDa). The reactivity was particularly strong in the 78-114-kDa region, with additional bands observed with all patients at 32, 35, 66, and 220 kDa. This pattern of reactivity typically developed more slowly and was weaker and more variable in patients with varicella compared to those with zoster. The reactivity of IgM antibodies in immunoblotting was similar after varicella and after zoster. Individual sera showed up to 25 bands, with the major reactivity being directed against the 78-96-kDa region and two bands at 32 and 35 kDa. Some differences were apparent between the primary and anamnestic responses with both IgG and IgM antibodies, but this did not allow reliable discrimination of the two types of infection.

Natural and artificial immunity to varicella zoster virus

The live varicella vaccine has been recommended for use in immunocompromised subjects and in adults who are susceptible to chickenpox. However, we do not know how humoral and cell-mediated immune responses induced after vaccination differed from those obtained after natural infection. To answer this, 45 previously infected subjects (23 chickenpox, 22 vaccinated) were tested for their varicella zoster virus (VZV)-specific antibody levels and for their lymphocyte stimulation responses to VZV antigen. Antibody was measured by both an enzyme-linked immunosorbent assay (ELISA) and an immunofluorescence assay (IF), while lymphocyte stimulation was detected by tritiated thymidine incorporation. Antibody was tested in ten postchickenpox and nine vaccinated subjects. About 6 to 8 weeks after first exposure, the magnitude of the responses determined by both ELISA and IFT were much higher in the naturally infected than in the vaccinated group (P less than 0.001) with both test methods). There was no significant difference in the lymphocyte transformation responses in both groups of subjects. Thirteen postchickenpox and 13 vaccinated subjects who had been infected at least 12 months previously were also tested. Total antibody levels were again significantly higher in the naturally infected than in the vaccinated group (P less than 0.001). One vaccinated subject had VZV-specific IgA and IgM in the serum. The magnitude of the lymphocyte transformation reaction was higher in the naturally infected than in the vaccinated group (P less than 0.01). Thus, antibody responses to VZV were better in naturally infected than in vaccinated subjects. The IFT appears to be a more sensitive technique for antibody detection in the vaccinated subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

The potency determination of human varicella-zoster immunoglobulin by enzyme-linked immunosorbent assay, complement-fixation test and indirect fluorescent antibody tests

Traditionally, plasma for the production of the human varicella-zoster immunoglobulin (VZIG) has been selected on the basis of the complement-fixing antibody (CFA) titre. Since immune individuals may lack CFA to varicella-zoster virus (VZV), non-CFA may be of importance in protection. In a search for a simple and reliable method for potency determination, 24 VZIG preparations were quantified by enzyme-linked immunosorbent assay (ELISA), the complement-fixation test (CFT), the indirect fluorescent antibody test to acetone-fixed (IF) and viable (FAMA) VZV-infected cells, respectively. The antibody titres obtained by the various methods were compared. Arranged in order of decreasing agreement, the correlation coefficients (r) of the regression equations between the variables were 0.62 for CFT and FAMA, 0.50 for CFT and ELISA and 0.26 for CFT and IF in a log2 plot. There was complete agreement between the titres obtained by the commercially available Enzygnost Varicella/Zoster kits (Behring Institute, Marburg, F.R. Germany) and the ELISA microtitre plates produced at our institute (r = 1). The regression equation lines for ELISA/CFT and FAMA/CFT titres tended to be parallel to each other, while the line for IF/CFT titres had a less steep slope. Similar titration curves were obtained for VZIGs fractionated by two different methods. Furthermore, the titration curves of serum pools from varicella and zoster convalescents, respectively, had a similar shape below delta OD = 0.4. Generally, a steeper slope was observed above delta OD = 0.4. As antibody detectable by ELISA seems to correlate with protection and the method is sensitive, specific, reproduceable, simple to carry out and easily automated, it may be suitable for the potency determination of VZIGs.

Development of an immunofluorescence test for the serodiagnosis of herpes zoster ophthalmicus

An indirect immunofluorescence test has been developed and evaluated for the serodiagnosis of herpes zoster ophthalmicus (HZO) by the detection of antivaricella zoster virus (VZV) antibody. The results show that, in patients with HZO, anti-VZV IgG antibody titre usually rises rapidly after onset. One hundred and seven of the 134 sera (80%) from patients with a clinical diagnosis of HZO had an anti-VZV IgG titre of greater than or equal to 256, and IgM antibody at a level of 1 in 8 was present in six of them. In comparison only two of the 216 sera (1%) from patients with a clinical diagnosis of ocular infections other than those caused by VZV had such IgG titres. It was concluded that, on the basis of results of a single sample of serum, it is possible to make a provisional diagnosis of HZO with a high degree of confidence.

Sensitivity of different assay systems for immunoglobulin M responses to varicella-zoster virus in reactivated infections (zoster)

An immunoglobulin M response to varicella-zoster virus was detected in 70% of zoster patients by solid-phase radioimmunoassay, in 52% by indirect immunofluorescence, in 48% by neutralization on sucrose density gradient fractions, and in 27% by an antibody class capture enzyme immunoassay. The patients showed marked variations in their varicella-zoster virus immunoglobulin M responses detectable in the different assays.

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 outbreak of shingles?

7 of 101 staff within one department of a large office complex had shingles, as diagnosed by a general practitioner, within a three-month period. This incidence was significantly greater than that in the remaining workforce. Varicella-zoster-specific IgM antibody was detected in all 4 cases from whom early convalescent serum samples were obtained but in none of 22 controls. Within the index department there was evidence of clustering in time and by work area. A case/control study showed that a recent preceeding illness might have been a risk factor for shingles in the outbreak cases, but not for sporadic cases in other departments of the same office complex. This outbreak suggests that shingles can be provoked by reexposure to varicella-zoster virus.

Determination of human IgG and IgM class antibodies to West Nile virus by enzyme linked immunosorbent assay (ELISA)

An enzyme-linked immunosorbent assay (ELISA) was developed and used for the detection of IgG and IgM antibodies to West Nile virus in human sera. Thirteen paired sera of clinical cases and 24 control sera taken randomly from a blood bank repository were tested. The sera were reacted in microtiter plates coated with PEG-treated WNV antigen. IgG or IgM antibodies were quantitated by the use of alkaline-phosphatase-conjugated anti-human IgG or IgM antibodies. Of the 24 randomly collected serum samples, 7 were positive in the IgG-ELISA test. One positive by the IgM-ELISA was found to contain rheumatoid factor. In 12 of 13 paired sera of clinical cases, IgM as well as IgG antibodies were detected in the second serum sample taken about 3 wk after the onset of clinical signs. The IgM positive sera were screened for rheumatoid factor (RF) on IgG-coated plates. None of them contained RF. Antibody titers obtained by ELISA showed a good correlation with titers obtained by hemagglutination inhibition, complement fixation, and neutralization tests. The ELISA tests for detection of IgM and IgG antibodies to WNV therefore can replace the other serological methods for epidemiological surveillance and diagnostic purposes.

Immunisation of nurses with a live varicella vaccine

34 nurses who had no previous history of chickenpox and were seronegative to varicella zoster virus (VZV) were immunised with a live attenuated varicella vaccine (OKA-RIT strain) and followed up for up to 36 months. No major vaccine reactions were observed. At 5 months and at 1 year, 94% of the nurses had seroconverted but at 3 years only 64% had detectable antibody. Lymphocyte transformation to VZV antigen tested in seven nurses in whom antibody was no longer detectable gave positive stimulation indices. 2 of 13 vaccinated nurses who looked after children with chickenpox became infected but 1 of them had not seroconverted after vaccination. Chickenpox developed in 6 out of 7 unvaccinated seronegative nurses who looked after children with chickenpox. This study shows that the OKA-RIT strain VZV vaccine is safe and immunogenic in adults and may therefore be considered for use in susceptible health care workers. The investigations also show that both cell-mediated and antibody tests are needed for long-term assessment of immunity to chickenpox after vaccination.

Use of enzyme-labeled antigen for the detection of immunoglobulin M and A antibody to herpes simplex virus in serum and cerebrospinal fluid

A direct enzyme-linked immunosorbent assay (ELISA that used peroxidase-labeled antigen) was developed for detection of IgM and IgA antibody to herpes simplex virus (HSV). The assay uses immuno-affinity-purified antihuman IgM or IgA antibody-coated wells of microtiter plates to separate IgM or IgA from other classes of antibody in serum or cerebrospinal fluid (CSF). The presence of specific IgM or IgA is detected by subsequent, consecutive incubation with peroxidase-labeled antigen and substrate. HSV antigen was purified by sucrose gradient centrifugation and coupled with peroxidase by the periodate method. By examining sucrose-gradient-fractionated sera the assays were shown to be specific for IgM and IgA classes of antibody. None of the sera from patients with Epstein-Barr virus (n = 20), cytomegalovirus (n = 20), or varicella-zoster virus (n = 8) infection or with both rheumatoid factor and IgG antibody to HSV (n = 13) reacted positively. Only one out of 78 sera from healthy persons was positive for IgA antibody to HSV, and none for IgM antibody. All 33 patients with HSV infection developed HSV-IgA, 22 developed HSV-IgM. Of the 11 patients with primary infection, all had IgM antibody in their first sera and six had IgA antibody. The corresponding figures for the 22 patients with recurrent infection were five and nine. Furthermore, HSV-IgA antibody was found in serum and CSF of all five patients with HSV encephalitis in the second week after onset of symptoms, indicating the usefulness of the assay as a noninvasive technique for diagnosing HSV encephalitis.

Antibody class capture assays for varicella-zoster virus

Pooled monoclonal antibodies to varicella-zoster virus (VZV) were used as "detector" antibodies in a four-phase enzyme immunofluorescence assay for determination of immunoglobulin M (IgM), IgA, and IgG antibodies to VZV. Polyclonal antisera specific for heavy chains of human IgM, IgA, and IgG were employed as "capture" antibodies on the solid phase. The antibody class capture assay (ACCA) for VZV IgM antibody detected high titers of virus-specific IgM in all patients with varicella and in 5 of 10 zoster patients. VZV IgM antibody was not detected in patients with primary herpes simplex virus infections or in other individuals without active VZV infection, with one exception, a patient with encephalitis who had other serological findings compatible with a reactivated VZV infection. VZV-specific IgA and IgG antibody titers demonstrable by ACCA were compared with those measured by solid-phase indirect enzyme immunofluorescence assay (EIFA). VZV IgA antibody titers detected in patients with varicella and zoster were variable and could not be considered to be reliable markers of active VZV infection. IgA antibody titers detected by ACCA tended to be higher than those demonstrated by solid-phase indirect EIFA in varicella and zoster patients. VZV IgG antibody titers detected by ACCA in patients with varicella, and to a lesser extent in zoster patients, were as high as or higher than those demonstrated by solid-phase indirect EIFA. However, ACCA was totally insensitive in detecting VZV IgG antibody in individuals with past infections with VZV and would not be a suitable approach for determination of immunity status to VZV.

Antibody assays for varicella-zoster virus: comparison of competitive enzyme-linked immunosorbent assay (ELISA), competitive radioimmunoassay (RIA), complement fixation, and indirect immunofluorescence assays

The competitive ELISA test was compared with competitive RIA, complement fixation, and indirect fluorescent antibody test for the detection of antibody to varicella-zoster virus (VZV). ELISA and RIA were the most sensitive tests, being tenfold as sensitive as indirect immunofluorescence and 20 times as sensitive as complement fixation, which was surprisingly inadequate for detecting anti-VZV in sera from regular haemodialysis patients. The ELISA test was found to be the most suitable assay, employing a routine complement fixation test (CFT) grade viral antigen and not requiring radiolabelling and counting facilities, which are unavailable in most virology laboratories.

Enzyme-linked immunosorbent assay that uses labeled antigen for detection of immunoglobulin M and A antibodies in toxoplasmosis: comparison with indirect immunofluorescence and double-sandwich enzyme-linked immunosorbent assay

A direct enzyme-linked immunosorbent assay (ELISA) is described that uses horseradish peroxidase-labeled antigen for detection of immunoglobulin M (IgM) and IgA antibodies to toxoplasma. In this assay, polystyrene microtiter plates were sensitized with anti-human IgM or IgA antibody to separate IgM or IgA from other classes of antibody. The presence of IgM or IgA antibodies to toxoplasma (Tox-IgM, Tox-IgA) was then detected by sequential addition of soluble horseradish peroxidase-labeled toxoplasma antigen and substrate. As judged by examining sucrose gradient-fractionated sera, the assay was specific for IgM or IgA classes of antibody. In contrast to the indirect immunofluorescence for IgM antibodies to toxoplasma, no inhibition of IgM reactivity by specific IgG antibodies could be detected. Furthermore, rheumatoid factor did not cause false-positive results. Of 80 single sera with high antibody titer to toxoplasma in indirect immunofluorescence and complement fixation, 40 were positive in the direct ELISA for Tox-IgM, 36 were positive in the double-sandwich ELISA, and only 21 were positive in the indirect immunofluorescence for Tox-IgM when whole serum was used. In the indirect immunofluorescence, another 13 sera became positive after sucrose gradient fractionation. The direct ELISA for IgA antibodies to toxoplasma was positive in 43 sera, of which 39 were positive in the direct ELISA for Tox-IgM. High levels of IgM antibodies were found within 3 months after the onset of symptoms, slowly decreasing thereafter. Tox-IgM may persist for more than 1 year after infection.

A comparison of indirect immunofluorescence and radioimmunoassay for detecting antibody to varicella-zoster virus

Immunofluorescence (IF) and radioimmunoassay (RIA) were found to be more sensitive methods than complement fixation (CF) for detecting antibody to varicella-zoster (V-Z) virus. RIA yielded titres about 30 times greater than those obtained by IF, but for screening purposes RIA was only about six times more sensitive since the minimum serum dilutions that could be tested were 1/100 and 1/16 respectively. When 539 sera from subjects of different ages were screened for V-Z antibody, IF and RIA gave concordant results with 527 specimens (98%). When 19 patients were tested who had not previously had varicella but were experiencing primary infection with herpes simplex (HS) virus, crossreacting antibodies to V-Z antigens were detected in six patients by IF but in only two of these by RIA. IF and RIA are preferable to CF as tests for immune status because of their greater sensitivity, but weak positive reactions caused by presumptive low titres of homologous antibody or by higher titres of heterologous antibody can occur in one or both tests. Such reactions could cause difficulty in assessing the need for vaccine or for specific immune globulin, and in interpreting the response to vaccination.

Specific IgM class antibody production following infection with cytomegalovirus

Specific IgM class antibody production was studied in different groups of patients with characterized cytomegalovirus (CMV) infections using a radioimmunoassay (RIA). In pregnant women, IgM antibodies were detected only following primary infection and generally persisted less than 4 months. The demonstration of CMV-specific IgM during pregnancy is therefore diagnostic of recent primary CMV infection. In patients with symptomatic CMV infections, the appearance of IgM antibody was shown to be closely related to the onset of symptoms and coincided with production of complement fixing (CF) antibody. IgM antibodies were at maximum levels 3-4 weeks after presentation but generally declined to low or undetectable levels by 3-4 months. The significance of the results of testing for CMV-specific IgM in relation to clinical and other serological findings in these patients is discussed. IgM antibody production was also demonstrated in renal transplant patients with primary infections and in 6 of 21 recipients with secondary infections. In both groups the antibodies became detectable 3-6 weeks after transplantation but the titres were much higher following primary infection. IgM antibodies persisted throughout follow-up periods of up to 2 years after transplantation in some cases.

Detection of antibody to varicella-zoster virus by competitive and IgM-antibody capture immunoassay

A simple, sensitive, and specific competitive solid phase immunoassay for antibody to varicella-zoster virus (anti-VZV) is described. The assay uses reagents that can easily be prepared and is sparing of viral antigen. Using a solid phase coated with sheep IgG from a serum raised against human mu-Fc, the same reagents will accurately detect anti-VZV IgM. The competitive assay divided sera from children from adults into immune and nonimmune groups that closely correlated with a history of previous VZV illness. It was not affected by the presence or absence of antibody to other herpes viruses. The IgM antibody capture assay demonstrated the presence of anti-VZV IgM in sera from patients with both varicella and zoster and gave negative results in patients with infections unrelated to VZV and in healthy blood donors.

Immunoglobulins M and G to varicella-zoster virus measured by solid-phase radioimmunoassay: antibody responses to varicella and herpes zoster infections

Both immunoglobulin M (IgM) and IgG antibodies to varicella-zoster virus (VZV) were detectable in a solid-phase radioimmunoassay with 125I-labeled goat antisera to human immunoglobulins. Primary infection with VZV was associated with early production of IgM and IgG antibodies and rapid development of lymphocyte transformation to VZV antigen. Among eight subjects with varicella tested 1 to 4 days after onset, seven patients had IgG and six patients had IgM antibodies; all patients had both IgG and IgM antibodies within 7 days. An IgM response was documented by radioimmunoassay in 18 of 26 patients with herpes zoster. VZV antibodies could be assayed by radioimmunoassay in unfractionated serum with commercial goat antisera to human immunoglobulins and commercial VZV antigen. VZV-specific IgG binding was present in all sera from 42 subjects with a VZB antibody titer of greater than or equal to 1:8 as determined by indirect immunofluorescence and cellular immunity to VZV as determined by lymphocyte transformation and who had had varicella at least 20 years before testing. The geometric mean titer was 1:6,309, and titers were greater than or equal to 1:16,384 in 20 subjects. Antibody was present as determined by radioimmunoassay in 14 samples negative by complement fixation and in five samples negative by complement fixation and immune adherence hemagglutination. No specific binding was observed in 21 sera from subjects who were not immune to VZV as determined by indirect immunofluorescence or lymphocyte transformation despite the presence of herpes simplex or cytomegalovirus antibody indicated by complement fixation in 15 sera. High titers of VZV IgM antibody were detected in unfractionated sera despite the presence of high titers of VZV IgG antibody. The VZV radioimmunoassay provided a sensitive and practical method for measuring VZV IgG and IgM antibodies.

Human anti-chickenpox immunoglobulin in the prevention of chickenpox

Human anti-chickenpox immunoglobulin (zoster immune globulin, ZIG) was largely ineffective in preventing infection in forty-three high-risk contacts of chickenpox. Twenty-nine of these non-immune infants and children who had been in close contact with cases of varicella became infected, and symptoms developed in twenty-four. Since ZIG may modify chickenpox it should continue to be given to high-risk contacts until the availability of a simple and sensitive test makes it possible to identify those who are susceptible. However, ZIG is not necesary for infants whose mothers have chickenpox or zoster five or more days before delivery, since all such infants (eleven) had varicella-zoster antibody at birth.